MAINT: refactor/please mypy.

With this mypy should be happier, and some files should be properly
typed.

.github/workflows/mypy.yml

@@ -1,41 +1,38 b''
 name: Run MyPy
 
 on:
   push:
     branches: [ main, 7.x]
   pull_request:
     branches: [ main, 7.x]
 
 permissions:
   contents: read
 
 jobs:
   build:
 
     runs-on: ubuntu-latest
     strategy:
       matrix:
         python-version: ["3.x"]
 
     steps:
     - uses: actions/checkout@v3
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install mypy pyflakes flake8
+        pip install mypy pyflakes flake8 types-decorator
     - name: Lint with mypy
       run: |
         set -e
-        mypy -p IPython.terminal
-        mypy -p IPython.core.magics
-        mypy -p IPython.core.guarded_eval
-        mypy -p IPython.core.completer
+        mypy IPython
     - name: Lint with pyflakes
       run: |
         set -e
         flake8  IPython/core/magics/script.py
         flake8  IPython/core/magics/packaging.py

IPython/core/formatters.py

@@ -1,1026 +1,1028 b''
 # -*- coding: utf-8 -*-
 """Display formatters.
 
 Inheritance diagram:
 
 .. inheritance-diagram:: IPython.core.formatters
    :parts: 3
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import abc
 import sys
 import traceback
 import warnings
 from io import StringIO
 
 from decorator import decorator
 
 from traitlets.config.configurable import Configurable
 from .getipython import get_ipython
 from ..utils.sentinel import Sentinel
 from ..utils.dir2 import get_real_method
 from ..lib import pretty
 from traitlets import (
     Bool, Dict, Integer, Unicode, CUnicode, ObjectName, List,
     ForwardDeclaredInstance,
     default, observe,
 )
 
+from typing import Any
+
 
 class DisplayFormatter(Configurable):
 
     active_types = List(Unicode(),
         help="""List of currently active mime-types to display.
         You can use this to set a white-list for formats to display.
         
         Most users will not need to change this value.
         """).tag(config=True)
 
     @default('active_types')
     def _active_types_default(self):
         return self.format_types
 
     @observe('active_types')
     def _active_types_changed(self, change):
         for key, formatter in self.formatters.items():
             if key in change['new']:
                 formatter.enabled = True
             else:
                 formatter.enabled = False
 
     ipython_display_formatter = ForwardDeclaredInstance('FormatterABC')
     @default('ipython_display_formatter')
     def _default_formatter(self):
         return IPythonDisplayFormatter(parent=self)
 
     mimebundle_formatter = ForwardDeclaredInstance('FormatterABC')
     @default('mimebundle_formatter')
     def _default_mime_formatter(self):
         return MimeBundleFormatter(parent=self)
 
     # A dict of formatter whose keys are format types (MIME types) and whose
     # values are subclasses of BaseFormatter.
     formatters = Dict()
     @default('formatters')
     def _formatters_default(self):
         """Activate the default formatters."""
         formatter_classes = [
             PlainTextFormatter,
             HTMLFormatter,
             MarkdownFormatter,
             SVGFormatter,
             PNGFormatter,
             PDFFormatter,
             JPEGFormatter,
             LatexFormatter,
             JSONFormatter,
             JavascriptFormatter
         ]
         d = {}
         for cls in formatter_classes:
             f = cls(parent=self)
             d[f.format_type] = f
         return d
 
     def format(self, obj, include=None, exclude=None):
         """Return a format data dict for an object.
 
         By default all format types will be computed.
 
         The following MIME types are usually implemented:
 
         * text/plain
         * text/html
         * text/markdown
         * text/latex
         * application/json
         * application/javascript
         * application/pdf
         * image/png
         * image/jpeg
         * image/svg+xml
 
         Parameters
         ----------
         obj : object
             The Python object whose format data will be computed.
         include : list, tuple or set; optional
             A list of format type strings (MIME types) to include in the
             format data dict. If this is set *only* the format types included
             in this list will be computed.
         exclude : list, tuple or set; optional
             A list of format type string (MIME types) to exclude in the format
             data dict. If this is set all format types will be computed,
             except for those included in this argument.
             Mimetypes present in exclude will take precedence over the ones in include
 
         Returns
         -------
         (format_dict, metadata_dict) : tuple of two dicts
             format_dict is a dictionary of key/value pairs, one of each format that was
             generated for the object. The keys are the format types, which
             will usually be MIME type strings and the values and JSON'able
             data structure containing the raw data for the representation in
             that format.
 
             metadata_dict is a dictionary of metadata about each mime-type output.
             Its keys will be a strict subset of the keys in format_dict.
 
         Notes
         -----
             If an object implement `_repr_mimebundle_` as well as various
             `_repr_*_`, the data returned by `_repr_mimebundle_` will take
             precedence and the corresponding `_repr_*_` for this mimetype will
             not be called.
 
         """
         format_dict = {}
         md_dict = {}
         
         if self.ipython_display_formatter(obj):
             # object handled itself, don't proceed
             return {}, {}
 
         format_dict, md_dict = self.mimebundle_formatter(obj, include=include, exclude=exclude)
 
         if format_dict or md_dict:
             if include:
                 format_dict = {k:v for k,v in format_dict.items() if k in include}
                 md_dict = {k:v for k,v in md_dict.items() if k in include}
             if exclude:
                 format_dict = {k:v for k,v in format_dict.items() if k not in exclude}
                 md_dict = {k:v for k,v in md_dict.items() if k not in exclude}
 
         for format_type, formatter in self.formatters.items():
             if format_type in format_dict:
                 # already got it from mimebundle, maybe don't render again.
                 # exception: manually registered per-mime renderer
                 # check priority:
                 # 1. user-registered per-mime formatter
                 # 2. mime-bundle (user-registered or repr method)
                 # 3. default per-mime formatter (e.g. repr method)
                 try:
                     formatter.lookup(obj)
                 except KeyError:
                     # no special formatter, use mime-bundle-provided value
                     continue
             if include and format_type not in include:
                 continue
             if exclude and format_type in exclude:
                 continue
             
             md = None
             try:
                 data = formatter(obj)
             except:
                 # FIXME: log the exception
                 raise
             
             # formatters can return raw data or (data, metadata)
             if isinstance(data, tuple) and len(data) == 2:
                 data, md = data
             
             if data is not None:
                 format_dict[format_type] = data
             if md is not None:
                 md_dict[format_type] = md
         return format_dict, md_dict
 
     @property
     def format_types(self):
         """Return the format types (MIME types) of the active formatters."""
         return list(self.formatters.keys())
 
 
 #-----------------------------------------------------------------------------
 # Formatters for specific format types (text, html, svg, etc.)
 #-----------------------------------------------------------------------------
 
 
 def _safe_repr(obj):
     """Try to return a repr of an object
 
     always returns a string, at least.
     """
     try:
         return repr(obj)
     except Exception as e:
         return "un-repr-able object (%r)" % e
 
 
 class FormatterWarning(UserWarning):
     """Warning class for errors in formatters"""
 
 @decorator
 def catch_format_error(method, self, *args, **kwargs):
     """show traceback on failed format call"""
     try:
         r = method(self, *args, **kwargs)
     except NotImplementedError:
         # don't warn on NotImplementedErrors
         return self._check_return(None, args[0])
     except Exception:
         exc_info = sys.exc_info()
         ip = get_ipython()
         if ip is not None:
             ip.showtraceback(exc_info)
         else:
             traceback.print_exception(*exc_info)
         return self._check_return(None, args[0])
     return self._check_return(r, args[0])
 
 
 class FormatterABC(metaclass=abc.ABCMeta):
     """ Abstract base class for Formatters.
 
     A formatter is a callable class that is responsible for computing the
     raw format data for a particular format type (MIME type). For example,
     an HTML formatter would have a format type of `text/html` and would return
     the HTML representation of the object when called.
     """
 
     # The format type of the data returned, usually a MIME type.
     format_type = 'text/plain'
 
     # Is the formatter enabled...
     enabled = True
     
     @abc.abstractmethod
     def __call__(self, obj):
         """Return a JSON'able representation of the object.
 
         If the object cannot be formatted by this formatter,
         warn and return None.
         """
         return repr(obj)
 
 
 def _mod_name_key(typ):
     """Return a (__module__, __name__) tuple for a type.
 
     Used as key in Formatter.deferred_printers.
     """
     module = getattr(typ, '__module__', None)
     name = getattr(typ, '__name__', None)
     return (module, name)
 
 
 def _get_type(obj):
     """Return the type of an instance (old and new-style)"""
     return getattr(obj, '__class__', None) or type(obj)
 
 
 _raise_key_error = Sentinel('_raise_key_error', __name__, 
 """
 Special value to raise a KeyError
 
 Raise KeyError in `BaseFormatter.pop` if passed as the default value to `pop`
 """)
 
 
 class BaseFormatter(Configurable):
     """A base formatter class that is configurable.
 
     This formatter should usually be used as the base class of all formatters.
     It is a traited :class:`Configurable` class and includes an extensible
     API for users to determine how their objects are formatted. The following
     logic is used to find a function to format an given object.
 
     1. The object is introspected to see if it has a method with the name
        :attr:`print_method`. If is does, that object is passed to that method
        for formatting.
     2. If no print method is found, three internal dictionaries are consulted
        to find print method: :attr:`singleton_printers`, :attr:`type_printers`
        and :attr:`deferred_printers`.
 
     Users should use these dictionaries to register functions that will be
     used to compute the format data for their objects (if those objects don't
     have the special print methods). The easiest way of using these
     dictionaries is through the :meth:`for_type` and :meth:`for_type_by_name`
     methods.
 
     If no function/callable is found to compute the format data, ``None`` is
     returned and this format type is not used.
     """
 
-    format_type = Unicode('text/plain')
-    _return_type = str
+    format_type = Unicode("text/plain")
+    _return_type: Any = str
 
     enabled = Bool(True).tag(config=True)
 
     print_method = ObjectName('__repr__')
 
     # The singleton printers.
     # Maps the IDs of the builtin singleton objects to the format functions.
     singleton_printers = Dict().tag(config=True)
 
     # The type-specific printers.
     # Map type objects to the format functions.
     type_printers = Dict().tag(config=True)
 
     # The deferred-import type-specific printers.
     # Map (modulename, classname) pairs to the format functions.
     deferred_printers = Dict().tag(config=True)
     
     @catch_format_error
     def __call__(self, obj):
         """Compute the format for an object."""
         if self.enabled:
             # lookup registered printer
             try:
                 printer = self.lookup(obj)
             except KeyError:
                 pass
             else:
                 return printer(obj)
             # Finally look for special method names
             method = get_real_method(obj, self.print_method)
             if method is not None:
                 return method()
             return None
         else:
             return None
     
     def __contains__(self, typ):
         """map in to lookup_by_type"""
         try:
             self.lookup_by_type(typ)
         except KeyError:
             return False
         else:
             return True
     
     def _check_return(self, r, obj):
         """Check that a return value is appropriate
 
         Return the value if so, None otherwise, warning if invalid.
         """
         if r is None or isinstance(r, self._return_type) or \
             (isinstance(r, tuple) and r and isinstance(r[0], self._return_type)):
             return r
         else:
             warnings.warn(
                 "%s formatter returned invalid type %s (expected %s) for object: %s" % \
                 (self.format_type, type(r), self._return_type, _safe_repr(obj)),
                 FormatterWarning
             )
     
     def lookup(self, obj):
         """Look up the formatter for a given instance.
 
         Parameters
         ----------
         obj : object instance
 
         Returns
         -------
         f : callable
             The registered formatting callable for the type.
 
         Raises
         ------
         KeyError if the type has not been registered.
         """
         # look for singleton first
         obj_id = id(obj)
         if obj_id in self.singleton_printers:
             return self.singleton_printers[obj_id]
         # then lookup by type
         return self.lookup_by_type(_get_type(obj))
     
     def lookup_by_type(self, typ):
         """Look up the registered formatter for a type.
 
         Parameters
         ----------
         typ : type or '__module__.__name__' string for a type
 
         Returns
         -------
         f : callable
             The registered formatting callable for the type.
 
         Raises
         ------
         KeyError if the type has not been registered.
         """
         if isinstance(typ, str):
             typ_key = tuple(typ.rsplit('.',1))
             if typ_key not in self.deferred_printers:
                 # We may have it cached in the type map. We will have to
                 # iterate over all of the types to check.
                 for cls in self.type_printers:
                     if _mod_name_key(cls) == typ_key:
                         return self.type_printers[cls]
             else:
                 return self.deferred_printers[typ_key]
         else:
             for cls in pretty._get_mro(typ):
                 if cls in self.type_printers or self._in_deferred_types(cls):
                     return self.type_printers[cls]
         
         # If we have reached here, the lookup failed.
         raise KeyError("No registered printer for {0!r}".format(typ))
 
     def for_type(self, typ, func=None):
         """Add a format function for a given type.
 
         Parameters
         ----------
         typ : type or '__module__.__name__' string for a type
             The class of the object that will be formatted using `func`.
 
         func : callable
             A callable for computing the format data.
             `func` will be called with the object to be formatted,
             and will return the raw data in this formatter's format.
             Subclasses may use a different call signature for the
             `func` argument.
 
             If `func` is None or not specified, there will be no change,
             only returning the current value.
 
         Returns
         -------
         oldfunc : callable
             The currently registered callable.
             If you are registering a new formatter,
             this will be the previous value (to enable restoring later).
         """
         # if string given, interpret as 'pkg.module.class_name'
         if isinstance(typ, str):
             type_module, type_name = typ.rsplit('.', 1)
             return self.for_type_by_name(type_module, type_name, func)
         
         try:
             oldfunc = self.lookup_by_type(typ)
         except KeyError:
             oldfunc = None
         
         if func is not None:
             self.type_printers[typ] = func
         
         return oldfunc
 
     def for_type_by_name(self, type_module, type_name, func=None):
         """Add a format function for a type specified by the full dotted
         module and name of the type, rather than the type of the object.
 
         Parameters
         ----------
         type_module : str
             The full dotted name of the module the type is defined in, like
             ``numpy``.
 
         type_name : str
             The name of the type (the class name), like ``dtype``
 
         func : callable
             A callable for computing the format data.
             `func` will be called with the object to be formatted,
             and will return the raw data in this formatter's format.
             Subclasses may use a different call signature for the
             `func` argument.
 
             If `func` is None or unspecified, there will be no change,
             only returning the current value.
 
         Returns
         -------
         oldfunc : callable
             The currently registered callable.
             If you are registering a new formatter,
             this will be the previous value (to enable restoring later).
         """
         key = (type_module, type_name)
         
         try:
             oldfunc = self.lookup_by_type("%s.%s" % key)
         except KeyError:
             oldfunc = None
         
         if func is not None:
             self.deferred_printers[key] = func
         return oldfunc
     
     def pop(self, typ, default=_raise_key_error):
         """Pop a formatter for the given type.
 
         Parameters
         ----------
         typ : type or '__module__.__name__' string for a type
         default : object
             value to be returned if no formatter is registered for typ.
 
         Returns
         -------
         obj : object
             The last registered object for the type.
 
         Raises
         ------
         KeyError if the type is not registered and default is not specified.
         """
         
         if isinstance(typ, str):
             typ_key = tuple(typ.rsplit('.',1))
             if typ_key not in self.deferred_printers:
                 # We may have it cached in the type map. We will have to
                 # iterate over all of the types to check.
                 for cls in self.type_printers:
                     if _mod_name_key(cls) == typ_key:
                         old = self.type_printers.pop(cls)
                         break
                 else:
                     old = default
             else:
                 old = self.deferred_printers.pop(typ_key)
         else:
             if typ in self.type_printers:
                 old = self.type_printers.pop(typ)
             else:
                 old = self.deferred_printers.pop(_mod_name_key(typ), default)
         if old is _raise_key_error:
             raise KeyError("No registered value for {0!r}".format(typ))
         return old
 
     def _in_deferred_types(self, cls):
         """
         Check if the given class is specified in the deferred type registry.
 
         Successful matches will be moved to the regular type registry for future use.
         """
         mod = getattr(cls, '__module__', None)
         name = getattr(cls, '__name__', None)
         key = (mod, name)
         if key in self.deferred_printers:
             # Move the printer over to the regular registry.
             printer = self.deferred_printers.pop(key)
             self.type_printers[cls] = printer
             return True
         return False
 
 
 class PlainTextFormatter(BaseFormatter):
     """The default pretty-printer.
 
     This uses :mod:`IPython.lib.pretty` to compute the format data of
     the object. If the object cannot be pretty printed, :func:`repr` is used.
     See the documentation of :mod:`IPython.lib.pretty` for details on
     how to write pretty printers.  Here is a simple example::
 
         def dtype_pprinter(obj, p, cycle):
             if cycle:
                 return p.text('dtype(...)')
             if hasattr(obj, 'fields'):
                 if obj.fields is None:
                     p.text(repr(obj))
                 else:
                     p.begin_group(7, 'dtype([')
                     for i, field in enumerate(obj.descr):
                         if i > 0:
                             p.text(',')
                             p.breakable()
                         p.pretty(field)
                     p.end_group(7, '])')
     """
 
     # The format type of data returned.
     format_type = Unicode('text/plain')
 
     # This subclass ignores this attribute as it always need to return
     # something.
     enabled = Bool(True).tag(config=False)
     
     max_seq_length = Integer(pretty.MAX_SEQ_LENGTH,
         help="""Truncate large collections (lists, dicts, tuples, sets) to this size.
         
         Set to 0 to disable truncation.
         """
     ).tag(config=True)
     
     # Look for a _repr_pretty_ methods to use for pretty printing.
     print_method = ObjectName('_repr_pretty_')
 
     # Whether to pretty-print or not.
     pprint = Bool(True).tag(config=True)
 
     # Whether to be verbose or not.
     verbose = Bool(False).tag(config=True)
 
     # The maximum width.
     max_width = Integer(79).tag(config=True)
 
     # The newline character.
     newline = Unicode('\n').tag(config=True)
 
     # format-string for pprinting floats
     float_format = Unicode('%r')
     # setter for float precision, either int or direct format-string
     float_precision = CUnicode('').tag(config=True)
 
     @observe('float_precision')
     def _float_precision_changed(self, change):
         """float_precision changed, set float_format accordingly.
 
         float_precision can be set by int or str.
         This will set float_format, after interpreting input.
         If numpy has been imported, numpy print precision will also be set.
 
         integer `n` sets format to '%.nf', otherwise, format set directly.
 
         An empty string returns to defaults (repr for float, 8 for numpy).
 
         This parameter can be set via the '%precision' magic.
         """
         new = change['new']
         if '%' in new:
             # got explicit format string
             fmt = new
             try:
                 fmt%3.14159
             except Exception as e:
                 raise ValueError("Precision must be int or format string, not %r"%new) from e
         elif new:
             # otherwise, should be an int
             try:
                 i = int(new)
                 assert i >= 0
             except ValueError as e:
                 raise ValueError("Precision must be int or format string, not %r"%new) from e
             except AssertionError as e:
                 raise ValueError("int precision must be non-negative, not %r"%i) from e
 
             fmt = '%%.%if'%i
             if 'numpy' in sys.modules:
                 # set numpy precision if it has been imported
                 import numpy
                 numpy.set_printoptions(precision=i)
         else:
             # default back to repr
             fmt = '%r'
             if 'numpy' in sys.modules:
                 import numpy
                 # numpy default is 8
                 numpy.set_printoptions(precision=8)
         self.float_format = fmt
 
     # Use the default pretty printers from IPython.lib.pretty.
     @default('singleton_printers')
     def _singleton_printers_default(self):
         return pretty._singleton_pprinters.copy()
 
     @default('type_printers')
     def _type_printers_default(self):
         d = pretty._type_pprinters.copy()
         d[float] = lambda obj,p,cycle: p.text(self.float_format%obj)
         # if NumPy is used, set precision for its float64 type
         if "numpy" in sys.modules:
             import numpy
 
             d[numpy.float64] = lambda obj, p, cycle: p.text(self.float_format % obj)
         return d
 
     @default('deferred_printers')
     def _deferred_printers_default(self):
         return pretty._deferred_type_pprinters.copy()
 
     #### FormatterABC interface ####
 
     @catch_format_error
     def __call__(self, obj):
         """Compute the pretty representation of the object."""
         if not self.pprint:
             return repr(obj)
         else:
             stream = StringIO()
             printer = pretty.RepresentationPrinter(stream, self.verbose,
                 self.max_width, self.newline,
                 max_seq_length=self.max_seq_length,
                 singleton_pprinters=self.singleton_printers,
                 type_pprinters=self.type_printers,
                 deferred_pprinters=self.deferred_printers)
             printer.pretty(obj)
             printer.flush()
             return stream.getvalue()
 
 
 class HTMLFormatter(BaseFormatter):
     """An HTML formatter.
 
     To define the callables that compute the HTML representation of your
     objects, define a :meth:`_repr_html_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     The return value of this formatter should be a valid HTML snippet that
     could be injected into an existing DOM. It should *not* include the
     ```<html>`` or ```<body>`` tags.
     """
     format_type = Unicode('text/html')
 
     print_method = ObjectName('_repr_html_')
 
 
 class MarkdownFormatter(BaseFormatter):
     """A Markdown formatter.
 
     To define the callables that compute the Markdown representation of your
     objects, define a :meth:`_repr_markdown_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     The return value of this formatter should be a valid Markdown.
     """
     format_type = Unicode('text/markdown')
 
     print_method = ObjectName('_repr_markdown_')
 
 class SVGFormatter(BaseFormatter):
     """An SVG formatter.
 
     To define the callables that compute the SVG representation of your
     objects, define a :meth:`_repr_svg_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     The return value of this formatter should be valid SVG enclosed in
     ```<svg>``` tags, that could be injected into an existing DOM. It should
     *not* include the ```<html>`` or ```<body>`` tags.
     """
     format_type = Unicode('image/svg+xml')
 
     print_method = ObjectName('_repr_svg_')
 
 
 class PNGFormatter(BaseFormatter):
     """A PNG formatter.
 
     To define the callables that compute the PNG representation of your
     objects, define a :meth:`_repr_png_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     The return value of this formatter should be raw PNG data, *not*
     base64 encoded.
     """
     format_type = Unicode('image/png')
 
     print_method = ObjectName('_repr_png_')
     
     _return_type = (bytes, str)
 
 
 class JPEGFormatter(BaseFormatter):
     """A JPEG formatter.
 
     To define the callables that compute the JPEG representation of your
     objects, define a :meth:`_repr_jpeg_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     The return value of this formatter should be raw JPEG data, *not*
     base64 encoded.
     """
     format_type = Unicode('image/jpeg')
 
     print_method = ObjectName('_repr_jpeg_')
 
     _return_type = (bytes, str)
 
 
 class LatexFormatter(BaseFormatter):
     """A LaTeX formatter.
 
     To define the callables that compute the LaTeX representation of your
     objects, define a :meth:`_repr_latex_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     The return value of this formatter should be a valid LaTeX equation,
     enclosed in either ```$```, ```$$``` or another LaTeX equation
     environment.
     """
     format_type = Unicode('text/latex')
 
     print_method = ObjectName('_repr_latex_')
 
 
 class JSONFormatter(BaseFormatter):
     """A JSON string formatter.
 
     To define the callables that compute the JSONable representation of
     your objects, define a :meth:`_repr_json_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     The return value of this formatter should be a JSONable list or dict.
     JSON scalars (None, number, string) are not allowed, only dict or list containers.
     """
     format_type = Unicode('application/json')
     _return_type = (list, dict)
 
     print_method = ObjectName('_repr_json_')
     
     def _check_return(self, r, obj):
         """Check that a return value is appropriate
 
         Return the value if so, None otherwise, warning if invalid.
         """
         if r is None:
             return
         md = None
         if isinstance(r, tuple):
             # unpack data, metadata tuple for type checking on first element
             r, md = r
 
         assert not isinstance(
             r, str
         ), "JSON-as-string has been deprecated since IPython < 3"
 
         if md is not None:
             # put the tuple back together
             r = (r, md)
         return super(JSONFormatter, self)._check_return(r, obj)
 
 
 class JavascriptFormatter(BaseFormatter):
     """A Javascript formatter.
 
     To define the callables that compute the Javascript representation of
     your objects, define a :meth:`_repr_javascript_` method or use the
     :meth:`for_type` or :meth:`for_type_by_name` methods to register functions
     that handle this.
 
     The return value of this formatter should be valid Javascript code and
     should *not* be enclosed in ```<script>``` tags.
     """
     format_type = Unicode('application/javascript')
 
     print_method = ObjectName('_repr_javascript_')
 
 
 class PDFFormatter(BaseFormatter):
     """A PDF formatter.
 
     To define the callables that compute the PDF representation of your
     objects, define a :meth:`_repr_pdf_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     The return value of this formatter should be raw PDF data, *not*
     base64 encoded.
     """
     format_type = Unicode('application/pdf')
 
     print_method = ObjectName('_repr_pdf_')
 
     _return_type = (bytes, str)
 
 class IPythonDisplayFormatter(BaseFormatter):
     """An escape-hatch Formatter for objects that know how to display themselves.
     
     To define the callables that compute the representation of your
     objects, define a :meth:`_ipython_display_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this. Unlike mime-type displays, this method should not return anything,
     instead calling any appropriate display methods itself.
     
     This display formatter has highest priority.
     If it fires, no other display formatter will be called.
 
     Prior to IPython 6.1, `_ipython_display_` was the only way to display custom mime-types
     without registering a new Formatter.
     
     IPython 6.1 introduces `_repr_mimebundle_` for displaying custom mime-types,
     so `_ipython_display_` should only be used for objects that require unusual
     display patterns, such as multiple display calls.
     """
     print_method = ObjectName('_ipython_display_')
     _return_type = (type(None), bool)
 
     @catch_format_error
     def __call__(self, obj):
         """Compute the format for an object."""
         if self.enabled:
             # lookup registered printer
             try:
                 printer = self.lookup(obj)
             except KeyError:
                 pass
             else:
                 printer(obj)
                 return True
             # Finally look for special method names
             method = get_real_method(obj, self.print_method)
             if method is not None:
                 method()
                 return True
 
 
 class MimeBundleFormatter(BaseFormatter):
     """A Formatter for arbitrary mime-types.
 
     Unlike other `_repr_<mimetype>_` methods,
     `_repr_mimebundle_` should return mime-bundle data,
     either the mime-keyed `data` dictionary or the tuple `(data, metadata)`.
     Any mime-type is valid.
 
     To define the callables that compute the mime-bundle representation of your
     objects, define a :meth:`_repr_mimebundle_` method or use the :meth:`for_type`
     or :meth:`for_type_by_name` methods to register functions that handle
     this.
 
     .. versionadded:: 6.1
     """
     print_method = ObjectName('_repr_mimebundle_')
     _return_type = dict
     
     def _check_return(self, r, obj):
         r = super(MimeBundleFormatter, self)._check_return(r, obj)
         # always return (data, metadata):
         if r is None:
             return {}, {}
         if not isinstance(r, tuple):
             return r, {}
         return r
 
     @catch_format_error
     def __call__(self, obj, include=None, exclude=None):
         """Compute the format for an object.
 
         Identical to parent's method but we pass extra parameters to the method.
 
         Unlike other _repr_*_ `_repr_mimebundle_` should allow extra kwargs, in
         particular `include` and `exclude`.
         """
         if self.enabled:
             # lookup registered printer
             try:
                 printer = self.lookup(obj)
             except KeyError:
                 pass
             else:
                 return printer(obj)
             # Finally look for special method names
             method = get_real_method(obj, self.print_method)
 
             if method is not None:
                 return method(include=include, exclude=exclude)
             return None
         else:
             return None
 
 
 FormatterABC.register(BaseFormatter)
 FormatterABC.register(PlainTextFormatter)
 FormatterABC.register(HTMLFormatter)
 FormatterABC.register(MarkdownFormatter)
 FormatterABC.register(SVGFormatter)
 FormatterABC.register(PNGFormatter)
 FormatterABC.register(PDFFormatter)
 FormatterABC.register(JPEGFormatter)
 FormatterABC.register(LatexFormatter)
 FormatterABC.register(JSONFormatter)
 FormatterABC.register(JavascriptFormatter)
 FormatterABC.register(IPythonDisplayFormatter)
 FormatterABC.register(MimeBundleFormatter)
 
 
 def format_display_data(obj, include=None, exclude=None):
     """Return a format data dict for an object.
 
     By default all format types will be computed.
 
     Parameters
     ----------
     obj : object
         The Python object whose format data will be computed.
 
     Returns
     -------
     format_dict : dict
         A dictionary of key/value pairs, one or each format that was
         generated for the object. The keys are the format types, which
         will usually be MIME type strings and the values and JSON'able
         data structure containing the raw data for the representation in
         that format.
     include : list or tuple, optional
         A list of format type strings (MIME types) to include in the
         format data dict. If this is set *only* the format types included
         in this list will be computed.
     exclude : list or tuple, optional
         A list of format type string (MIME types) to exclude in the format
         data dict. If this is set all format types will be computed,
         except for those included in this argument.
     """
     from .interactiveshell import InteractiveShell
 
     return InteractiveShell.instance().display_formatter.format(
         obj,
         include,
         exclude
     )

IPython/core/inputsplitter.py

@@ -1,772 +1,773 b''
 """DEPRECATED: Input handling and transformation machinery.
 
 This module was deprecated in IPython 7.0, in favour of inputtransformer2.
 
 The first class in this module, :class:`InputSplitter`, is designed to tell when
 input from a line-oriented frontend is complete and should be executed, and when
 the user should be prompted for another line of code instead. The name 'input
 splitter' is largely for historical reasons.
 
 A companion, :class:`IPythonInputSplitter`, provides the same functionality but
 with full support for the extended IPython syntax (magics, system calls, etc).
 The code to actually do these transformations is in :mod:`IPython.core.inputtransformer`.
 :class:`IPythonInputSplitter` feeds the raw code to the transformers in order
 and stores the results.
 
 For more details, see the class docstrings below.
 """
 
 from warnings import warn
 
 warn('IPython.core.inputsplitter is deprecated since IPython 7 in favor of `IPython.core.inputtransformer2`',
      DeprecationWarning)
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 import ast
 import codeop
 import io
 import re
 import sys
 import tokenize
 import warnings
 
+from typing import List
+
 from IPython.core.inputtransformer import (leading_indent,
                                            classic_prompt,
                                            ipy_prompt,
                                            cellmagic,
                                            assemble_logical_lines,
                                            help_end,
                                            escaped_commands,
                                            assign_from_magic,
                                            assign_from_system,
                                            assemble_python_lines,
                                            )
 
 # These are available in this module for backwards compatibility.
 from IPython.core.inputtransformer import (ESC_SHELL, ESC_SH_CAP, ESC_HELP,
                                         ESC_HELP2, ESC_MAGIC, ESC_MAGIC2,
                                         ESC_QUOTE, ESC_QUOTE2, ESC_PAREN, ESC_SEQUENCES)
 
 #-----------------------------------------------------------------------------
 # Utilities
 #-----------------------------------------------------------------------------
 
 # FIXME: These are general-purpose utilities that later can be moved to the
 # general ward.  Kept here for now because we're being very strict about test
 # coverage with this code, and this lets us ensure that we keep 100% coverage
 # while developing.
 
 # compiled regexps for autoindent management
 dedent_re = re.compile('|'.join([
     r'^\s+raise(\s.*)?$', # raise statement (+ space + other stuff, maybe)
     r'^\s+raise\([^\)]*\).*$', # wacky raise with immediate open paren
     r'^\s+return(\s.*)?$', # normal return (+ space + other stuff, maybe)
     r'^\s+return\([^\)]*\).*$', # wacky return with immediate open paren
     r'^\s+pass\s*$', # pass (optionally followed by trailing spaces)
     r'^\s+break\s*$', # break (optionally followed by trailing spaces)
     r'^\s+continue\s*$', # continue (optionally followed by trailing spaces)
 ]))
 ini_spaces_re = re.compile(r'^([ \t\r\f\v]+)')
 
 # regexp to match pure comment lines so we don't accidentally insert 'if 1:'
 # before pure comments
 comment_line_re = re.compile(r'^\s*\#')
 
 
 def num_ini_spaces(s):
     """Return the number of initial spaces in a string.
 
     Note that tabs are counted as a single space.  For now, we do *not* support
     mixing of tabs and spaces in the user's input.
 
     Parameters
     ----------
     s : string
 
     Returns
     -------
     n : int
     """
 
     ini_spaces = ini_spaces_re.match(s)
     if ini_spaces:
         return ini_spaces.end()
     else:
         return 0
 
 # Fake token types for partial_tokenize:
 INCOMPLETE_STRING = tokenize.N_TOKENS
 IN_MULTILINE_STATEMENT = tokenize.N_TOKENS + 1
 
 # The 2 classes below have the same API as TokenInfo, but don't try to look up
 # a token type name that they won't find.
 class IncompleteString:
     type = exact_type = INCOMPLETE_STRING
     def __init__(self, s, start, end, line):
         self.s = s
         self.start = start
         self.end = end
         self.line = line
 
 class InMultilineStatement:
     type = exact_type = IN_MULTILINE_STATEMENT
     def __init__(self, pos, line):
         self.s = ''
         self.start = self.end = pos
         self.line = line
 
 def partial_tokens(s):
     """Iterate over tokens from a possibly-incomplete string of code.
 
     This adds two special token types: INCOMPLETE_STRING and
     IN_MULTILINE_STATEMENT. These can only occur as the last token yielded, and
     represent the two main ways for code to be incomplete.
     """
     readline = io.StringIO(s).readline
     token = tokenize.TokenInfo(tokenize.NEWLINE, '', (1, 0), (1, 0), '')
     try:
         for token in tokenize.generate_tokens(readline):
             yield token
     except tokenize.TokenError as e:
         # catch EOF error
         lines = s.splitlines(keepends=True)
         end = len(lines), len(lines[-1])
         if 'multi-line string' in e.args[0]:
             l, c = start = token.end
             s = lines[l-1][c:] + ''.join(lines[l:])
             yield IncompleteString(s, start, end, lines[-1])
         elif 'multi-line statement' in e.args[0]:
             yield InMultilineStatement(end, lines[-1])
         else:
             raise
 
 def find_next_indent(code):
     """Find the number of spaces for the next line of indentation"""
     tokens = list(partial_tokens(code))
     if tokens[-1].type == tokenize.ENDMARKER:
         tokens.pop()
     if not tokens:
         return 0
     while (tokens[-1].type in {tokenize.DEDENT, tokenize.NEWLINE, tokenize.COMMENT}):
         tokens.pop()
 
     if tokens[-1].type == INCOMPLETE_STRING:
         # Inside a multiline string
         return 0
 
     # Find the indents used before
     prev_indents = [0]
     def _add_indent(n):
         if n != prev_indents[-1]:
             prev_indents.append(n)
 
     tokiter = iter(tokens)
     for tok in tokiter:
         if tok.type in {tokenize.INDENT, tokenize.DEDENT}:
             _add_indent(tok.end[1])
         elif (tok.type == tokenize.NL):
             try:
                 _add_indent(next(tokiter).start[1])
             except StopIteration:
                 break
 
     last_indent = prev_indents.pop()
 
     # If we've just opened a multiline statement (e.g. 'a = ['), indent more
     if tokens[-1].type == IN_MULTILINE_STATEMENT:
         if tokens[-2].exact_type in {tokenize.LPAR, tokenize.LSQB, tokenize.LBRACE}:
             return last_indent + 4
         return last_indent
 
     if tokens[-1].exact_type == tokenize.COLON:
         # Line ends with colon - indent
         return last_indent + 4
 
     if last_indent:
         # Examine the last line for dedent cues - statements like return or
         # raise which normally end a block of code.
         last_line_starts = 0
         for i, tok in enumerate(tokens):
             if tok.type == tokenize.NEWLINE:
                 last_line_starts = i + 1
 
         last_line_tokens = tokens[last_line_starts:]
         names = [t.string for t in last_line_tokens if t.type == tokenize.NAME]
         if names and names[0] in {'raise', 'return', 'pass', 'break', 'continue'}:
             # Find the most recent indentation less than the current level
             for indent in reversed(prev_indents):
                 if indent < last_indent:
                     return indent
 
     return last_indent
 
 
 def last_blank(src):
     """Determine if the input source ends in a blank.
 
     A blank is either a newline or a line consisting of whitespace.
 
     Parameters
     ----------
     src : string
         A single or multiline string.
     """
     if not src: return False
     ll  = src.splitlines()[-1]
     return (ll == '') or ll.isspace()
 
 
 last_two_blanks_re = re.compile(r'\n\s*\n\s*$', re.MULTILINE)
 last_two_blanks_re2 = re.compile(r'.+\n\s*\n\s+$', re.MULTILINE)
 
 def last_two_blanks(src):
     """Determine if the input source ends in two blanks.
 
     A blank is either a newline or a line consisting of whitespace.
 
     Parameters
     ----------
     src : string
         A single or multiline string.
     """
     if not src: return False
     # The logic here is tricky: I couldn't get a regexp to work and pass all
     # the tests, so I took a different approach: split the source by lines,
     # grab the last two and prepend '###\n' as a stand-in for whatever was in
     # the body before the last two lines.  Then, with that structure, it's
     # possible to analyze with two regexps.  Not the most elegant solution, but
     # it works.  If anyone tries to change this logic, make sure to validate
     # the whole test suite first!
     new_src = '\n'.join(['###\n'] + src.splitlines()[-2:])
     return (bool(last_two_blanks_re.match(new_src)) or
             bool(last_two_blanks_re2.match(new_src)) )
 
 
 def remove_comments(src):
     """Remove all comments from input source.
 
     Note: comments are NOT recognized inside of strings!
 
     Parameters
     ----------
     src : string
         A single or multiline input string.
 
     Returns
     -------
     String with all Python comments removed.
     """
 
     return re.sub('#.*', '', src)
 
 
 def get_input_encoding():
     """Return the default standard input encoding.
 
     If sys.stdin has no encoding, 'ascii' is returned."""
     # There are strange environments for which sys.stdin.encoding is None. We
     # ensure that a valid encoding is returned.
     encoding = getattr(sys.stdin, 'encoding', None)
     if encoding is None:
         encoding = 'ascii'
     return encoding
 
 #-----------------------------------------------------------------------------
 # Classes and functions for normal Python syntax handling
 #-----------------------------------------------------------------------------
 
 class InputSplitter(object):
     r"""An object that can accumulate lines of Python source before execution.
 
     This object is designed to be fed python source line-by-line, using
     :meth:`push`. It will return on each push whether the currently pushed
     code could be executed already. In addition, it provides a method called
     :meth:`push_accepts_more` that can be used to query whether more input
     can be pushed into a single interactive block.
 
     This is a simple example of how an interactive terminal-based client can use
     this tool::
 
         isp = InputSplitter()
         while isp.push_accepts_more():
             indent = ' '*isp.indent_spaces
             prompt = '>>> ' + indent
             line = indent + raw_input(prompt)
             isp.push(line)
         print 'Input source was:\n', isp.source_reset(),
     """
     # A cache for storing the current indentation
     # The first value stores the most recently processed source input
     # The second value is the number of spaces for the current indentation 
     # If self.source matches the first value, the second value is a valid
     # current indentation. Otherwise, the cache is invalid and the indentation
     # must be recalculated.
     _indent_spaces_cache = None, None
     # String, indicating the default input encoding.  It is computed by default
     # at initialization time via get_input_encoding(), but it can be reset by a
     # client with specific knowledge of the encoding.
     encoding = ''
     # String where the current full source input is stored, properly encoded.
     # Reading this attribute is the normal way of querying the currently pushed
     # source code, that has been properly encoded.
     source = ''
     # Code object corresponding to the current source.  It is automatically
     # synced to the source, so it can be queried at any time to obtain the code
     # object; it will be None if the source doesn't compile to valid Python.
     code = None
 
     # Private attributes
 
     # List with lines of input accumulated so far
-    _buffer = None
+    _buffer: List[str]
     # Command compiler
-    _compile = None
+    _compile: codeop.CommandCompiler
     # Boolean indicating whether the current block is complete
     _is_complete = None
     # Boolean indicating whether the current block has an unrecoverable syntax error
     _is_invalid = False
 
-    def __init__(self):
-        """Create a new InputSplitter instance.
-        """
+    def __init__(self) -> None:
+        """Create a new InputSplitter instance."""
         self._buffer = []
         self._compile = codeop.CommandCompiler()
         self.encoding = get_input_encoding()
 
     def reset(self):
         """Reset the input buffer and associated state."""
         self._buffer[:] = []
         self.source = ''
         self.code = None
         self._is_complete = False
         self._is_invalid = False
 
     def source_reset(self):
         """Return the input source and perform a full reset.
         """
         out = self.source
         self.reset()
         return out
 
     def check_complete(self, source):
         """Return whether a block of code is ready to execute, or should be continued
 
         This is a non-stateful API, and will reset the state of this InputSplitter.
 
         Parameters
         ----------
         source : string
             Python input code, which can be multiline.
 
         Returns
         -------
         status : str
             One of 'complete', 'incomplete', or 'invalid' if source is not a
             prefix of valid code.
         indent_spaces : int or None
             The number of spaces by which to indent the next line of code. If
             status is not 'incomplete', this is None.
         """
         self.reset()
         try:
             self.push(source)
         except SyntaxError:
             # Transformers in IPythonInputSplitter can raise SyntaxError,
             # which push() will not catch.
             return 'invalid', None
         else:
             if self._is_invalid:
                 return 'invalid', None
             elif self.push_accepts_more():
                 return 'incomplete', self.get_indent_spaces()
             else:
                 return 'complete', None
         finally:
             self.reset()
 
     def push(self, lines:str) -> bool:
         """Push one or more lines of input.
 
         This stores the given lines and returns a status code indicating
         whether the code forms a complete Python block or not.
 
         Any exceptions generated in compilation are swallowed, but if an
         exception was produced, the method returns True.
 
         Parameters
         ----------
         lines : string
             One or more lines of Python input.
 
         Returns
         -------
         is_complete : boolean
             True if the current input source (the result of the current input
             plus prior inputs) forms a complete Python execution block.  Note that
             this value is also stored as a private attribute (``_is_complete``), so it
             can be queried at any time.
         """
         assert isinstance(lines, str)
         self._store(lines)
         source = self.source
 
         # Before calling _compile(), reset the code object to None so that if an
         # exception is raised in compilation, we don't mislead by having
         # inconsistent code/source attributes.
         self.code, self._is_complete = None, None
         self._is_invalid = False
 
         # Honor termination lines properly
         if source.endswith('\\\n'):
             return False
 
         try:
             with warnings.catch_warnings():
                 warnings.simplefilter('error', SyntaxWarning)
                 self.code = self._compile(source, symbol="exec")
         # Invalid syntax can produce any of a number of different errors from
         # inside the compiler, so we have to catch them all.  Syntax errors
         # immediately produce a 'ready' block, so the invalid Python can be
         # sent to the kernel for evaluation with possible ipython
         # special-syntax conversion.
         except (SyntaxError, OverflowError, ValueError, TypeError,
                 MemoryError, SyntaxWarning):
             self._is_complete = True
             self._is_invalid = True
         else:
             # Compilation didn't produce any exceptions (though it may not have
             # given a complete code object)
             self._is_complete = self.code is not None
 
         return self._is_complete
 
     def push_accepts_more(self):
         """Return whether a block of interactive input can accept more input.
 
         This method is meant to be used by line-oriented frontends, who need to
         guess whether a block is complete or not based solely on prior and
         current input lines.  The InputSplitter considers it has a complete
         interactive block and will not accept more input when either:
 
         * A SyntaxError is raised
 
         * The code is complete and consists of a single line or a single
           non-compound statement
 
         * The code is complete and has a blank line at the end
 
         If the current input produces a syntax error, this method immediately
         returns False but does *not* raise the syntax error exception, as
         typically clients will want to send invalid syntax to an execution
         backend which might convert the invalid syntax into valid Python via
         one of the dynamic IPython mechanisms.
         """
 
         # With incomplete input, unconditionally accept more
         # A syntax error also sets _is_complete to True - see push()
         if not self._is_complete:
             #print("Not complete")  # debug
             return True
         
         # The user can make any (complete) input execute by leaving a blank line
         last_line = self.source.splitlines()[-1]
         if (not last_line) or last_line.isspace():
             #print("Blank line")  # debug
             return False
         
         # If there's just a single line or AST node, and we're flush left, as is
         # the case after a simple statement such as 'a=1', we want to execute it
         # straight away.
         if self.get_indent_spaces() == 0:
             if len(self.source.splitlines()) <= 1:
                 return False
             
             try:
-                code_ast = ast.parse(u''.join(self._buffer))
+                code_ast = ast.parse("".join(self._buffer))
             except Exception:
                 #print("Can't parse AST")  # debug
                 return False
             else:
                 if len(code_ast.body) == 1 and \
                                     not hasattr(code_ast.body[0], 'body'):
                     #print("Simple statement")  # debug
                     return False
 
         # General fallback - accept more code
         return True
 
     def get_indent_spaces(self):
         sourcefor, n = self._indent_spaces_cache
         if sourcefor == self.source:
             return n
 
         # self.source always has a trailing newline
         n = find_next_indent(self.source[:-1])
         self._indent_spaces_cache = (self.source, n)
         return n
 
     # Backwards compatibility. I think all code that used .indent_spaces was
     # inside IPython, but we can leave this here until IPython 7 in case any
     # other modules are using it. -TK, November 2017
     indent_spaces = property(get_indent_spaces)
 
     def _store(self, lines, buffer=None, store='source'):
         """Store one or more lines of input.
 
         If input lines are not newline-terminated, a newline is automatically
         appended."""
 
         if buffer is None:
             buffer = self._buffer
 
         if lines.endswith('\n'):
             buffer.append(lines)
         else:
             buffer.append(lines+'\n')
         setattr(self, store, self._set_source(buffer))
 
     def _set_source(self, buffer):
         return u''.join(buffer)
 
 
 class IPythonInputSplitter(InputSplitter):
     """An input splitter that recognizes all of IPython's special syntax."""
 
     # String with raw, untransformed input.
     source_raw = ''
     
     # Flag to track when a transformer has stored input that it hasn't given
     # back yet.
     transformer_accumulating = False
     
     # Flag to track when assemble_python_lines has stored input that it hasn't
     # given back yet.
     within_python_line = False
 
     # Private attributes
 
     # List with lines of raw input accumulated so far.
     _buffer_raw = None
 
     def __init__(self, line_input_checker=True, physical_line_transforms=None,
                     logical_line_transforms=None, python_line_transforms=None):
         super(IPythonInputSplitter, self).__init__()
         self._buffer_raw = []
         self._validate = True
         
         if physical_line_transforms is not None:
             self.physical_line_transforms = physical_line_transforms
         else:
             self.physical_line_transforms = [
                                              leading_indent(),
                                              classic_prompt(),
                                              ipy_prompt(),
                                              cellmagic(end_on_blank_line=line_input_checker),
                                             ]
         
         self.assemble_logical_lines = assemble_logical_lines()
         if logical_line_transforms is not None:
             self.logical_line_transforms = logical_line_transforms
         else:
             self.logical_line_transforms = [
                                             help_end(),
                                             escaped_commands(),
                                             assign_from_magic(),
                                             assign_from_system(),
                                            ]
         
         self.assemble_python_lines = assemble_python_lines()
         if python_line_transforms is not None:
             self.python_line_transforms = python_line_transforms
         else:
             # We don't use any of these at present
             self.python_line_transforms = []
     
     @property
     def transforms(self):
         "Quick access to all transformers."
         return self.physical_line_transforms + \
             [self.assemble_logical_lines] + self.logical_line_transforms + \
             [self.assemble_python_lines]  + self.python_line_transforms
     
     @property
     def transforms_in_use(self):
         """Transformers, excluding logical line transformers if we're in a
         Python line."""
         t = self.physical_line_transforms[:]
         if not self.within_python_line:
             t += [self.assemble_logical_lines] + self.logical_line_transforms
         return t + [self.assemble_python_lines] + self.python_line_transforms
 
     def reset(self):
         """Reset the input buffer and associated state."""
         super(IPythonInputSplitter, self).reset()
         self._buffer_raw[:] = []
         self.source_raw = ''
         self.transformer_accumulating = False
         self.within_python_line = False
 
         for t in self.transforms:
             try:
                 t.reset()
             except SyntaxError:
                 # Nothing that calls reset() expects to handle transformer
                 # errors
                 pass
     
     def flush_transformers(self):
         def _flush(transform, outs):
             """yield transformed lines
 
             always strings, never None
 
             transform: the current transform
             outs: an iterable of previously transformed inputs.
                  Each may be multiline, which will be passed
                  one line at a time to transform.
             """
             for out in outs:
                 for line in out.splitlines():
                     # push one line at a time
                     tmp = transform.push(line)
                     if tmp is not None:
                         yield tmp
             
             # reset the transform
             tmp = transform.reset()
             if tmp is not None:
                 yield tmp
         
         out = []
         for t in self.transforms_in_use:
             out = _flush(t, out)
         
         out = list(out)
         if out:
             self._store('\n'.join(out))
 
     def raw_reset(self):
         """Return raw input only and perform a full reset.
         """
         out = self.source_raw
         self.reset()
         return out
     
     def source_reset(self):
         try:
             self.flush_transformers()
             return self.source
         finally:
             self.reset()
 
     def push_accepts_more(self):
         if self.transformer_accumulating:
             return True
         else:
             return super(IPythonInputSplitter, self).push_accepts_more()
 
     def transform_cell(self, cell):
         """Process and translate a cell of input.
         """
         self.reset()
         try:
             self.push(cell)
             self.flush_transformers()
             return self.source
         finally:
             self.reset()
 
     def push(self, lines:str) -> bool:
         """Push one or more lines of IPython input.
 
         This stores the given lines and returns a status code indicating
         whether the code forms a complete Python block or not, after processing
         all input lines for special IPython syntax.
 
         Any exceptions generated in compilation are swallowed, but if an
         exception was produced, the method returns True.
 
         Parameters
         ----------
         lines : string
             One or more lines of Python input.
 
         Returns
         -------
         is_complete : boolean
             True if the current input source (the result of the current input
             plus prior inputs) forms a complete Python execution block.  Note that
             this value is also stored as a private attribute (_is_complete), so it
             can be queried at any time.
         """
         assert isinstance(lines, str)
         # We must ensure all input is pure unicode
         # ''.splitlines() --> [], but we need to push the empty line to transformers
         lines_list = lines.splitlines()
         if not lines_list:
             lines_list = ['']
 
         # Store raw source before applying any transformations to it.  Note
         # that this must be done *after* the reset() call that would otherwise
         # flush the buffer.
         self._store(lines, self._buffer_raw, 'source_raw')
 
         transformed_lines_list = []
         for line in lines_list:
             transformed = self._transform_line(line)
             if transformed is not None:
                 transformed_lines_list.append(transformed)
 
         if transformed_lines_list:
             transformed_lines = '\n'.join(transformed_lines_list)
             return super(IPythonInputSplitter, self).push(transformed_lines)
         else:
             # Got nothing back from transformers - they must be waiting for
             # more input.
             return False
 
     def _transform_line(self, line):
         """Push a line of input code through the various transformers.
 
         Returns any output from the transformers, or None if a transformer
         is accumulating lines.
 
         Sets self.transformer_accumulating as a side effect.
         """
         def _accumulating(dbg):
             #print(dbg)
             self.transformer_accumulating = True
             return None
 
         for transformer in self.physical_line_transforms:
             line = transformer.push(line)
             if line is None:
                 return _accumulating(transformer)
 
         if not self.within_python_line:
             line = self.assemble_logical_lines.push(line)
             if line is None:
                 return _accumulating('acc logical line')
 
             for transformer in self.logical_line_transforms:
                 line = transformer.push(line)
                 if line is None:
                     return _accumulating(transformer)
 
         line = self.assemble_python_lines.push(line)
         if line is None:
             self.within_python_line = True
             return _accumulating('acc python line')
         else:
             self.within_python_line = False
 
         for transformer in self.python_line_transforms:
             line = transformer.push(line)
             if line is None:
                 return _accumulating(transformer)
 
         #print("transformers clear") #debug
         self.transformer_accumulating = False
         return line
 

IPython/core/magic_arguments.py

@@ -1,310 +1,310 b''
 ''' A decorator-based method of constructing IPython magics with `argparse`
 option handling.
 
 New magic functions can be defined like so::
 
     from IPython.core.magic_arguments import (argument, magic_arguments,
         parse_argstring)
 
     @magic_arguments()
     @argument('-o', '--option', help='An optional argument.')
     @argument('arg', type=int, help='An integer positional argument.')
     def magic_cool(self, arg):
         """ A really cool magic command.
 
     """
         args = parse_argstring(magic_cool, arg)
         ...
 
 The `@magic_arguments` decorator marks the function as having argparse arguments.
 The `@argument` decorator adds an argument using the same syntax as argparse's
 `add_argument()` method. More sophisticated uses may also require the
 `@argument_group` or `@kwds` decorator to customize the formatting and the
 parsing.
 
 Help text for the magic is automatically generated from the docstring and the
 arguments::
 
     In[1]: %cool?
         %cool [-o OPTION] arg
         
         A really cool magic command.
         
         positional arguments:
           arg                   An integer positional argument.
         
         optional arguments:
           -o OPTION, --option OPTION
                                 An optional argument.
 
 Here is an elaborated example that uses default parameters in `argument` and calls the `args` in the cell magic::
 
     from IPython.core.magic import register_cell_magic
     from IPython.core.magic_arguments import (argument, magic_arguments,
                                             parse_argstring)
 
 
     @magic_arguments()
     @argument(
         "--option",
         "-o",
         help=("Add an option here"),
     )
     @argument(
         "--style",
         "-s",
         default="foo",
         help=("Add some style arguments"),
     )
     @register_cell_magic
     def my_cell_magic(line, cell):
         args = parse_argstring(my_cell_magic, line)
         print(f"{args.option=}")
         print(f"{args.style=}")
         print(f"{cell=}")
 
 In a jupyter notebook, this cell magic can be executed like this::
 
     %%my_cell_magic -o Hello
     print("bar")
     i = 42
 
 Inheritance diagram:
 
 .. inheritance-diagram:: IPython.core.magic_arguments
    :parts: 3
 
 '''
 #-----------------------------------------------------------------------------
 # Copyright (C) 2010-2011, IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 import argparse
 import re
 
 # Our own imports
 from IPython.core.error import UsageError
 from IPython.utils.decorators import undoc
 from IPython.utils.process import arg_split
 from IPython.utils.text import dedent
 
 NAME_RE = re.compile(r"[a-zA-Z][a-zA-Z0-9_-]*$")
 
 @undoc
 class MagicHelpFormatter(argparse.RawDescriptionHelpFormatter):
     """A HelpFormatter with a couple of changes to meet our needs.
     """
     # Modified to dedent text.
     def _fill_text(self, text, width, indent):
         return argparse.RawDescriptionHelpFormatter._fill_text(self, dedent(text), width, indent)
 
     # Modified to wrap argument placeholders in <> where necessary.
     def _format_action_invocation(self, action):
         if not action.option_strings:
             metavar, = self._metavar_formatter(action, action.dest)(1)
             return metavar
 
         else:
             parts = []
 
             # if the Optional doesn't take a value, format is:
             #    -s, --long
             if action.nargs == 0:
                 parts.extend(action.option_strings)
 
             # if the Optional takes a value, format is:
             #    -s ARGS, --long ARGS
             else:
                 default = action.dest.upper()
                 args_string = self._format_args(action, default)
                 # IPYTHON MODIFICATION: If args_string is not a plain name, wrap
                 # it in <> so it's valid RST.
                 if not NAME_RE.match(args_string):
                     args_string = "<%s>" % args_string
                 for option_string in action.option_strings:
                     parts.append('%s %s' % (option_string, args_string))
 
             return ', '.join(parts)
 
     # Override the default prefix ('usage') to our % magic escape,
     # in a code block.
     def add_usage(self, usage, actions, groups, prefix="::\n\n  %"):
         super(MagicHelpFormatter, self).add_usage(usage, actions, groups, prefix)
 
 class MagicArgumentParser(argparse.ArgumentParser):
     """ An ArgumentParser tweaked for use by IPython magics.
     """
     def __init__(self,
                  prog=None,
                  usage=None,
                  description=None,
                  epilog=None,
                  parents=None,
                  formatter_class=MagicHelpFormatter,
                  prefix_chars='-',
                  argument_default=None,
                  conflict_handler='error',
                  add_help=False):
         if parents is None:
             parents = []
         super(MagicArgumentParser, self).__init__(prog=prog, usage=usage,
             description=description, epilog=epilog,
             parents=parents, formatter_class=formatter_class,
             prefix_chars=prefix_chars, argument_default=argument_default,
             conflict_handler=conflict_handler, add_help=add_help)
 
     def error(self, message):
         """ Raise a catchable error instead of exiting.
         """
         raise UsageError(message)
 
     def parse_argstring(self, argstring):
         """ Split a string into an argument list and parse that argument list.
         """
         argv = arg_split(argstring)
         return self.parse_args(argv)
 
 
 def construct_parser(magic_func):
     """ Construct an argument parser using the function decorations.
     """
     kwds = getattr(magic_func, 'argcmd_kwds', {})
     if 'description' not in kwds:
         kwds['description'] = getattr(magic_func, '__doc__', None)
     arg_name = real_name(magic_func)
     parser = MagicArgumentParser(arg_name, **kwds)
     # Reverse the list of decorators in order to apply them in the
     # order in which they appear in the source.
     group = None
     for deco in magic_func.decorators[::-1]:
         result = deco.add_to_parser(parser, group)
         if result is not None:
             group = result
 
     # Replace the magic function's docstring with the full help text.
     magic_func.__doc__ = parser.format_help()
 
     return parser
 
 
 def parse_argstring(magic_func, argstring):
     """ Parse the string of arguments for the given magic function.
     """
     return magic_func.parser.parse_argstring(argstring)
 
 
 def real_name(magic_func):
     """ Find the real name of the magic.
     """
     magic_name = magic_func.__name__
     if magic_name.startswith('magic_'):
         magic_name = magic_name[len('magic_'):]
     return getattr(magic_func, 'argcmd_name', magic_name)
 
 
 class ArgDecorator(object):
     """ Base class for decorators to add ArgumentParser information to a method.
     """
 
     def __call__(self, func):
         if not getattr(func, 'has_arguments', False):
             func.has_arguments = True
             func.decorators = []
         func.decorators.append(self)
         return func
 
     def add_to_parser(self, parser, group):
         """ Add this object's information to the parser, if necessary.
         """
         pass
 
 
 class magic_arguments(ArgDecorator):
     """ Mark the magic as having argparse arguments and possibly adjust the
     name.
     """
 
     def __init__(self, name=None):
         self.name = name
 
     def __call__(self, func):
         if not getattr(func, 'has_arguments', False):
             func.has_arguments = True
             func.decorators = []
         if self.name is not None:
             func.argcmd_name = self.name
         # This should be the first decorator in the list of decorators, thus the
         # last to execute. Build the parser.
         func.parser = construct_parser(func)
         return func
 
 
 class ArgMethodWrapper(ArgDecorator):
 
     """
     Base class to define a wrapper for ArgumentParser method.
 
     Child class must define either `_method_name` or `add_to_parser`.
 
     """
 
-    _method_name = None
+    _method_name: str
 
     def __init__(self, *args, **kwds):
         self.args = args
         self.kwds = kwds
 
     def add_to_parser(self, parser, group):
         """ Add this object's information to the parser.
         """
         if group is not None:
             parser = group
         getattr(parser, self._method_name)(*self.args, **self.kwds)
         return None
 
 
 class argument(ArgMethodWrapper):
     """ Store arguments and keywords to pass to add_argument().
 
     Instances also serve to decorate command methods.
     """
     _method_name = 'add_argument'
 
 
 class defaults(ArgMethodWrapper):
     """ Store arguments and keywords to pass to set_defaults().
 
     Instances also serve to decorate command methods.
     """
     _method_name = 'set_defaults'
 
 
 class argument_group(ArgMethodWrapper):
     """ Store arguments and keywords to pass to add_argument_group().
 
     Instances also serve to decorate command methods.
     """
 
     def add_to_parser(self, parser, group):
         """ Add this object's information to the parser.
         """
         return parser.add_argument_group(*self.args, **self.kwds)
 
 
 class kwds(ArgDecorator):
     """ Provide other keywords to the sub-parser constructor.
     """
     def __init__(self, **kwds):
         self.kwds = kwds
 
     def __call__(self, func):
         func = super(kwds, self).__call__(func)
         func.argcmd_kwds = self.kwds
         return func
 
 
 __all__ = ['magic_arguments', 'argument', 'argument_group', 'kwds',
     'parse_argstring']

IPython/core/oinspect.py

@@ -1,1093 +1,1098 b''
 # -*- coding: utf-8 -*-
 """Tools for inspecting Python objects.
 
 Uses syntax highlighting for presenting the various information elements.
 
 Similar in spirit to the inspect module, but all calls take a name argument to
 reference the name under which an object is being read.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 __all__ = ['Inspector','InspectColors']
 
 # stdlib modules
 import ast
 import inspect
 from inspect import signature
 import html
 import linecache
 import warnings
 import os
 from textwrap import dedent
 import types
 import io as stdlib_io
 
 from typing import Union
 
 # IPython's own
 from IPython.core import page
 from IPython.lib.pretty import pretty
 from IPython.testing.skipdoctest import skip_doctest
 from IPython.utils import PyColorize
 from IPython.utils import openpy
 from IPython.utils.dir2 import safe_hasattr
 from IPython.utils.path import compress_user
 from IPython.utils.text import indent
 from IPython.utils.wildcard import list_namespace
 from IPython.utils.wildcard import typestr2type
 from IPython.utils.coloransi import TermColors, ColorScheme, ColorSchemeTable
 from IPython.utils.py3compat import cast_unicode
 from IPython.utils.colorable import Colorable
 from IPython.utils.decorators import undoc
 
 from pygments import highlight
 from pygments.lexers import PythonLexer
 from pygments.formatters import HtmlFormatter
 
-from typing import Any
+from typing import Any, Optional
 from dataclasses import dataclass
 
 
 @dataclass
 class OInfo:
     ismagic: bool
     isalias: bool
     found: bool
-    namespace: str
+    namespace: Optional[str]
     parent: Any
     obj: Any
 
 def pylight(code):
     return highlight(code, PythonLexer(), HtmlFormatter(noclasses=True))
 
 # builtin docstrings to ignore
 _func_call_docstring = types.FunctionType.__call__.__doc__
 _object_init_docstring = object.__init__.__doc__
 _builtin_type_docstrings = {
     inspect.getdoc(t) for t in (types.ModuleType, types.MethodType,
                                 types.FunctionType, property)
 }
 
 _builtin_func_type = type(all)
 _builtin_meth_type = type(str.upper)  # Bound methods have the same type as builtin functions
 #****************************************************************************
 # Builtin color schemes
 
 Colors = TermColors  # just a shorthand
 
 InspectColors = PyColorize.ANSICodeColors
 
 #****************************************************************************
 # Auxiliary functions and objects
 
 # See the messaging spec for the definition of all these fields.  This list
 # effectively defines the order of display
 info_fields = ['type_name', 'base_class', 'string_form', 'namespace',
                'length', 'file', 'definition', 'docstring', 'source',
                'init_definition', 'class_docstring', 'init_docstring',
                'call_def', 'call_docstring',
                # These won't be printed but will be used to determine how to
                # format the object
                'ismagic', 'isalias', 'isclass', 'found', 'name'
                ]
 
 
 def object_info(**kw):
     """Make an object info dict with all fields present."""
     infodict = {k:None for k in info_fields}
     infodict.update(kw)
     return infodict
 
 
 def get_encoding(obj):
     """Get encoding for python source file defining obj
 
     Returns None if obj is not defined in a sourcefile.
     """
     ofile = find_file(obj)
     # run contents of file through pager starting at line where the object
     # is defined, as long as the file isn't binary and is actually on the
     # filesystem.
     if ofile is None:
         return None
     elif ofile.endswith(('.so', '.dll', '.pyd')):
         return None
     elif not os.path.isfile(ofile):
         return None
     else:
         # Print only text files, not extension binaries.  Note that
         # getsourcelines returns lineno with 1-offset and page() uses
         # 0-offset, so we must adjust.
         with stdlib_io.open(ofile, 'rb') as buffer:   # Tweaked to use io.open for Python 2
             encoding, lines = openpy.detect_encoding(buffer.readline)
         return encoding
 
 def getdoc(obj) -> Union[str,None]:
     """Stable wrapper around inspect.getdoc.
 
     This can't crash because of attribute problems.
 
     It also attempts to call a getdoc() method on the given object.  This
     allows objects which provide their docstrings via non-standard mechanisms
     (like Pyro proxies) to still be inspected by ipython's ? system.
     """
     # Allow objects to offer customized documentation via a getdoc method:
     try:
         ds = obj.getdoc()
     except Exception:
         pass
     else:
         if isinstance(ds, str):
             return inspect.cleandoc(ds)
     docstr = inspect.getdoc(obj)
     return docstr
 
 
 def getsource(obj, oname='') -> Union[str,None]:
     """Wrapper around inspect.getsource.
 
     This can be modified by other projects to provide customized source
     extraction.
 
     Parameters
     ----------
     obj : object
         an object whose source code we will attempt to extract
     oname : str
         (optional) a name under which the object is known
 
     Returns
     -------
     src : unicode or None
 
     """
 
     if isinstance(obj, property):
         sources = []
         for attrname in ['fget', 'fset', 'fdel']:
             fn = getattr(obj, attrname)
             if fn is not None:
                 encoding = get_encoding(fn)
                 oname_prefix = ('%s.' % oname) if oname else ''
                 sources.append(''.join(('# ', oname_prefix, attrname)))
                 if inspect.isfunction(fn):
-                    sources.append(dedent(getsource(fn)))
+                    _src = getsource(fn)
+                    if _src:
+                        # assert _src is not None, "please mypy"
+                        sources.append(dedent(_src))
                 else:
                     # Default str/repr only prints function name,
                     # pretty.pretty prints module name too.
                     sources.append(
                         '%s%s = %s\n' % (oname_prefix, attrname, pretty(fn))
                     )
         if sources:
             return '\n'.join(sources)
         else:
             return None
 
     else:
         # Get source for non-property objects.
 
         obj = _get_wrapped(obj)
 
         try:
             src = inspect.getsource(obj)
         except TypeError:
             # The object itself provided no meaningful source, try looking for
             # its class definition instead.
             try:
                 src = inspect.getsource(obj.__class__)
             except (OSError, TypeError):
                 return None
         except OSError:
             return None
 
         return src
 
 
 def is_simple_callable(obj):
     """True if obj is a function ()"""
     return (inspect.isfunction(obj) or inspect.ismethod(obj) or \
             isinstance(obj, _builtin_func_type) or isinstance(obj, _builtin_meth_type))
 
 @undoc
 def getargspec(obj):
     """Wrapper around :func:`inspect.getfullargspec`
 
     In addition to functions and methods, this can also handle objects with a
     ``__call__`` attribute.
 
     DEPRECATED: Deprecated since 7.10. Do not use, will be removed.
     """
 
     warnings.warn('`getargspec` function is deprecated as of IPython 7.10'
                   'and will be removed in future versions.', DeprecationWarning, stacklevel=2)
 
     if safe_hasattr(obj, '__call__') and not is_simple_callable(obj):
         obj = obj.__call__
 
     return inspect.getfullargspec(obj)
 
 @undoc
 def format_argspec(argspec):
     """Format argspect, convenience wrapper around inspect's.
 
     This takes a dict instead of ordered arguments and calls
     inspect.format_argspec with the arguments in the necessary order.
 
     DEPRECATED (since 7.10): Do not use; will be removed in future versions.
     """
     
     warnings.warn('`format_argspec` function is deprecated as of IPython 7.10'
                   'and will be removed in future versions.', DeprecationWarning, stacklevel=2)
 
 
     return inspect.formatargspec(argspec['args'], argspec['varargs'],
                                  argspec['varkw'], argspec['defaults'])
 
 @undoc
 def call_tip(oinfo, format_call=True):
     """DEPRECATED since 6.0. Extract call tip data from an oinfo dict."""
     warnings.warn(
         "`call_tip` function is deprecated as of IPython 6.0"
         "and will be removed in future versions.",
         DeprecationWarning,
         stacklevel=2,
     )
     # Get call definition
     argspec = oinfo.get('argspec')
     if argspec is None:
         call_line = None
     else:
         # Callable objects will have 'self' as their first argument, prune
         # it out if it's there for clarity (since users do *not* pass an
         # extra first argument explicitly).
         try:
             has_self = argspec['args'][0] == 'self'
         except (KeyError, IndexError):
             pass
         else:
             if has_self:
                 argspec['args'] = argspec['args'][1:]
 
         call_line = oinfo['name']+format_argspec(argspec)
 
     # Now get docstring.
     # The priority is: call docstring, constructor docstring, main one.
     doc = oinfo.get('call_docstring')
     if doc is None:
         doc = oinfo.get('init_docstring')
     if doc is None:
         doc = oinfo.get('docstring','')
 
     return call_line, doc
 
 
 def _get_wrapped(obj):
     """Get the original object if wrapped in one or more @decorators
 
     Some objects automatically construct similar objects on any unrecognised
     attribute access (e.g. unittest.mock.call). To protect against infinite loops,
     this will arbitrarily cut off after 100 levels of obj.__wrapped__
     attribute access. --TK, Jan 2016
     """
     orig_obj = obj
     i = 0
     while safe_hasattr(obj, '__wrapped__'):
         obj = obj.__wrapped__
         i += 1
         if i > 100:
             # __wrapped__ is probably a lie, so return the thing we started with
             return orig_obj
     return obj
 
 def find_file(obj) -> str:
     """Find the absolute path to the file where an object was defined.
 
     This is essentially a robust wrapper around `inspect.getabsfile`.
 
     Returns None if no file can be found.
 
     Parameters
     ----------
     obj : any Python object
 
     Returns
     -------
     fname : str
         The absolute path to the file where the object was defined.
     """
     obj = _get_wrapped(obj)
 
     fname = None
     try:
         fname = inspect.getabsfile(obj)
     except TypeError:
         # For an instance, the file that matters is where its class was
         # declared.
         try:
             fname = inspect.getabsfile(obj.__class__)
         except (OSError, TypeError):
             # Can happen for builtins
             pass
     except OSError:
         pass
 
     return cast_unicode(fname)
 
 
 def find_source_lines(obj):
     """Find the line number in a file where an object was defined.
 
     This is essentially a robust wrapper around `inspect.getsourcelines`.
 
     Returns None if no file can be found.
 
     Parameters
     ----------
     obj : any Python object
 
     Returns
     -------
     lineno : int
         The line number where the object definition starts.
     """
     obj = _get_wrapped(obj)
 
     try:
         lineno = inspect.getsourcelines(obj)[1]
     except TypeError:
         # For instances, try the class object like getsource() does
         try:
             lineno = inspect.getsourcelines(obj.__class__)[1]
         except (OSError, TypeError):
             return None
     except OSError:
         return None
 
     return lineno
 
 class Inspector(Colorable):
 
     def __init__(self, color_table=InspectColors,
                  code_color_table=PyColorize.ANSICodeColors,
                  scheme=None,
                  str_detail_level=0,
                  parent=None, config=None):
         super(Inspector, self).__init__(parent=parent, config=config)
         self.color_table = color_table
         self.parser = PyColorize.Parser(out='str', parent=self, style=scheme)
         self.format = self.parser.format
         self.str_detail_level = str_detail_level
         self.set_active_scheme(scheme)
 
     def _getdef(self,obj,oname='') -> Union[str,None]:
         """Return the call signature for any callable object.
 
         If any exception is generated, None is returned instead and the
         exception is suppressed."""
         try:
             return _render_signature(signature(obj), oname)
         except:
             return None
 
     def __head(self,h) -> str:
         """Return a header string with proper colors."""
         return '%s%s%s' % (self.color_table.active_colors.header,h,
                            self.color_table.active_colors.normal)
 
     def set_active_scheme(self, scheme):
         if scheme is not None:
             self.color_table.set_active_scheme(scheme)
             self.parser.color_table.set_active_scheme(scheme)
 
     def noinfo(self, msg, oname):
         """Generic message when no information is found."""
         print('No %s found' % msg, end=' ')
         if oname:
             print('for %s' % oname)
         else:
             print()
 
     def pdef(self, obj, oname=''):
         """Print the call signature for any callable object.
 
         If the object is a class, print the constructor information."""
 
         if not callable(obj):
             print('Object is not callable.')
             return
 
         header = ''
 
         if inspect.isclass(obj):
             header = self.__head('Class constructor information:\n')
 
 
         output = self._getdef(obj,oname)
         if output is None:
             self.noinfo('definition header',oname)
         else:
             print(header,self.format(output), end=' ')
 
     # In Python 3, all classes are new-style, so they all have __init__.
     @skip_doctest
     def pdoc(self, obj, oname='', formatter=None):
         """Print the docstring for any object.
 
         Optional:
         -formatter: a function to run the docstring through for specially
         formatted docstrings.
 
         Examples
         --------
         In [1]: class NoInit:
            ...:     pass
 
         In [2]: class NoDoc:
            ...:     def __init__(self):
            ...:         pass
 
         In [3]: %pdoc NoDoc
         No documentation found for NoDoc
 
         In [4]: %pdoc NoInit
         No documentation found for NoInit
 
         In [5]: obj = NoInit()
 
         In [6]: %pdoc obj
         No documentation found for obj
 
         In [5]: obj2 = NoDoc()
 
         In [6]: %pdoc obj2
         No documentation found for obj2
         """
 
         head = self.__head  # For convenience
         lines = []
         ds = getdoc(obj)
         if formatter:
             ds = formatter(ds).get('plain/text', ds)
         if ds:
             lines.append(head("Class docstring:"))
             lines.append(indent(ds))
         if inspect.isclass(obj) and hasattr(obj, '__init__'):
             init_ds = getdoc(obj.__init__)
             if init_ds is not None:
                 lines.append(head("Init docstring:"))
                 lines.append(indent(init_ds))
         elif hasattr(obj,'__call__'):
             call_ds = getdoc(obj.__call__)
             if call_ds:
                 lines.append(head("Call docstring:"))
                 lines.append(indent(call_ds))
 
         if not lines:
             self.noinfo('documentation',oname)
         else:
             page.page('\n'.join(lines))
 
     def psource(self, obj, oname=''):
         """Print the source code for an object."""
 
         # Flush the source cache because inspect can return out-of-date source
         linecache.checkcache()
         try:
             src = getsource(obj, oname=oname)
         except Exception:
             src = None
 
         if src is None:
             self.noinfo('source', oname)
         else:
             page.page(self.format(src))
 
     def pfile(self, obj, oname=''):
         """Show the whole file where an object was defined."""
 
         lineno = find_source_lines(obj)
         if lineno is None:
             self.noinfo('file', oname)
             return
 
         ofile = find_file(obj)
         # run contents of file through pager starting at line where the object
         # is defined, as long as the file isn't binary and is actually on the
         # filesystem.
         if ofile.endswith(('.so', '.dll', '.pyd')):
             print('File %r is binary, not printing.' % ofile)
         elif not os.path.isfile(ofile):
             print('File %r does not exist, not printing.' % ofile)
         else:
             # Print only text files, not extension binaries.  Note that
             # getsourcelines returns lineno with 1-offset and page() uses
             # 0-offset, so we must adjust.
             page.page(self.format(openpy.read_py_file(ofile, skip_encoding_cookie=False)), lineno - 1)
 
 
     def _mime_format(self, text:str, formatter=None) -> dict:
         """Return a mime bundle representation of the input text.
 
         - if `formatter` is None, the returned mime bundle has
            a ``text/plain`` field, with the input text.
            a ``text/html`` field with a ``<pre>`` tag containing the input text.
 
         - if ``formatter`` is not None, it must be a callable transforming the
           input text into a mime bundle. Default values for ``text/plain`` and
           ``text/html`` representations are the ones described above.
 
         Note:
 
         Formatters returning strings are supported but this behavior is deprecated.
 
         """
         defaults = {
             "text/plain": text,
             "text/html": f"<pre>{html.escape(text)}</pre>",
         }
 
         if formatter is None:
             return defaults
         else:
             formatted = formatter(text)
 
             if not isinstance(formatted, dict):
                 # Handle the deprecated behavior of a formatter returning
                 # a string instead of a mime bundle.
                 return {"text/plain": formatted, "text/html": f"<pre>{formatted}</pre>"}
 
             else:
                 return dict(defaults, **formatted)
 
 
     def format_mime(self, bundle):
         """Format a mimebundle being created by _make_info_unformatted into a real mimebundle"""
         # Format text/plain mimetype
         if isinstance(bundle["text/plain"], (list, tuple)):
             # bundle['text/plain'] is a list of (head, formatted body) pairs
             lines = []
             _len = max(len(h) for h, _ in bundle["text/plain"])
 
             for head, body in bundle["text/plain"]:
                 body = body.strip("\n")
                 delim = "\n" if "\n" in body else " "
                 lines.append(
                     f"{self.__head(head+':')}{(_len - len(head))*' '}{delim}{body}"
                 )
 
             bundle["text/plain"] = "\n".join(lines)
 
         # Format the text/html mimetype
         if isinstance(bundle["text/html"], (list, tuple)):
             # bundle['text/html'] is a list of (head, formatted body) pairs
             bundle["text/html"] = "\n".join(
                 (f"<h1>{head}</h1>\n{body}" for (head, body) in bundle["text/html"])
             )
         return bundle
 
     def _append_info_field(
         self, bundle, title: str, key: str, info, omit_sections, formatter
     ):
         """Append an info value to the unformatted mimebundle being constructed by _make_info_unformatted"""
         if title in omit_sections or key in omit_sections:
             return
         field = info[key]
         if field is not None:
             formatted_field = self._mime_format(field, formatter)
             bundle["text/plain"].append((title, formatted_field["text/plain"]))
             bundle["text/html"].append((title, formatted_field["text/html"]))
 
     def _make_info_unformatted(self, obj, info, formatter, detail_level, omit_sections):
         """Assemble the mimebundle as unformatted lists of information"""
         bundle = {
             "text/plain": [],
             "text/html": [],
         }
 
         # A convenience function to simplify calls below
         def append_field(bundle, title: str, key: str, formatter=None):
             self._append_info_field(
                 bundle,
                 title=title,
                 key=key,
                 info=info,
                 omit_sections=omit_sections,
                 formatter=formatter,
             )
 
         def code_formatter(text):
             return {
                 'text/plain': self.format(text),
                 'text/html': pylight(text)
             }
 
         if info["isalias"]:
             append_field(bundle, "Repr", "string_form")
 
         elif info['ismagic']:
             if detail_level > 0:
                 append_field(bundle, "Source", "source", code_formatter)
             else:
                 append_field(bundle, "Docstring", "docstring", formatter)
             append_field(bundle, "File", "file")
 
         elif info['isclass'] or is_simple_callable(obj):
             # Functions, methods, classes
             append_field(bundle, "Signature", "definition", code_formatter)
             append_field(bundle, "Init signature", "init_definition", code_formatter)
             append_field(bundle, "Docstring", "docstring", formatter)
             if detail_level > 0 and info["source"]:
                 append_field(bundle, "Source", "source", code_formatter)
             else:
                 append_field(bundle, "Init docstring", "init_docstring", formatter)
 
             append_field(bundle, "File", "file")
             append_field(bundle, "Type", "type_name")
             append_field(bundle, "Subclasses", "subclasses")
 
         else:
             # General Python objects
             append_field(bundle, "Signature", "definition", code_formatter)
             append_field(bundle, "Call signature", "call_def", code_formatter)
             append_field(bundle, "Type", "type_name")
             append_field(bundle, "String form", "string_form")
 
             # Namespace
             if info["namespace"] != "Interactive":
                 append_field(bundle, "Namespace", "namespace")
 
             append_field(bundle, "Length", "length")
             append_field(bundle, "File", "file")
 
             # Source or docstring, depending on detail level and whether
             # source found.
             if detail_level > 0 and info["source"]:
                 append_field(bundle, "Source", "source", code_formatter)
             else:
                 append_field(bundle, "Docstring", "docstring", formatter)
 
             append_field(bundle, "Class docstring", "class_docstring", formatter)
             append_field(bundle, "Init docstring", "init_docstring", formatter)
             append_field(bundle, "Call docstring", "call_docstring", formatter)
         return bundle
 
 
     def _get_info(
         self, obj, oname="", formatter=None, info=None, detail_level=0, omit_sections=()
     ):
         """Retrieve an info dict and format it.
 
         Parameters
         ----------
         obj : any
             Object to inspect and return info from
         oname : str (default: ''):
             Name of the variable pointing to `obj`.
         formatter : callable
         info
             already computed information
         detail_level : integer
             Granularity of detail level, if set to 1, give more information.
         omit_sections : container[str]
             Titles or keys to omit from output (can be set, tuple, etc., anything supporting `in`)
         """
 
         info = self.info(obj, oname=oname, info=info, detail_level=detail_level)
         bundle = self._make_info_unformatted(
             obj, info, formatter, detail_level=detail_level, omit_sections=omit_sections
         )
         return self.format_mime(bundle)
 
     def pinfo(
         self,
         obj,
         oname="",
         formatter=None,
         info=None,
         detail_level=0,
         enable_html_pager=True,
         omit_sections=(),
     ):
         """Show detailed information about an object.
 
         Optional arguments:
 
         - oname: name of the variable pointing to the object.
 
         - formatter: callable (optional)
               A special formatter for docstrings.
 
               The formatter is a callable that takes a string as an input
               and returns either a formatted string or a mime type bundle
               in the form of a dictionary.
 
               Although the support of custom formatter returning a string
               instead of a mime type bundle is deprecated.
 
         - info: a structure with some information fields which may have been
           precomputed already.
 
         - detail_level: if set to 1, more information is given.
 
         - omit_sections: set of section keys and titles to omit
         """
         info = self._get_info(
             obj, oname, formatter, info, detail_level, omit_sections=omit_sections
         )
         if not enable_html_pager:
             del info['text/html']
         page.page(info)
 
     def _info(self, obj, oname="", info=None, detail_level=0):
         """
         Inspector.info() was likely improperly marked as deprecated
         while only a parameter was deprecated. We "un-deprecate" it.
         """
 
         warnings.warn(
             "The `Inspector.info()` method has been un-deprecated as of 8.0 "
             "and the `formatter=` keyword removed. `Inspector._info` is now "
             "an alias, and you can just call `.info()` directly.",
             DeprecationWarning,
             stacklevel=2,
         )
         return self.info(obj, oname=oname, info=info, detail_level=detail_level)
 
     def info(self, obj, oname="", info=None, detail_level=0) -> dict:
         """Compute a dict with detailed information about an object.
 
         Parameters
         ----------
         obj : any
             An object to find information about
         oname : str (default: '')
             Name of the variable pointing to `obj`.
         info : (default: None)
             A struct (dict like with attr access) with some information fields
             which may have been precomputed already.
         detail_level : int (default:0)
             If set to 1, more information is given.
 
         Returns
         -------
         An object info dict with known fields from `info_fields`. Keys are
         strings, values are string or None.
         """
 
         if info is None:
             ismagic = False
             isalias = False
             ospace = ''
         else:
             ismagic = info.ismagic
             isalias = info.isalias
             ospace = info.namespace
 
         # Get docstring, special-casing aliases:
         if isalias:
             if not callable(obj):
                 try:
                     ds = "Alias to the system command:\n  %s" % obj[1]
                 except:
                     ds = "Alias: " + str(obj)
             else:
                 ds = "Alias to " + str(obj)
                 if obj.__doc__:
                     ds += "\nDocstring:\n" + obj.__doc__
         else:
-            ds = getdoc(obj)
-            if ds is None:
+            ds_or_None = getdoc(obj)
+            if ds_or_None is None:
                 ds = '<no docstring>'
+            else:
+                ds = ds_or_None
 
         # store output in a dict, we initialize it here and fill it as we go
         out = dict(name=oname, found=True, isalias=isalias, ismagic=ismagic, subclasses=None)
 
         string_max = 200 # max size of strings to show (snipped if longer)
         shalf = int((string_max - 5) / 2)
 
         if ismagic:
             out['type_name'] = 'Magic function'
         elif isalias:
             out['type_name'] = 'System alias'
         else:
             out['type_name'] = type(obj).__name__
 
         try:
             bclass = obj.__class__
             out['base_class'] = str(bclass)
         except:
             pass
 
         # String form, but snip if too long in ? form (full in ??)
         if detail_level >= self.str_detail_level:
             try:
                 ostr = str(obj)
                 str_head = 'string_form'
                 if not detail_level and len(ostr)>string_max:
                     ostr = ostr[:shalf] + ' <...> ' + ostr[-shalf:]
                     ostr = ("\n" + " " * len(str_head.expandtabs())).\
                             join(q.strip() for q in ostr.split("\n"))
                 out[str_head] = ostr
             except:
                 pass
 
         if ospace:
             out['namespace'] = ospace
 
         # Length (for strings and lists)
         try:
             out['length'] = str(len(obj))
         except Exception:
             pass
 
         # Filename where object was defined
         binary_file = False
         fname = find_file(obj)
         if fname is None:
             # if anything goes wrong, we don't want to show source, so it's as
             # if the file was binary
             binary_file = True
         else:
             if fname.endswith(('.so', '.dll', '.pyd')):
                 binary_file = True
             elif fname.endswith('<string>'):
                 fname = 'Dynamically generated function. No source code available.'
             out['file'] = compress_user(fname)
 
         # Original source code for a callable, class or property.
         if detail_level:
             # Flush the source cache because inspect can return out-of-date
             # source
             linecache.checkcache()
             try:
                 if isinstance(obj, property) or not binary_file:
                     src = getsource(obj, oname)
                     if src is not None:
                         src = src.rstrip()
                     out['source'] = src
 
             except Exception:
                 pass
 
         # Add docstring only if no source is to be shown (avoid repetitions).
         if ds and not self._source_contains_docstring(out.get('source'), ds):
             out['docstring'] = ds
 
         # Constructor docstring for classes
         if inspect.isclass(obj):
             out['isclass'] = True
 
             # get the init signature:
             try:
                 init_def = self._getdef(obj, oname)
             except AttributeError:
                 init_def = None
 
             # get the __init__ docstring
             try:
                 obj_init = obj.__init__
             except AttributeError:
                 init_ds = None
             else:
                 if init_def is None:
                     # Get signature from init if top-level sig failed.
                     # Can happen for built-in types (list, etc.).
                     try:
                         init_def = self._getdef(obj_init, oname)
                     except AttributeError:
                         pass
                 init_ds = getdoc(obj_init)
                 # Skip Python's auto-generated docstrings
                 if init_ds == _object_init_docstring:
                     init_ds = None
 
             if init_def:
                 out['init_definition'] = init_def
 
             if init_ds:
                 out['init_docstring'] = init_ds
 
             names = [sub.__name__ for sub in type.__subclasses__(obj)]
             if len(names) < 10:
                 all_names = ', '.join(names)
             else:
                 all_names = ', '.join(names[:10]+['...'])
             out['subclasses'] = all_names
         # and class docstring for instances:
         else:
             # reconstruct the function definition and print it:
             defln = self._getdef(obj, oname)
             if defln:
                 out['definition'] = defln
 
             # First, check whether the instance docstring is identical to the
             # class one, and print it separately if they don't coincide.  In
             # most cases they will, but it's nice to print all the info for
             # objects which use instance-customized docstrings.
             if ds:
                 try:
                     cls = getattr(obj,'__class__')
                 except:
                     class_ds = None
                 else:
                     class_ds = getdoc(cls)
                 # Skip Python's auto-generated docstrings
                 if class_ds in _builtin_type_docstrings:
                     class_ds = None
                 if class_ds and ds != class_ds:
                     out['class_docstring'] = class_ds
 
             # Next, try to show constructor docstrings
             try:
                 init_ds = getdoc(obj.__init__)
                 # Skip Python's auto-generated docstrings
                 if init_ds == _object_init_docstring:
                     init_ds = None
             except AttributeError:
                 init_ds = None
             if init_ds:
                 out['init_docstring'] = init_ds
 
             # Call form docstring for callable instances
             if safe_hasattr(obj, '__call__') and not is_simple_callable(obj):
                 call_def = self._getdef(obj.__call__, oname)
                 if call_def and (call_def != out.get('definition')):
                     # it may never be the case that call def and definition differ,
                     # but don't include the same signature twice
                     out['call_def'] = call_def
                 call_ds = getdoc(obj.__call__)
                 # Skip Python's auto-generated docstrings
                 if call_ds == _func_call_docstring:
                     call_ds = None
                 if call_ds:
                     out['call_docstring'] = call_ds
 
         return object_info(**out)
 
     @staticmethod
     def _source_contains_docstring(src, doc):
         """
         Check whether the source *src* contains the docstring *doc*.
 
         This is is helper function to skip displaying the docstring if the
         source already contains it, avoiding repetition of information.
         """
         try:
             def_node, = ast.parse(dedent(src)).body
             return ast.get_docstring(def_node) == doc
         except Exception:
             # The source can become invalid or even non-existent (because it
             # is re-fetched from the source file) so the above code fail in
             # arbitrary ways.
             return False
 
     def psearch(self,pattern,ns_table,ns_search=[],
                 ignore_case=False,show_all=False, *, list_types=False):
         """Search namespaces with wildcards for objects.
 
         Arguments:
 
         - pattern: string containing shell-like wildcards to use in namespace
           searches and optionally a type specification to narrow the search to
           objects of that type.
 
         - ns_table: dict of name->namespaces for search.
 
         Optional arguments:
 
           - ns_search: list of namespace names to include in search.
 
           - ignore_case(False): make the search case-insensitive.
 
           - show_all(False): show all names, including those starting with
             underscores.
 
           - list_types(False): list all available object types for object matching.
         """
         #print 'ps pattern:<%r>' % pattern # dbg
 
         # defaults
         type_pattern = 'all'
         filter = ''
 
         # list all object types
         if list_types:
             page.page('\n'.join(sorted(typestr2type)))
             return
 
         cmds = pattern.split()
         len_cmds  =  len(cmds)
         if len_cmds == 1:
             # Only filter pattern given
             filter = cmds[0]
         elif len_cmds == 2:
             # Both filter and type specified
             filter,type_pattern = cmds
         else:
             raise ValueError('invalid argument string for psearch: <%s>' %
                              pattern)
 
         # filter search namespaces
         for name in ns_search:
             if name not in ns_table:
                 raise ValueError('invalid namespace <%s>. Valid names: %s' %
                                  (name,ns_table.keys()))
 
         #print 'type_pattern:',type_pattern # dbg
         search_result, namespaces_seen = set(), set()
         for ns_name in ns_search:
             ns = ns_table[ns_name]
             # Normally, locals and globals are the same, so we just check one.
             if id(ns) in namespaces_seen:
                 continue
             namespaces_seen.add(id(ns))
             tmp_res = list_namespace(ns, type_pattern, filter,
                                     ignore_case=ignore_case, show_all=show_all)
             search_result.update(tmp_res)
 
         page.page('\n'.join(sorted(search_result)))
 
 
 def _render_signature(obj_signature, obj_name) -> str:
     """
     This was mostly taken from inspect.Signature.__str__.
     Look there for the comments.
     The only change is to add linebreaks when this gets too long.
     """
     result = []
     pos_only = False
     kw_only = True
     for param in obj_signature.parameters.values():
-        if param.kind == inspect._POSITIONAL_ONLY:
+        if param.kind == inspect.Parameter.POSITIONAL_ONLY:
             pos_only = True
         elif pos_only:
             result.append('/')
             pos_only = False
 
-        if param.kind == inspect._VAR_POSITIONAL:
+        if param.kind == inspect.Parameter.VAR_POSITIONAL:
             kw_only = False
-        elif param.kind == inspect._KEYWORD_ONLY and kw_only:
+        elif param.kind == inspect.Parameter.KEYWORD_ONLY and kw_only:
             result.append('*')
             kw_only = False
 
         result.append(str(param))
 
     if pos_only:
         result.append('/')
 
     # add up name, parameters, braces (2), and commas
     if len(obj_name) + sum(len(r) + 2 for r in result) > 75:
         # This doesn’t fit behind “Signature: ” in an inspect window.
         rendered = '{}(\n{})'.format(obj_name, ''.join(
             '    {},\n'.format(r) for r in result)
         )
     else:
         rendered = '{}({})'.format(obj_name, ', '.join(result))
 
     if obj_signature.return_annotation is not inspect._empty:
         anno = inspect.formatannotation(obj_signature.return_annotation)
         rendered += ' -> {}'.format(anno)
 
     return rendered

IPython/core/tests/test_interactiveshell.py

@@ -1,1200 +1,1200 b''
 # -*- coding: utf-8 -*-
 """Tests for the key interactiveshell module.
 
 Historically the main classes in interactiveshell have been under-tested.  This
 module should grow as many single-method tests as possible to trap many of the
 recurring bugs we seem to encounter with high-level interaction.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import asyncio
 import ast
 import os
 import signal
 import shutil
 import sys
 import tempfile
 import unittest
 import pytest
 from unittest import mock
 
 from os.path import join
 
 from IPython.core.error import InputRejected
 from IPython.core.inputtransformer import InputTransformer
 from IPython.core import interactiveshell
 from IPython.core.oinspect import OInfo
 from IPython.testing.decorators import (
     skipif, skip_win32, onlyif_unicode_paths, onlyif_cmds_exist,
 )
 from IPython.testing import tools as tt
 from IPython.utils.process import find_cmd
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 # This is used by every single test, no point repeating it ad nauseam
 
 #-----------------------------------------------------------------------------
 # Tests
 #-----------------------------------------------------------------------------
 
 class DerivedInterrupt(KeyboardInterrupt):
     pass
 
 class InteractiveShellTestCase(unittest.TestCase):
     def test_naked_string_cells(self):
         """Test that cells with only naked strings are fully executed"""
         # First, single-line inputs
         ip.run_cell('"a"\n')
         self.assertEqual(ip.user_ns['_'], 'a')
         # And also multi-line cells
         ip.run_cell('"""a\nb"""\n')
         self.assertEqual(ip.user_ns['_'], 'a\nb')
 
     def test_run_empty_cell(self):
         """Just make sure we don't get a horrible error with a blank
         cell of input. Yes, I did overlook that."""
         old_xc = ip.execution_count
         res = ip.run_cell('')
         self.assertEqual(ip.execution_count, old_xc)
         self.assertEqual(res.execution_count, None)
 
     def test_run_cell_multiline(self):
         """Multi-block, multi-line cells must execute correctly.
         """
         src = '\n'.join(["x=1",
                          "y=2",
                          "if 1:",
                          "    x += 1",
                          "    y += 1",])
         res = ip.run_cell(src)
         self.assertEqual(ip.user_ns['x'], 2)
         self.assertEqual(ip.user_ns['y'], 3)
         self.assertEqual(res.success, True)
         self.assertEqual(res.result, None)
 
     def test_multiline_string_cells(self):
         "Code sprinkled with multiline strings should execute (GH-306)"
         ip.run_cell('tmp=0')
         self.assertEqual(ip.user_ns['tmp'], 0)
         res = ip.run_cell('tmp=1;"""a\nb"""\n')
         self.assertEqual(ip.user_ns['tmp'], 1)
         self.assertEqual(res.success, True)
         self.assertEqual(res.result, "a\nb")
 
     def test_dont_cache_with_semicolon(self):
         "Ending a line with semicolon should not cache the returned object (GH-307)"
         oldlen = len(ip.user_ns['Out'])
         for cell in ['1;', '1;1;']:
             res = ip.run_cell(cell, store_history=True)
             newlen = len(ip.user_ns['Out'])
             self.assertEqual(oldlen, newlen)
             self.assertIsNone(res.result)
         i = 0
         #also test the default caching behavior
         for cell in ['1', '1;1']:
             ip.run_cell(cell, store_history=True)
             newlen = len(ip.user_ns['Out'])
             i += 1
             self.assertEqual(oldlen+i, newlen)
 
     def test_syntax_error(self):
         res = ip.run_cell("raise = 3")
         self.assertIsInstance(res.error_before_exec, SyntaxError)
 
     def test_open_standard_input_stream(self):
         res = ip.run_cell("open(0)")
         self.assertIsInstance(res.error_in_exec, ValueError)
 
     def test_open_standard_output_stream(self):
         res = ip.run_cell("open(1)")
         self.assertIsInstance(res.error_in_exec, ValueError)
 
     def test_open_standard_error_stream(self):
         res = ip.run_cell("open(2)")
         self.assertIsInstance(res.error_in_exec, ValueError)
 
     def test_In_variable(self):
         "Verify that In variable grows with user input (GH-284)"
         oldlen = len(ip.user_ns['In'])
         ip.run_cell('1;', store_history=True)
         newlen = len(ip.user_ns['In'])
         self.assertEqual(oldlen+1, newlen)
         self.assertEqual(ip.user_ns['In'][-1],'1;')
         
     def test_magic_names_in_string(self):
         ip.run_cell('a = """\n%exit\n"""')
         self.assertEqual(ip.user_ns['a'], '\n%exit\n')
     
     def test_trailing_newline(self):
         """test that running !(command) does not raise a SyntaxError"""
         ip.run_cell('!(true)\n', False)
         ip.run_cell('!(true)\n\n\n', False)
     
     def test_gh_597(self):
         """Pretty-printing lists of objects with non-ascii reprs may cause
         problems."""
         class Spam(object):
             def __repr__(self):
                 return "\xe9"*50
         import IPython.core.formatters
         f = IPython.core.formatters.PlainTextFormatter()
         f([Spam(),Spam()])
     
 
     def test_future_flags(self):
         """Check that future flags are used for parsing code (gh-777)"""
         ip.run_cell('from __future__ import barry_as_FLUFL')
         try:
             ip.run_cell('prfunc_return_val = 1 <> 2')
             assert 'prfunc_return_val' in ip.user_ns
         finally:
             # Reset compiler flags so we don't mess up other tests.
             ip.compile.reset_compiler_flags()
 
     def test_can_pickle(self):
         "Can we pickle objects defined interactively (GH-29)"
         ip = get_ipython()
         ip.reset()
         ip.run_cell(("class Mylist(list):\n"
                      "    def __init__(self,x=[]):\n"
                      "        list.__init__(self,x)"))
         ip.run_cell("w=Mylist([1,2,3])")
         
         from pickle import dumps
         
         # We need to swap in our main module - this is only necessary
         # inside the test framework, because IPython puts the interactive module
         # in place (but the test framework undoes this).
         _main = sys.modules['__main__']
         sys.modules['__main__'] = ip.user_module
         try:
             res = dumps(ip.user_ns["w"])
         finally:
             sys.modules['__main__'] = _main
         self.assertTrue(isinstance(res, bytes))
         
     def test_global_ns(self):
         "Code in functions must be able to access variables outside them."
         ip = get_ipython()
         ip.run_cell("a = 10")
         ip.run_cell(("def f(x):\n"
                      "    return x + a"))
         ip.run_cell("b = f(12)")
         self.assertEqual(ip.user_ns["b"], 22)
 
     def test_bad_custom_tb(self):
         """Check that InteractiveShell is protected from bad custom exception handlers"""
         ip.set_custom_exc((IOError,), lambda etype,value,tb: 1/0)
         self.assertEqual(ip.custom_exceptions, (IOError,))
         with tt.AssertPrints("Custom TB Handler failed", channel='stderr'):
             ip.run_cell(u'raise IOError("foo")')
         self.assertEqual(ip.custom_exceptions, ())
 
     def test_bad_custom_tb_return(self):
         """Check that InteractiveShell is protected from bad return types in custom exception handlers"""
         ip.set_custom_exc((NameError,),lambda etype,value,tb, tb_offset=None: 1)
         self.assertEqual(ip.custom_exceptions, (NameError,))
         with tt.AssertPrints("Custom TB Handler failed", channel='stderr'):
             ip.run_cell(u'a=abracadabra')
         self.assertEqual(ip.custom_exceptions, ())
 
     def test_drop_by_id(self):
         myvars = {"a":object(), "b":object(), "c": object()}
         ip.push(myvars, interactive=False)
         for name in myvars:
             assert name in ip.user_ns, name
             assert name in ip.user_ns_hidden, name
         ip.user_ns['b'] = 12
         ip.drop_by_id(myvars)
         for name in ["a", "c"]:
             assert name not in ip.user_ns, name
             assert name not in ip.user_ns_hidden, name
         assert ip.user_ns['b'] == 12
         ip.reset()
 
     def test_var_expand(self):
         ip.user_ns['f'] = u'Ca\xf1o'
         self.assertEqual(ip.var_expand(u'echo $f'), u'echo Ca\xf1o')
         self.assertEqual(ip.var_expand(u'echo {f}'), u'echo Ca\xf1o')
         self.assertEqual(ip.var_expand(u'echo {f[:-1]}'), u'echo Ca\xf1')
         self.assertEqual(ip.var_expand(u'echo {1*2}'), u'echo 2')
         
         self.assertEqual(ip.var_expand(u"grep x | awk '{print $1}'"), u"grep x | awk '{print $1}'")
 
         ip.user_ns['f'] = b'Ca\xc3\xb1o'
         # This should not raise any exception:
         ip.var_expand(u'echo $f')
    
     def test_var_expand_local(self):
         """Test local variable expansion in !system and %magic calls"""
         # !system
         ip.run_cell(
             "def test():\n"
             '    lvar = "ttt"\n'
             "    ret = !echo {lvar}\n"
             "    return ret[0]\n"
         )
         res = ip.user_ns["test"]()
         self.assertIn("ttt", res)
 
         # %magic
         ip.run_cell(
             "def makemacro():\n"
             '    macroname = "macro_var_expand_locals"\n'
             "    %macro {macroname} codestr\n"
         )
         ip.user_ns["codestr"] = "str(12)"
         ip.run_cell("makemacro()")
         self.assertIn("macro_var_expand_locals", ip.user_ns)
 
     def test_var_expand_self(self):
         """Test variable expansion with the name 'self', which was failing.
         
         See https://github.com/ipython/ipython/issues/1878#issuecomment-7698218
         """
         ip.run_cell(
             "class cTest:\n"
             '  classvar="see me"\n'
             "  def test(self):\n"
             "    res = !echo Variable: {self.classvar}\n"
             "    return res[0]\n"
         )
         self.assertIn("see me", ip.user_ns["cTest"]().test())
 
     def test_bad_var_expand(self):
         """var_expand on invalid formats shouldn't raise"""
         # SyntaxError
         self.assertEqual(ip.var_expand(u"{'a':5}"), u"{'a':5}")
         # NameError
         self.assertEqual(ip.var_expand(u"{asdf}"), u"{asdf}")
         # ZeroDivisionError
         self.assertEqual(ip.var_expand(u"{1/0}"), u"{1/0}")
     
     def test_silent_postexec(self):
         """run_cell(silent=True) doesn't invoke pre/post_run_cell callbacks"""
         pre_explicit = mock.Mock()
         pre_always = mock.Mock()
         post_explicit = mock.Mock()
         post_always = mock.Mock()
         all_mocks = [pre_explicit, pre_always, post_explicit, post_always]
         
         ip.events.register('pre_run_cell', pre_explicit)
         ip.events.register('pre_execute', pre_always)
         ip.events.register('post_run_cell', post_explicit)
         ip.events.register('post_execute', post_always)
         
         try:
             ip.run_cell("1", silent=True)
             assert pre_always.called
             assert not pre_explicit.called
             assert post_always.called
             assert not post_explicit.called
             # double-check that non-silent exec did what we expected
             # silent to avoid
             ip.run_cell("1")
             assert pre_explicit.called
             assert post_explicit.called
             info, = pre_explicit.call_args[0]
             result, = post_explicit.call_args[0]
             self.assertEqual(info, result.info)
             # check that post hooks are always called
             [m.reset_mock() for m in all_mocks]
             ip.run_cell("syntax error")
             assert pre_always.called
             assert pre_explicit.called
             assert post_always.called
             assert post_explicit.called
             info, = pre_explicit.call_args[0]
             result, = post_explicit.call_args[0]
             self.assertEqual(info, result.info)
         finally:
             # remove post-exec
             ip.events.unregister('pre_run_cell', pre_explicit)
             ip.events.unregister('pre_execute', pre_always)
             ip.events.unregister('post_run_cell', post_explicit)
             ip.events.unregister('post_execute', post_always)
     
     def test_silent_noadvance(self):
         """run_cell(silent=True) doesn't advance execution_count"""
         ec = ip.execution_count
         # silent should force store_history=False
         ip.run_cell("1", store_history=True, silent=True)
         
         self.assertEqual(ec, ip.execution_count)
         # double-check that non-silent exec did what we expected
         # silent to avoid
         ip.run_cell("1", store_history=True)
         self.assertEqual(ec+1, ip.execution_count)
     
     def test_silent_nodisplayhook(self):
         """run_cell(silent=True) doesn't trigger displayhook"""
         d = dict(called=False)
         
         trap = ip.display_trap
         save_hook = trap.hook
         
         def failing_hook(*args, **kwargs):
             d['called'] = True
         
         try:
             trap.hook = failing_hook
             res = ip.run_cell("1", silent=True)
             self.assertFalse(d['called'])
             self.assertIsNone(res.result)
             # double-check that non-silent exec did what we expected
             # silent to avoid
             ip.run_cell("1")
             self.assertTrue(d['called'])
         finally:
             trap.hook = save_hook
 
     def test_ofind_line_magic(self):
         from IPython.core.magic import register_line_magic
         
         @register_line_magic
         def lmagic(line):
             "A line magic"
 
         # Get info on line magic
         lfind = ip._ofind("lmagic")
         info = OInfo(
             found=True,
             isalias=False,
             ismagic=True,
             namespace="IPython internal",
             obj=lmagic,
             parent=None,
         )
         self.assertEqual(lfind, info)
         
     def test_ofind_cell_magic(self):
         from IPython.core.magic import register_cell_magic
         
         @register_cell_magic
         def cmagic(line, cell):
             "A cell magic"
 
         # Get info on cell magic
         find = ip._ofind("cmagic")
         info = OInfo(
             found=True,
             isalias=False,
             ismagic=True,
             namespace="IPython internal",
             obj=cmagic,
             parent=None,
         )
         self.assertEqual(find, info)
 
     def test_ofind_property_with_error(self):
         class A(object):
             @property
             def foo(self):
                 raise NotImplementedError()  # pragma: no cover
 
         a = A()
 
         found = ip._ofind("a.foo", [("locals", locals())])
         info = OInfo(
             found=True,
             isalias=False,
             ismagic=False,
             namespace="locals",
             obj=A.foo,
             parent=a,
         )
         self.assertEqual(found, info)
 
     def test_ofind_multiple_attribute_lookups(self):
         class A(object):
             @property
             def foo(self):
                 raise NotImplementedError()  # pragma: no cover
 
         a = A()
         a.a = A()
         a.a.a = A()
 
         found = ip._ofind("a.a.a.foo", [("locals", locals())])
         info = OInfo(
             found=True,
             isalias=False,
             ismagic=False,
             namespace="locals",
             obj=A.foo,
             parent=a.a.a,
         )
         self.assertEqual(found, info)
 
     def test_ofind_slotted_attributes(self):
         class A(object):
             __slots__ = ['foo']
             def __init__(self):
                 self.foo = 'bar'
 
         a = A()
         found = ip._ofind("a.foo", [("locals", locals())])
         info = OInfo(
             found=True,
             isalias=False,
             ismagic=False,
             namespace="locals",
             obj=a.foo,
             parent=a,
         )
         self.assertEqual(found, info)
 
         found = ip._ofind("a.bar", [("locals", locals())])
-        info = OInfo(
+        expected = OInfo(
             found=False,
             isalias=False,
             ismagic=False,
             namespace=None,
             obj=None,
             parent=a,
         )
-        self.assertEqual(found, info)
+        assert found == expected
 
     def test_ofind_prefers_property_to_instance_level_attribute(self):
         class A(object):
             @property
             def foo(self):
                 return 'bar'
         a = A()
         a.__dict__["foo"] = "baz"
         self.assertEqual(a.foo, "bar")
         found = ip._ofind("a.foo", [("locals", locals())])
         self.assertIs(found.obj, A.foo)
 
     def test_custom_syntaxerror_exception(self):
         called = []
         def my_handler(shell, etype, value, tb, tb_offset=None):
             called.append(etype)
             shell.showtraceback((etype, value, tb), tb_offset=tb_offset)
 
         ip.set_custom_exc((SyntaxError,), my_handler)
         try:
             ip.run_cell("1f")
             # Check that this was called, and only once.
             self.assertEqual(called, [SyntaxError])
         finally:
             # Reset the custom exception hook
             ip.set_custom_exc((), None)
 
     def test_custom_exception(self):
         called = []
         def my_handler(shell, etype, value, tb, tb_offset=None):
             called.append(etype)
             shell.showtraceback((etype, value, tb), tb_offset=tb_offset)
         
         ip.set_custom_exc((ValueError,), my_handler)
         try:
             res = ip.run_cell("raise ValueError('test')")
             # Check that this was called, and only once.
             self.assertEqual(called, [ValueError])
             # Check that the error is on the result object
             self.assertIsInstance(res.error_in_exec, ValueError)
         finally:
             # Reset the custom exception hook
             ip.set_custom_exc((), None)
     
     @mock.patch("builtins.print")
     def test_showtraceback_with_surrogates(self, mocked_print):
         values = []
 
         def mock_print_func(value, sep=" ", end="\n", file=sys.stdout, flush=False):
             values.append(value)
             if value == chr(0xD8FF):
                 raise UnicodeEncodeError("utf-8", chr(0xD8FF), 0, 1, "")
 
         # mock builtins.print
         mocked_print.side_effect = mock_print_func
 
         # ip._showtraceback() is replaced in globalipapp.py.
         # Call original method to test.
         interactiveshell.InteractiveShell._showtraceback(ip, None, None, chr(0xD8FF))
 
         self.assertEqual(mocked_print.call_count, 2)
         self.assertEqual(values, [chr(0xD8FF), "\\ud8ff"])
 
     def test_mktempfile(self):
         filename = ip.mktempfile()
         # Check that we can open the file again on Windows
         with open(filename, "w", encoding="utf-8") as f:
             f.write("abc")
 
         filename = ip.mktempfile(data="blah")
         with open(filename, "r", encoding="utf-8") as f:
             self.assertEqual(f.read(), "blah")
 
     def test_new_main_mod(self):
         # Smoketest to check that this accepts a unicode module name
         name = u'jiefmw'
         mod = ip.new_main_mod(u'%s.py' % name, name)
         self.assertEqual(mod.__name__, name)
 
     def test_get_exception_only(self):
         try:
             raise KeyboardInterrupt
         except KeyboardInterrupt:
             msg = ip.get_exception_only()
         self.assertEqual(msg, 'KeyboardInterrupt\n')
 
         try:
             raise DerivedInterrupt("foo")
         except KeyboardInterrupt:
             msg = ip.get_exception_only()
         self.assertEqual(msg, 'IPython.core.tests.test_interactiveshell.DerivedInterrupt: foo\n')
 
     def test_inspect_text(self):
         ip.run_cell('a = 5')
         text = ip.object_inspect_text('a')
         self.assertIsInstance(text, str)
 
     def test_last_execution_result(self):
         """ Check that last execution result gets set correctly (GH-10702) """
         result = ip.run_cell('a = 5; a')
         self.assertTrue(ip.last_execution_succeeded)
         self.assertEqual(ip.last_execution_result.result, 5)
 
         result = ip.run_cell('a = x_invalid_id_x')
         self.assertFalse(ip.last_execution_succeeded)
         self.assertFalse(ip.last_execution_result.success)
         self.assertIsInstance(ip.last_execution_result.error_in_exec, NameError)
 
     def test_reset_aliasing(self):
         """ Check that standard posix aliases work after %reset. """
         if os.name != 'posix':
             return
 
         ip.reset()
         for cmd in ('clear', 'more', 'less', 'man'):
             res = ip.run_cell('%' + cmd)
             self.assertEqual(res.success, True)
 
 
 class TestSafeExecfileNonAsciiPath(unittest.TestCase):
 
     @onlyif_unicode_paths
     def setUp(self):
         self.BASETESTDIR = tempfile.mkdtemp()
         self.TESTDIR = join(self.BASETESTDIR, u"åäö")
         os.mkdir(self.TESTDIR)
         with open(
             join(self.TESTDIR, "åäötestscript.py"), "w", encoding="utf-8"
         ) as sfile:
             sfile.write("pass\n")
         self.oldpath = os.getcwd()
         os.chdir(self.TESTDIR)
         self.fname = u"åäötestscript.py"
 
     def tearDown(self):
         os.chdir(self.oldpath)
         shutil.rmtree(self.BASETESTDIR)
 
     @onlyif_unicode_paths
     def test_1(self):
         """Test safe_execfile with non-ascii path
         """
         ip.safe_execfile(self.fname, {}, raise_exceptions=True)
 
 class ExitCodeChecks(tt.TempFileMixin):
 
     def setUp(self):
         self.system = ip.system_raw
 
     def test_exit_code_ok(self):
         self.system('exit 0')
         self.assertEqual(ip.user_ns['_exit_code'], 0)
 
     def test_exit_code_error(self):
         self.system('exit 1')
         self.assertEqual(ip.user_ns['_exit_code'], 1)
     
     @skipif(not hasattr(signal, 'SIGALRM'))
     def test_exit_code_signal(self):
         self.mktmp("import signal, time\n"
                    "signal.setitimer(signal.ITIMER_REAL, 0.1)\n"
                    "time.sleep(1)\n")
         self.system("%s %s" % (sys.executable, self.fname))
         self.assertEqual(ip.user_ns['_exit_code'], -signal.SIGALRM)
     
     @onlyif_cmds_exist("csh")
     def test_exit_code_signal_csh(self):  # pragma: no cover
         SHELL = os.environ.get("SHELL", None)
         os.environ["SHELL"] = find_cmd("csh")
         try:
             self.test_exit_code_signal()
         finally:
             if SHELL is not None:
                 os.environ['SHELL'] = SHELL
             else:
                 del os.environ['SHELL']
 
 
 class TestSystemRaw(ExitCodeChecks):
 
     def setUp(self):
         super().setUp()
         self.system = ip.system_raw
 
     @onlyif_unicode_paths
     def test_1(self):
         """Test system_raw with non-ascii cmd
         """
         cmd = u'''python -c "'åäö'"   '''
         ip.system_raw(cmd)
 
     @mock.patch('subprocess.call', side_effect=KeyboardInterrupt)
     @mock.patch('os.system', side_effect=KeyboardInterrupt)
     def test_control_c(self, *mocks):
         try:
             self.system("sleep 1 # wont happen")
         except KeyboardInterrupt:  # pragma: no cove
             self.fail(
                 "system call should intercept "
                 "keyboard interrupt from subprocess.call"
             )
         self.assertEqual(ip.user_ns["_exit_code"], -signal.SIGINT)
 
 
 @pytest.mark.parametrize("magic_cmd", ["pip", "conda", "cd"])
 def test_magic_warnings(magic_cmd):
     if sys.platform == "win32":
         to_mock = "os.system"
         expected_arg, expected_kwargs = magic_cmd, dict()
     else:
         to_mock = "subprocess.call"
         expected_arg, expected_kwargs = magic_cmd, dict(
             shell=True, executable=os.environ.get("SHELL", None)
         )
 
     with mock.patch(to_mock, return_value=0) as mock_sub:
         with pytest.warns(Warning, match=r"You executed the system command"):
             ip.system_raw(magic_cmd)
         mock_sub.assert_called_once_with(expected_arg, **expected_kwargs)
 
 
 # TODO: Exit codes are currently ignored on Windows.
 class TestSystemPipedExitCode(ExitCodeChecks):
 
     def setUp(self):
         super().setUp()
         self.system = ip.system_piped
 
     @skip_win32
     def test_exit_code_ok(self):
         ExitCodeChecks.test_exit_code_ok(self)
 
     @skip_win32
     def test_exit_code_error(self):
         ExitCodeChecks.test_exit_code_error(self)
 
     @skip_win32
     def test_exit_code_signal(self):
         ExitCodeChecks.test_exit_code_signal(self)
 
 class TestModules(tt.TempFileMixin):
     def test_extraneous_loads(self):
         """Test we're not loading modules on startup that we shouldn't.
         """
         self.mktmp("import sys\n"
                    "print('numpy' in sys.modules)\n"
                    "print('ipyparallel' in sys.modules)\n"
                    "print('ipykernel' in sys.modules)\n"
                    )
         out = "False\nFalse\nFalse\n"
         tt.ipexec_validate(self.fname, out)
 
 class Negator(ast.NodeTransformer):
     """Negates all number literals in an AST."""
 
     # for python 3.7 and earlier
     def visit_Num(self, node):
         node.n = -node.n
         return node
 
     # for python 3.8+
     def visit_Constant(self, node):
         if isinstance(node.value, int):
             return self.visit_Num(node)
         return node
 
 class TestAstTransform(unittest.TestCase):
     def setUp(self):
         self.negator = Negator()
         ip.ast_transformers.append(self.negator)
     
     def tearDown(self):
         ip.ast_transformers.remove(self.negator)
 
     def test_non_int_const(self):
         with tt.AssertPrints("hello"):
             ip.run_cell('print("hello")')
 
     def test_run_cell(self):
         with tt.AssertPrints("-34"):
             ip.run_cell("print(12 + 22)")
 
         # A named reference to a number shouldn't be transformed.
         ip.user_ns["n"] = 55
         with tt.AssertNotPrints("-55"):
             ip.run_cell("print(n)")
 
     def test_timeit(self):
         called = set()
         def f(x):
             called.add(x)
         ip.push({'f':f})
         
         with tt.AssertPrints("std. dev. of"):
             ip.run_line_magic("timeit", "-n1 f(1)")
         self.assertEqual(called, {-1})
         called.clear()
 
         with tt.AssertPrints("std. dev. of"):
             ip.run_cell_magic("timeit", "-n1 f(2)", "f(3)")
         self.assertEqual(called, {-2, -3})
     
     def test_time(self):
         called = []
         def f(x):
             called.append(x)
         ip.push({'f':f})
         
         # Test with an expression
         with tt.AssertPrints("Wall time: "):
             ip.run_line_magic("time", "f(5+9)")
         self.assertEqual(called, [-14])
         called[:] = []
         
         # Test with a statement (different code path)
         with tt.AssertPrints("Wall time: "):
             ip.run_line_magic("time", "a = f(-3 + -2)")
         self.assertEqual(called, [5])
     
     def test_macro(self):
         ip.push({'a':10})
         # The AST transformation makes this do a+=-1
         ip.define_macro("amacro", "a+=1\nprint(a)")
         
         with tt.AssertPrints("9"):
             ip.run_cell("amacro")
         with tt.AssertPrints("8"):
             ip.run_cell("amacro")
 
 class TestMiscTransform(unittest.TestCase):
 
 
     def test_transform_only_once(self):
         cleanup = 0
         line_t = 0
         def count_cleanup(lines):
             nonlocal cleanup
             cleanup += 1
             return lines
 
         def count_line_t(lines):
             nonlocal line_t
             line_t += 1
             return lines
 
         ip.input_transformer_manager.cleanup_transforms.append(count_cleanup)
         ip.input_transformer_manager.line_transforms.append(count_line_t)
 
         ip.run_cell('1')
 
         assert cleanup == 1
         assert line_t == 1
 
 class IntegerWrapper(ast.NodeTransformer):
     """Wraps all integers in a call to Integer()"""
 
     # for Python 3.7 and earlier
 
     # for Python 3.7 and earlier
     def visit_Num(self, node):
         if isinstance(node.n, int):
             return ast.Call(func=ast.Name(id='Integer', ctx=ast.Load()),
                             args=[node], keywords=[])
         return node
 
     # For Python 3.8+
     def visit_Constant(self, node):
         if isinstance(node.value, int):
             return self.visit_Num(node)
         return node
 
 
 class TestAstTransform2(unittest.TestCase):
     def setUp(self):
         self.intwrapper = IntegerWrapper()
         ip.ast_transformers.append(self.intwrapper)
         
         self.calls = []
         def Integer(*args):
             self.calls.append(args)
             return args
         ip.push({"Integer": Integer})
     
     def tearDown(self):
         ip.ast_transformers.remove(self.intwrapper)
         del ip.user_ns['Integer']
     
     def test_run_cell(self):
         ip.run_cell("n = 2")
         self.assertEqual(self.calls, [(2,)])
         
         # This shouldn't throw an error
         ip.run_cell("o = 2.0")
         self.assertEqual(ip.user_ns['o'], 2.0)
 
     def test_run_cell_non_int(self):
         ip.run_cell("n = 'a'")
         assert self.calls == []
 
     def test_timeit(self):
         called = set()
         def f(x):
             called.add(x)
         ip.push({'f':f})
 
         with tt.AssertPrints("std. dev. of"):
             ip.run_line_magic("timeit", "-n1 f(1)")
         self.assertEqual(called, {(1,)})
         called.clear()
 
         with tt.AssertPrints("std. dev. of"):
             ip.run_cell_magic("timeit", "-n1 f(2)", "f(3)")
         self.assertEqual(called, {(2,), (3,)})
 
 class ErrorTransformer(ast.NodeTransformer):
     """Throws an error when it sees a number."""
 
     def visit_Constant(self, node):
         if isinstance(node.value, int):
             raise ValueError("test")
         return node
 
 
 class TestAstTransformError(unittest.TestCase):
     def test_unregistering(self):
         err_transformer = ErrorTransformer()
         ip.ast_transformers.append(err_transformer)
         
         with self.assertWarnsRegex(UserWarning, "It will be unregistered"):
             ip.run_cell("1 + 2")
         
         # This should have been removed.
         self.assertNotIn(err_transformer, ip.ast_transformers)
 
 
 class StringRejector(ast.NodeTransformer):
     """Throws an InputRejected when it sees a string literal.
 
     Used to verify that NodeTransformers can signal that a piece of code should
     not be executed by throwing an InputRejected.
     """
     
     # 3.8 only
     def visit_Constant(self, node):
         if isinstance(node.value, str):
             raise InputRejected("test")
         return node
 
 
 class TestAstTransformInputRejection(unittest.TestCase):
 
     def setUp(self):
         self.transformer = StringRejector()
         ip.ast_transformers.append(self.transformer)
 
     def tearDown(self):
         ip.ast_transformers.remove(self.transformer)
 
     def test_input_rejection(self):
         """Check that NodeTransformers can reject input."""
 
         expect_exception_tb = tt.AssertPrints("InputRejected: test")
         expect_no_cell_output = tt.AssertNotPrints("'unsafe'", suppress=False)
 
         # Run the same check twice to verify that the transformer is not
         # disabled after raising.
         with expect_exception_tb, expect_no_cell_output:
             ip.run_cell("'unsafe'")
 
         with expect_exception_tb, expect_no_cell_output:
             res = ip.run_cell("'unsafe'")
 
         self.assertIsInstance(res.error_before_exec, InputRejected)
 
 def test__IPYTHON__():
     # This shouldn't raise a NameError, that's all
     __IPYTHON__
 
 
 class DummyRepr(object):
     def __repr__(self):
         return "DummyRepr"
     
     def _repr_html_(self):
         return "<b>dummy</b>"
     
     def _repr_javascript_(self):
         return "console.log('hi');", {'key': 'value'}
     
 
 def test_user_variables():
     # enable all formatters
     ip.display_formatter.active_types = ip.display_formatter.format_types
     
     ip.user_ns['dummy'] = d = DummyRepr()
     keys = {'dummy', 'doesnotexist'}
     r = ip.user_expressions({ key:key for key in keys})
 
     assert keys == set(r.keys())
     dummy = r["dummy"]
     assert {"status", "data", "metadata"} == set(dummy.keys())
     assert dummy["status"] == "ok"
     data = dummy["data"]
     metadata = dummy["metadata"]
     assert data.get("text/html") == d._repr_html_()
     js, jsmd = d._repr_javascript_()
     assert data.get("application/javascript") == js
     assert metadata.get("application/javascript") == jsmd
 
     dne = r["doesnotexist"]
     assert dne["status"] == "error"
     assert dne["ename"] == "NameError"
 
     # back to text only
     ip.display_formatter.active_types = ['text/plain']
     
 def test_user_expression():
     # enable all formatters
     ip.display_formatter.active_types = ip.display_formatter.format_types
     query = {
         'a' : '1 + 2',
         'b' : '1/0',
     }
     r = ip.user_expressions(query)
     import pprint
     pprint.pprint(r)
     assert set(r.keys()) == set(query.keys())
     a = r["a"]
     assert {"status", "data", "metadata"} == set(a.keys())
     assert a["status"] == "ok"
     data = a["data"]
     metadata = a["metadata"]
     assert data.get("text/plain") == "3"
 
     b = r["b"]
     assert b["status"] == "error"
     assert b["ename"] == "ZeroDivisionError"
 
     # back to text only
     ip.display_formatter.active_types = ['text/plain']
 
 
 class TestSyntaxErrorTransformer(unittest.TestCase):
     """Check that SyntaxError raised by an input transformer is handled by run_cell()"""
 
     @staticmethod
     def transformer(lines):
         for line in lines:
             pos = line.find('syntaxerror')
             if pos >= 0:
                 e = SyntaxError('input contains "syntaxerror"')
                 e.text = line
                 e.offset = pos + 1
                 raise e
         return lines
 
     def setUp(self):
         ip.input_transformers_post.append(self.transformer)
 
     def tearDown(self):
         ip.input_transformers_post.remove(self.transformer)
 
     def test_syntaxerror_input_transformer(self):
         with tt.AssertPrints('1234'):
             ip.run_cell('1234')
         with tt.AssertPrints('SyntaxError: invalid syntax'):
             ip.run_cell('1 2 3')   # plain python syntax error
         with tt.AssertPrints('SyntaxError: input contains "syntaxerror"'):
             ip.run_cell('2345  # syntaxerror')  # input transformer syntax error
         with tt.AssertPrints('3456'):
             ip.run_cell('3456')
 
 
 class TestWarningSuppression(unittest.TestCase):
     def test_warning_suppression(self):
         ip.run_cell("import warnings")
         try:
             with self.assertWarnsRegex(UserWarning, "asdf"):
                 ip.run_cell("warnings.warn('asdf')")
             # Here's the real test -- if we run that again, we should get the
             # warning again. Traditionally, each warning was only issued once per
             # IPython session (approximately), even if the user typed in new and
             # different code that should have also triggered the warning, leading
             # to much confusion.
             with self.assertWarnsRegex(UserWarning, "asdf"):
                 ip.run_cell("warnings.warn('asdf')")
         finally:
             ip.run_cell("del warnings")
 
 
     def test_deprecation_warning(self):
         ip.run_cell("""
 import warnings
 def wrn():
     warnings.warn(
         "I AM  A WARNING",
         DeprecationWarning
     )
         """)
         try:
             with self.assertWarnsRegex(DeprecationWarning, "I AM  A WARNING"):
                 ip.run_cell("wrn()")
         finally:
             ip.run_cell("del warnings")
             ip.run_cell("del wrn")
 
 
 class TestImportNoDeprecate(tt.TempFileMixin):
 
     def setUp(self):
         """Make a valid python temp file."""
         self.mktmp("""
 import warnings
 def wrn():
     warnings.warn(
         "I AM  A WARNING",
         DeprecationWarning
     )
 """)
         super().setUp()
 
     def test_no_dep(self):
         """
         No deprecation warning should be raised from imported functions
         """
         ip.run_cell("from {} import wrn".format(self.fname))
 
         with tt.AssertNotPrints("I AM  A WARNING"):
             ip.run_cell("wrn()")
         ip.run_cell("del wrn")
 
 
 def test_custom_exc_count():
     hook = mock.Mock(return_value=None)
     ip.set_custom_exc((SyntaxError,), hook)
     before = ip.execution_count
     ip.run_cell("def foo()", store_history=True)
     # restore default excepthook
     ip.set_custom_exc((), None)
     assert hook.call_count == 1
     assert ip.execution_count == before + 1
 
 
 def test_run_cell_async():
     ip.run_cell("import asyncio")
     coro = ip.run_cell_async("await asyncio.sleep(0.01)\n5")
     assert asyncio.iscoroutine(coro)
     loop = asyncio.new_event_loop()
     result = loop.run_until_complete(coro)
     assert isinstance(result, interactiveshell.ExecutionResult)
     assert result.result == 5
 
 
 def test_run_cell_await():
     ip.run_cell("import asyncio")
     result = ip.run_cell("await asyncio.sleep(0.01); 10")
     assert ip.user_ns["_"] == 10
 
 
 def test_run_cell_asyncio_run():
     ip.run_cell("import asyncio")
     result = ip.run_cell("await asyncio.sleep(0.01); 1")
     assert ip.user_ns["_"] == 1
     result = ip.run_cell("asyncio.run(asyncio.sleep(0.01)); 2")
     assert ip.user_ns["_"] == 2
     result = ip.run_cell("await asyncio.sleep(0.01); 3")
     assert ip.user_ns["_"] == 3
 
 
 def test_should_run_async():
     assert not ip.should_run_async("a = 5", transformed_cell="a = 5")
     assert ip.should_run_async("await x", transformed_cell="await x")
     assert ip.should_run_async(
         "import asyncio; await asyncio.sleep(1)",
         transformed_cell="import asyncio; await asyncio.sleep(1)",
     )
 
 
 def test_set_custom_completer():
     num_completers = len(ip.Completer.matchers)
 
     def foo(*args, **kwargs):
         return "I'm a completer!"
 
     ip.set_custom_completer(foo, 0)
 
     # check that we've really added a new completer
     assert len(ip.Completer.matchers) == num_completers + 1
 
     # check that the first completer is the function we defined
     assert ip.Completer.matchers[0]() == "I'm a completer!"
 
     # clean up
     ip.Completer.custom_matchers.pop()
 
 
 class TestShowTracebackAttack(unittest.TestCase):
     """Test that the interactive shell is resilient against the client attack of
     manipulating the showtracebacks method. These attacks shouldn't result in an
     unhandled exception in the kernel."""
 
     def setUp(self):
         self.orig_showtraceback = interactiveshell.InteractiveShell.showtraceback
 
     def tearDown(self):
         interactiveshell.InteractiveShell.showtraceback = self.orig_showtraceback
 
     def test_set_show_tracebacks_none(self):
         """Test the case of the client setting showtracebacks to None"""
 
         result = ip.run_cell(
             """
             import IPython.core.interactiveshell
             IPython.core.interactiveshell.InteractiveShell.showtraceback = None
 
             assert False, "This should not raise an exception"
         """
         )
         print(result)
 
         assert result.result is None
         assert isinstance(result.error_in_exec, TypeError)
         assert str(result.error_in_exec) == "'NoneType' object is not callable"
 
     def test_set_show_tracebacks_noop(self):
         """Test the case of the client setting showtracebacks to a no op lambda"""
 
         result = ip.run_cell(
             """
             import IPython.core.interactiveshell
             IPython.core.interactiveshell.InteractiveShell.showtraceback = lambda *args, **kwargs: None
 
             assert False, "This should not raise an exception"
         """
         )
         print(result)
 
         assert result.result is None
         assert isinstance(result.error_in_exec, AssertionError)
         assert str(result.error_in_exec) == "This should not raise an exception"

IPython/core/ultratb.py

@@ -1,1377 +1,1395 b''
 # -*- coding: utf-8 -*-
 """
 Verbose and colourful traceback formatting.
 
 **ColorTB**
 
 I've always found it a bit hard to visually parse tracebacks in Python.  The
 ColorTB class is a solution to that problem.  It colors the different parts of a
 traceback in a manner similar to what you would expect from a syntax-highlighting
 text editor.
 
 Installation instructions for ColorTB::
 
     import sys,ultratb
     sys.excepthook = ultratb.ColorTB()
 
 **VerboseTB**
 
 I've also included a port of Ka-Ping Yee's "cgitb.py" that produces all kinds
 of useful info when a traceback occurs.  Ping originally had it spit out HTML
 and intended it for CGI programmers, but why should they have all the fun?  I
 altered it to spit out colored text to the terminal.  It's a bit overwhelming,
 but kind of neat, and maybe useful for long-running programs that you believe
 are bug-free.  If a crash *does* occur in that type of program you want details.
 Give it a shot--you'll love it or you'll hate it.
 
 .. note::
 
   The Verbose mode prints the variables currently visible where the exception
   happened (shortening their strings if too long). This can potentially be
   very slow, if you happen to have a huge data structure whose string
   representation is complex to compute. Your computer may appear to freeze for
   a while with cpu usage at 100%. If this occurs, you can cancel the traceback
   with Ctrl-C (maybe hitting it more than once).
 
   If you encounter this kind of situation often, you may want to use the
   Verbose_novars mode instead of the regular Verbose, which avoids formatting
   variables (but otherwise includes the information and context given by
   Verbose).
 
 .. note::
 
   The verbose mode print all variables in the stack, which means it can
   potentially leak sensitive information like access keys, or unencrypted
   password.
 
 Installation instructions for VerboseTB::
 
     import sys,ultratb
     sys.excepthook = ultratb.VerboseTB()
 
 Note:  Much of the code in this module was lifted verbatim from the standard
 library module 'traceback.py' and Ka-Ping Yee's 'cgitb.py'.
 
 Color schemes
 -------------
 
 The colors are defined in the class TBTools through the use of the
 ColorSchemeTable class. Currently the following exist:
 
   - NoColor: allows all of this module to be used in any terminal (the color
     escapes are just dummy blank strings).
 
   - Linux: is meant to look good in a terminal like the Linux console (black
     or very dark background).
 
   - LightBG: similar to Linux but swaps dark/light colors to be more readable
     in light background terminals.
 
   - Neutral: a neutral color scheme that should be readable on both light and
     dark background
 
 You can implement other color schemes easily, the syntax is fairly
 self-explanatory. Please send back new schemes you develop to the author for
 possible inclusion in future releases.
 
 Inheritance diagram:
 
 .. inheritance-diagram:: IPython.core.ultratb
    :parts: 3
 """
 
 #*****************************************************************************
 # Copyright (C) 2001 Nathaniel Gray <[e-mail]>
 # Copyright (C) 2001-2004 Fernando Perez <[e-mail]>
 #
 # Distributed under the terms of the BSD License.  The full license is in
 # the file COPYING, distributed as part of this software.
 #*****************************************************************************
 
 
 import inspect
 import linecache
 import pydoc
 import sys
 import time
 import traceback
 from types import TracebackType
 from typing import Tuple, List, Any, Optional
 
 import stack_data
 from stack_data import FrameInfo as SDFrameInfo
 from pygments.formatters.terminal256 import Terminal256Formatter
 from pygments.styles import get_style_by_name
 
 # IPython's own modules
 from IPython import get_ipython
 from IPython.core import debugger
 from IPython.core.display_trap import DisplayTrap
 from IPython.core.excolors import exception_colors
 from IPython.utils import PyColorize
 from IPython.utils import path as util_path
 from IPython.utils import py3compat
 from IPython.utils.terminal import get_terminal_size
 
 import IPython.utils.colorable as colorable
 
 # Globals
 # amount of space to put line numbers before verbose tracebacks
 INDENT_SIZE = 8
 
 # Default color scheme.  This is used, for example, by the traceback
 # formatter.  When running in an actual IPython instance, the user's rc.colors
 # value is used, but having a module global makes this functionality available
 # to users of ultratb who are NOT running inside ipython.
 DEFAULT_SCHEME = 'NoColor'
 FAST_THRESHOLD = 10_000
 
 # ---------------------------------------------------------------------------
 # Code begins
 
 # Helper function -- largely belongs to VerboseTB, but we need the same
 # functionality to produce a pseudo verbose TB for SyntaxErrors, so that they
 # can be recognized properly by ipython.el's py-traceback-line-re
 # (SyntaxErrors have to be treated specially because they have no traceback)
 
 
 def _format_traceback_lines(lines, Colors, has_colors: bool, lvals):
     """
     Format tracebacks lines with pointing arrow, leading numbers...
 
     Parameters
     ----------
     lines : list[Line]
     Colors
         ColorScheme used.
     lvals : str
         Values of local variables, already colored, to inject just after the error line.
     """
     numbers_width = INDENT_SIZE - 1
     res = []
 
     for stack_line in lines:
         if stack_line is stack_data.LINE_GAP:
             res.append('%s   (...)%s\n' % (Colors.linenoEm, Colors.Normal))
             continue
 
         line = stack_line.render(pygmented=has_colors).rstrip('\n') + '\n'
         lineno = stack_line.lineno
         if stack_line.is_current:
             # This is the line with the error
             pad = numbers_width - len(str(lineno))
             num = '%s%s' % (debugger.make_arrow(pad), str(lineno))
             start_color = Colors.linenoEm
         else:
             num = '%*s' % (numbers_width, lineno)
             start_color = Colors.lineno
 
         line = '%s%s%s %s' % (start_color, num, Colors.Normal, line)
 
         res.append(line)
         if lvals and stack_line.is_current:
             res.append(lvals + '\n')
     return res
 
 def _simple_format_traceback_lines(lnum, index, lines, Colors, lvals, _line_format):
     """
     Format tracebacks lines with pointing arrow, leading numbers...
 
     Parameters
     ==========
 
     lnum: int
         number of the target line of code.
     index: int
         which line in the list should be highlighted.
     lines: list[string]
     Colors:
         ColorScheme used.
     lvals: bytes
         Values of local variables, already colored, to inject just after the error line.
     _line_format: f (str) -> (str, bool)
         return (colorized version of str, failure to do so)
     """
     numbers_width = INDENT_SIZE - 1
     res = []
 
     for i, line in enumerate(lines, lnum - index):
         line = py3compat.cast_unicode(line)
 
         new_line, err = _line_format(line, "str")
         if not err:
             line = new_line
 
         if i == lnum:
             # This is the line with the error
             pad = numbers_width - len(str(i))
             num = "%s%s" % (debugger.make_arrow(pad), str(lnum))
             line = "%s%s%s %s%s" % (
                 Colors.linenoEm,
                 num,
                 Colors.line,
                 line,
                 Colors.Normal,
             )
         else:
             num = "%*s" % (numbers_width, i)
             line = "%s%s%s %s" % (Colors.lineno, num, Colors.Normal, line)
 
         res.append(line)
         if lvals and i == lnum:
             res.append(lvals + "\n")
     return res
 
 
 def _format_filename(file, ColorFilename, ColorNormal, *, lineno=None):
     """
     Format filename lines with custom formatting from caching compiler or `File *.py` by default
 
     Parameters
     ----------
     file : str
     ColorFilename
         ColorScheme's filename coloring to be used.
     ColorNormal
         ColorScheme's normal coloring to be used.
     """
     ipinst = get_ipython()
     if (
         ipinst is not None
         and (data := ipinst.compile.format_code_name(file)) is not None
     ):
         label, name = data
         if lineno is None:
             tpl_link = f"{{label}} {ColorFilename}{{name}}{ColorNormal}"
         else:
             tpl_link = (
                 f"{{label}} {ColorFilename}{{name}}, line {{lineno}}{ColorNormal}"
             )
     else:
         label = "File"
         name = util_path.compress_user(
             py3compat.cast_unicode(file, util_path.fs_encoding)
         )
         if lineno is None:
             tpl_link = f"{{label}} {ColorFilename}{{name}}{ColorNormal}"
         else:
             # can we make this the more friendly ", line {{lineno}}", or do we need to preserve the formatting with the colon?
             tpl_link = f"{{label}} {ColorFilename}{{name}}:{{lineno}}{ColorNormal}"
 
     return tpl_link.format(label=label, name=name, lineno=lineno)
 
 #---------------------------------------------------------------------------
 # Module classes
 class TBTools(colorable.Colorable):
     """Basic tools used by all traceback printer classes."""
 
     # Number of frames to skip when reporting tracebacks
     tb_offset = 0
 
     def __init__(
         self,
         color_scheme="NoColor",
         call_pdb=False,
         ostream=None,
         parent=None,
         config=None,
         *,
         debugger_cls=None,
     ):
         # Whether to call the interactive pdb debugger after printing
         # tracebacks or not
         super(TBTools, self).__init__(parent=parent, config=config)
         self.call_pdb = call_pdb
 
         # Output stream to write to.  Note that we store the original value in
         # a private attribute and then make the public ostream a property, so
         # that we can delay accessing sys.stdout until runtime.  The way
         # things are written now, the sys.stdout object is dynamically managed
         # so a reference to it should NEVER be stored statically.  This
         # property approach confines this detail to a single location, and all
         # subclasses can simply access self.ostream for writing.
         self._ostream = ostream
 
         # Create color table
         self.color_scheme_table = exception_colors()
 
         self.set_colors(color_scheme)
         self.old_scheme = color_scheme  # save initial value for toggles
         self.debugger_cls = debugger_cls or debugger.Pdb
 
         if call_pdb:
             self.pdb = self.debugger_cls()
         else:
             self.pdb = None
 
     def _get_ostream(self):
         """Output stream that exceptions are written to.
 
         Valid values are:
 
         - None: the default, which means that IPython will dynamically resolve
           to sys.stdout.  This ensures compatibility with most tools, including
           Windows (where plain stdout doesn't recognize ANSI escapes).
 
         - Any object with 'write' and 'flush' attributes.
         """
         return sys.stdout if self._ostream is None else self._ostream
 
     def _set_ostream(self, val):
         assert val is None or (hasattr(val, 'write') and hasattr(val, 'flush'))
         self._ostream = val
 
     ostream = property(_get_ostream, _set_ostream)
 
     @staticmethod
     def _get_chained_exception(exception_value):
         cause = getattr(exception_value, "__cause__", None)
         if cause:
             return cause
         if getattr(exception_value, "__suppress_context__", False):
             return None
         return getattr(exception_value, "__context__", None)
 
     def get_parts_of_chained_exception(
         self, evalue
     ) -> Optional[Tuple[type, BaseException, TracebackType]]:
         chained_evalue = self._get_chained_exception(evalue)
 
         if chained_evalue:
             return chained_evalue.__class__, chained_evalue, chained_evalue.__traceback__
         return None
 
     def prepare_chained_exception_message(self, cause) -> List[Any]:
         direct_cause = "\nThe above exception was the direct cause of the following exception:\n"
         exception_during_handling = "\nDuring handling of the above exception, another exception occurred:\n"
 
         if cause:
             message = [[direct_cause]]
         else:
             message = [[exception_during_handling]]
         return message
 
     @property
     def has_colors(self) -> bool:
         return self.color_scheme_table.active_scheme_name.lower() != "nocolor"
 
     def set_colors(self, *args, **kw):
         """Shorthand access to the color table scheme selector method."""
 
         # Set own color table
         self.color_scheme_table.set_active_scheme(*args, **kw)
         # for convenience, set Colors to the active scheme
         self.Colors = self.color_scheme_table.active_colors
         # Also set colors of debugger
         if hasattr(self, 'pdb') and self.pdb is not None:
             self.pdb.set_colors(*args, **kw)
 
     def color_toggle(self):
         """Toggle between the currently active color scheme and NoColor."""
 
         if self.color_scheme_table.active_scheme_name == 'NoColor':
             self.color_scheme_table.set_active_scheme(self.old_scheme)
             self.Colors = self.color_scheme_table.active_colors
         else:
             self.old_scheme = self.color_scheme_table.active_scheme_name
             self.color_scheme_table.set_active_scheme('NoColor')
             self.Colors = self.color_scheme_table.active_colors
 
     def stb2text(self, stb):
         """Convert a structured traceback (a list) to a string."""
         return '\n'.join(stb)
 
     def text(self, etype, value, tb, tb_offset: Optional[int] = None, context=5):
         """Return formatted traceback.
 
         Subclasses may override this if they add extra arguments.
         """
         tb_list = self.structured_traceback(etype, value, tb,
                                             tb_offset, context)
         return self.stb2text(tb_list)
 
     def structured_traceback(
-        self, etype, evalue, tb, tb_offset: Optional[int] = None, context=5, mode=None
+        self,
+        etype: type,
+        evalue: Optional[BaseException],
+        etb: Optional[TracebackType] = None,
+        tb_offset: Optional[int] = None,
+        context=5,
     ):
         """Return a list of traceback frames.
 
         Must be implemented by each class.
         """
         raise NotImplementedError()
 
 
 #---------------------------------------------------------------------------
 class ListTB(TBTools):
     """Print traceback information from a traceback list, with optional color.
 
     Calling requires 3 arguments: (etype, evalue, elist)
     as would be obtained by::
 
       etype, evalue, tb = sys.exc_info()
       if tb:
         elist = traceback.extract_tb(tb)
       else:
         elist = None
 
     It can thus be used by programs which need to process the traceback before
     printing (such as console replacements based on the code module from the
     standard library).
 
     Because they are meant to be called without a full traceback (only a
     list), instances of this class can't call the interactive pdb debugger."""
 
 
     def __call__(self, etype, value, elist):
         self.ostream.flush()
         self.ostream.write(self.text(etype, value, elist))
         self.ostream.write('\n')
 
     def _extract_tb(self, tb):
         if tb:
             return traceback.extract_tb(tb)
         else:
             return None
 
     def structured_traceback(
         self,
         etype: type,
-        evalue: BaseException,
+        evalue: Optional[BaseException],
         etb: Optional[TracebackType] = None,
         tb_offset: Optional[int] = None,
         context=5,
     ):
         """Return a color formatted string with the traceback info.
 
         Parameters
         ----------
         etype : exception type
             Type of the exception raised.
         evalue : object
             Data stored in the exception
         etb : list | TracebackType | None
             If list: List of frames, see class docstring for details.
             If Traceback: Traceback of the exception.
         tb_offset : int, optional
             Number of frames in the traceback to skip.  If not given, the
             instance evalue is used (set in constructor).
         context : int, optional
             Number of lines of context information to print.
 
         Returns
         -------
         String with formatted exception.
         """
         # This is a workaround to get chained_exc_ids in recursive calls
         # etb should not be a tuple if structured_traceback is not recursive
         if isinstance(etb, tuple):
             etb, chained_exc_ids = etb
         else:
             chained_exc_ids = set()
 
         if isinstance(etb, list):
             elist = etb
         elif etb is not None:
             elist = self._extract_tb(etb)
         else:
             elist = []
         tb_offset = self.tb_offset if tb_offset is None else tb_offset
         assert isinstance(tb_offset, int)
         Colors = self.Colors
         out_list = []
         if elist:
 
             if tb_offset and len(elist) > tb_offset:
                 elist = elist[tb_offset:]
 
             out_list.append('Traceback %s(most recent call last)%s:' %
                             (Colors.normalEm, Colors.Normal) + '\n')
             out_list.extend(self._format_list(elist))
         # The exception info should be a single entry in the list.
         lines = ''.join(self._format_exception_only(etype, evalue))
         out_list.append(lines)
 
         exception = self.get_parts_of_chained_exception(evalue)
 
         if exception and not id(exception[1]) in chained_exc_ids:
-            chained_exception_message = self.prepare_chained_exception_message(
-                evalue.__cause__)[0]
+            chained_exception_message = (
+                self.prepare_chained_exception_message(evalue.__cause__)[0]
+                if evalue is not None
+                else ""
+            )
             etype, evalue, etb = exception
             # Trace exception to avoid infinite 'cause' loop
             chained_exc_ids.add(id(exception[1]))
             chained_exceptions_tb_offset = 0
             out_list = (
                 self.structured_traceback(
                     etype, evalue, (etb, chained_exc_ids),
                     chained_exceptions_tb_offset, context)
                 + chained_exception_message
                 + out_list)
 
         return out_list
 
     def _format_list(self, extracted_list):
         """Format a list of traceback entry tuples for printing.
 
         Given a list of tuples as returned by extract_tb() or
         extract_stack(), return a list of strings ready for printing.
         Each string in the resulting list corresponds to the item with the
         same index in the argument list.  Each string ends in a newline;
         the strings may contain internal newlines as well, for those items
         whose source text line is not None.
 
         Lifted almost verbatim from traceback.py
         """
 
         Colors = self.Colors
         list = []
         for ind, (filename, lineno, name, line) in enumerate(extracted_list):
             normalCol, nameCol, fileCol, lineCol = (
                 # Emphasize the last entry
                 (Colors.normalEm, Colors.nameEm, Colors.filenameEm, Colors.line)
                 if ind == len(extracted_list) - 1
                 else (Colors.Normal, Colors.name, Colors.filename, "")
             )
 
             fns = _format_filename(filename, fileCol, normalCol, lineno=lineno)
             item = f"{normalCol}  {fns}"
 
             if name != "<module>":
                 item += f" in {nameCol}{name}{normalCol}\n"
             else:
                 item += "\n"
             if line:
                 item += f"{lineCol}    {line.strip()}{normalCol}\n"
             list.append(item)
 
         return list
 
     def _format_exception_only(self, etype, value):
         """Format the exception part of a traceback.
 
         The arguments are the exception type and value such as given by
         sys.exc_info()[:2]. The return value is a list of strings, each ending
         in a newline.  Normally, the list contains a single string; however,
         for SyntaxError exceptions, it contains several lines that (when
         printed) display detailed information about where the syntax error
         occurred.  The message indicating which exception occurred is the
         always last string in the list.
 
         Also lifted nearly verbatim from traceback.py
         """
         have_filedata = False
         Colors = self.Colors
         list = []
         stype = py3compat.cast_unicode(Colors.excName + etype.__name__ + Colors.Normal)
         if value is None:
             # Not sure if this can still happen in Python 2.6 and above
             list.append(stype + '\n')
         else:
             if issubclass(etype, SyntaxError):
                 have_filedata = True
                 if not value.filename: value.filename = "<string>"
                 if value.lineno:
                     lineno = value.lineno
                     textline = linecache.getline(value.filename, value.lineno)
                 else:
                     lineno = "unknown"
                     textline = ""
                 list.append(
                     "%s  %s%s\n"
                     % (
                         Colors.normalEm,
                         _format_filename(
                             value.filename,
                             Colors.filenameEm,
                             Colors.normalEm,
                             lineno=(None if lineno == "unknown" else lineno),
                         ),
                         Colors.Normal,
                     )
                 )
                 if textline == "":
                     textline = py3compat.cast_unicode(value.text, "utf-8")
 
                 if textline is not None:
                     i = 0
                     while i < len(textline) and textline[i].isspace():
                         i += 1
                     list.append('%s    %s%s\n' % (Colors.line,
                                                   textline.strip(),
                                                   Colors.Normal))
                     if value.offset is not None:
                         s = '    '
                         for c in textline[i:value.offset - 1]:
                             if c.isspace():
                                 s += c
                             else:
                                 s += ' '
                         list.append('%s%s^%s\n' % (Colors.caret, s,
                                                    Colors.Normal))
 
             try:
                 s = value.msg
             except Exception:
                 s = self._some_str(value)
             if s:
                 list.append('%s%s:%s %s\n' % (stype, Colors.excName,
                                               Colors.Normal, s))
             else:
                 list.append('%s\n' % stype)
 
         # sync with user hooks
         if have_filedata:
             ipinst = get_ipython()
             if ipinst is not None:
                 ipinst.hooks.synchronize_with_editor(value.filename, value.lineno, 0)
 
         return list
 
     def get_exception_only(self, etype, value):
         """Only print the exception type and message, without a traceback.
 
         Parameters
         ----------
         etype : exception type
         value : exception value
         """
         return ListTB.structured_traceback(self, etype, value)
 
     def show_exception_only(self, etype, evalue):
         """Only print the exception type and message, without a traceback.
 
         Parameters
         ----------
         etype : exception type
         evalue : exception value
         """
         # This method needs to use __call__ from *this* class, not the one from
         # a subclass whose signature or behavior may be different
         ostream = self.ostream
         ostream.flush()
         ostream.write('\n'.join(self.get_exception_only(etype, evalue)))
         ostream.flush()
 
     def _some_str(self, value):
         # Lifted from traceback.py
         try:
             return py3compat.cast_unicode(str(value))
         except:
             return u'<unprintable %s object>' % type(value).__name__
 
 
 class FrameInfo:
     """
     Mirror of stack data's FrameInfo, but so that we can bypass highlighting on
     really long frames.
     """
 
     description: Optional[str]
     filename: str
     lineno: int
 
     @classmethod
     def _from_stack_data_FrameInfo(cls, frame_info):
         return cls(
             getattr(frame_info, "description", None),
             getattr(frame_info, "filename", None),
             getattr(frame_info, "lineno", None),
             getattr(frame_info, "frame", None),
             getattr(frame_info, "code", None),
             sd=frame_info,
         )
 
     def __init__(self, description, filename, lineno, frame, code, sd=None):
         self.description = description
         self.filename = filename
         self.lineno = lineno
         self.frame = frame
         self.code = code
         self._sd = sd
 
         # self.lines = []
         if sd is None:
             ix = inspect.getsourcelines(frame)
             self.raw_lines = ix[0]
 
     @property
     def variables_in_executing_piece(self):
         if self._sd:
             return self._sd.variables_in_executing_piece
         else:
             return []
 
     @property
     def lines(self):
         return self._sd.lines
 
     @property
     def executing(self):
         if self._sd:
             return self._sd.executing
         else:
             return None
 
 
 # ----------------------------------------------------------------------------
 class VerboseTB(TBTools):
     """A port of Ka-Ping Yee's cgitb.py module that outputs color text instead
     of HTML.  Requires inspect and pydoc.  Crazy, man.
 
     Modified version which optionally strips the topmost entries from the
     traceback, to be used with alternate interpreters (because their own code
     would appear in the traceback)."""
 
     _tb_highlight = "bg:ansiyellow"
 
     def __init__(
         self,
         color_scheme: str = "Linux",
         call_pdb: bool = False,
         ostream=None,
         tb_offset: int = 0,
         long_header: bool = False,
         include_vars: bool = True,
         check_cache=None,
         debugger_cls=None,
         parent=None,
         config=None,
     ):
         """Specify traceback offset, headers and color scheme.
 
         Define how many frames to drop from the tracebacks. Calling it with
         tb_offset=1 allows use of this handler in interpreters which will have
         their own code at the top of the traceback (VerboseTB will first
         remove that frame before printing the traceback info)."""
         TBTools.__init__(
             self,
             color_scheme=color_scheme,
             call_pdb=call_pdb,
             ostream=ostream,
             parent=parent,
             config=config,
             debugger_cls=debugger_cls,
         )
         self.tb_offset = tb_offset
         self.long_header = long_header
         self.include_vars = include_vars
         # By default we use linecache.checkcache, but the user can provide a
         # different check_cache implementation.  This was formerly used by the
         # IPython kernel for interactive code, but is no longer necessary.
         if check_cache is None:
             check_cache = linecache.checkcache
         self.check_cache = check_cache
 
         self.skip_hidden = True
 
     def format_record(self, frame_info: FrameInfo):
         """Format a single stack frame"""
         assert isinstance(frame_info, FrameInfo)
         Colors = self.Colors  # just a shorthand + quicker name lookup
         ColorsNormal = Colors.Normal  # used a lot
 
         if isinstance(frame_info._sd, stack_data.RepeatedFrames):
             return '    %s[... skipping similar frames: %s]%s\n' % (
                 Colors.excName, frame_info.description, ColorsNormal)
 
         indent = " " * INDENT_SIZE
         em_normal = "%s\n%s%s" % (Colors.valEm, indent, ColorsNormal)
         tpl_call = f"in {Colors.vName}{{file}}{Colors.valEm}{{scope}}{ColorsNormal}"
         tpl_call_fail = "in %s%%s%s(***failed resolving arguments***)%s" % (
             Colors.vName,
             Colors.valEm,
             ColorsNormal,
         )
         tpl_name_val = "%%s %s= %%s%s" % (Colors.valEm, ColorsNormal)
 
         link = _format_filename(
             frame_info.filename,
             Colors.filenameEm,
             ColorsNormal,
             lineno=frame_info.lineno,
         )
         args, varargs, varkw, locals_ = inspect.getargvalues(frame_info.frame)
         if frame_info.executing is not None:
             func = frame_info.executing.code_qualname()
         else:
             func = "?"
         if func == "<module>":
             call = ""
         else:
             # Decide whether to include variable details or not
             var_repr = eqrepr if self.include_vars else nullrepr
             try:
                 scope = inspect.formatargvalues(
                     args, varargs, varkw, locals_, formatvalue=var_repr
                 )
                 call = tpl_call.format(file=func, scope=scope)
             except KeyError:
                 # This happens in situations like errors inside generator
                 # expressions, where local variables are listed in the
                 # line, but can't be extracted from the frame.  I'm not
                 # 100% sure this isn't actually a bug in inspect itself,
                 # but since there's no info for us to compute with, the
                 # best we can do is report the failure and move on.  Here
                 # we must *not* call any traceback construction again,
                 # because that would mess up use of %debug later on.  So we
                 # simply report the failure and move on.  The only
                 # limitation will be that this frame won't have locals
                 # listed in the call signature.  Quite subtle problem...
                 # I can't think of a good way to validate this in a unit
                 # test, but running a script consisting of:
                 #  dict( (k,v.strip()) for (k,v) in range(10) )
                 # will illustrate the error, if this exception catch is
                 # disabled.
                 call = tpl_call_fail % func
 
         lvals = ''
         lvals_list = []
         if self.include_vars:
             try:
                 # we likely want to fix stackdata at some point, but
                 # still need a workaround.
                 fibp = frame_info.variables_in_executing_piece
                 for var in fibp:
                     lvals_list.append(tpl_name_val % (var.name, repr(var.value)))
             except Exception:
                 lvals_list.append(
                     "Exception trying to inspect frame. No more locals available."
                 )
         if lvals_list:
             lvals = '%s%s' % (indent, em_normal.join(lvals_list))
 
         result = f'{link}{", " if call else ""}{call}\n'
         if frame_info._sd is None:
             assert False
             # fast fallback if file is too long
             tpl_link = "%s%%s%s" % (Colors.filenameEm, ColorsNormal)
             link = tpl_link % util_path.compress_user(frame_info.filename)
             level = "%s %s\n" % (link, call)
             _line_format = PyColorize.Parser(
                 style=self.color_scheme_table.active_scheme_name, parent=self
             ).format2
             first_line = frame_info.code.co_firstlineno
             current_line = frame_info.lineno[0]
             return "%s%s" % (
                 level,
                 "".join(
                     _simple_format_traceback_lines(
                         current_line,
                         current_line - first_line,
                         frame_info.raw_lines,
                         Colors,
                         lvals,
                         _line_format,
                     )
                 ),
             )
             # result += "\n".join(frame_info.raw_lines)
         else:
             result += "".join(
                 _format_traceback_lines(
                     frame_info.lines, Colors, self.has_colors, lvals
                 )
             )
         return result
 
-    def prepare_header(self, etype, long_version=False):
+    def prepare_header(self, etype: str, long_version: bool = False):
         colors = self.Colors  # just a shorthand + quicker name lookup
         colorsnormal = colors.Normal  # used a lot
         exc = '%s%s%s' % (colors.excName, etype, colorsnormal)
         width = min(75, get_terminal_size()[0])
         if long_version:
             # Header with the exception type, python version, and date
             pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
             date = time.ctime(time.time())
 
-            head = '%s%s%s\n%s%s%s\n%s' % (colors.topline, '-' * width, colorsnormal,
-                                           exc, ' ' * (width - len(str(etype)) - len(pyver)),
-                                           pyver, date.rjust(width) )
-            head += "\nA problem occurred executing Python code.  Here is the sequence of function" \
-                    "\ncalls leading up to the error, with the most recent (innermost) call last."
+            head = "%s%s%s\n%s%s%s\n%s" % (
+                colors.topline,
+                "-" * width,
+                colorsnormal,
+                exc,
+                " " * (width - len(etype) - len(pyver)),
+                pyver,
+                date.rjust(width),
+            )
+            head += (
+                "\nA problem occurred executing Python code.  Here is the sequence of function"
+                "\ncalls leading up to the error, with the most recent (innermost) call last."
+            )
         else:
             # Simplified header
-            head = '%s%s' % (exc, 'Traceback (most recent call last)'. \
-                             rjust(width - len(str(etype))) )
+            head = "%s%s" % (
+                exc,
+                "Traceback (most recent call last)".rjust(width - len(etype)),
+            )
 
         return head
 
     def format_exception(self, etype, evalue):
         colors = self.Colors  # just a shorthand + quicker name lookup
         colorsnormal = colors.Normal  # used a lot
         # Get (safely) a string form of the exception info
         try:
             etype_str, evalue_str = map(str, (etype, evalue))
         except:
             # User exception is improperly defined.
             etype, evalue = str, sys.exc_info()[:2]
             etype_str, evalue_str = map(str, (etype, evalue))
         # ... and format it
         return ['%s%s%s: %s' % (colors.excName, etype_str,
                                 colorsnormal, py3compat.cast_unicode(evalue_str))]
 
     def format_exception_as_a_whole(
         self,
         etype: type,
-        evalue: BaseException,
+        evalue: Optional[BaseException],
         etb: Optional[TracebackType],
         number_of_lines_of_context,
         tb_offset: Optional[int],
     ):
         """Formats the header, traceback and exception message for a single exception.
 
         This may be called multiple times by Python 3 exception chaining
         (PEP 3134).
         """
         # some locals
         orig_etype = etype
         try:
             etype = etype.__name__
         except AttributeError:
             pass
 
         tb_offset = self.tb_offset if tb_offset is None else tb_offset
         assert isinstance(tb_offset, int)
         head = self.prepare_header(etype, self.long_header)
         records = (
             self.get_records(etb, number_of_lines_of_context, tb_offset) if etb else []
         )
 
         frames = []
         skipped = 0
         lastrecord = len(records) - 1
         for i, record in enumerate(records):
             if (
                 not isinstance(record._sd, stack_data.RepeatedFrames)
                 and self.skip_hidden
             ):
                 if (
                     record.frame.f_locals.get("__tracebackhide__", 0)
                     and i != lastrecord
                 ):
                     skipped += 1
                     continue
             if skipped:
                 Colors = self.Colors  # just a shorthand + quicker name lookup
                 ColorsNormal = Colors.Normal  # used a lot
                 frames.append(
                     "    %s[... skipping hidden %s frame]%s\n"
                     % (Colors.excName, skipped, ColorsNormal)
                 )
                 skipped = 0
             frames.append(self.format_record(record))
         if skipped:
             Colors = self.Colors  # just a shorthand + quicker name lookup
             ColorsNormal = Colors.Normal  # used a lot
             frames.append(
                 "    %s[... skipping hidden %s frame]%s\n"
                 % (Colors.excName, skipped, ColorsNormal)
             )
 
         formatted_exception = self.format_exception(etype, evalue)
         if records:
             frame_info = records[-1]
             ipinst = get_ipython()
             if ipinst is not None:
                 ipinst.hooks.synchronize_with_editor(frame_info.filename, frame_info.lineno, 0)
 
         return [[head] + frames + [''.join(formatted_exception[0])]]
 
     def get_records(
         self, etb: TracebackType, number_of_lines_of_context: int, tb_offset: int
     ):
         assert etb is not None
         context = number_of_lines_of_context - 1
         after = context // 2
         before = context - after
         if self.has_colors:
             style = get_style_by_name("default")
             style = stack_data.style_with_executing_node(style, self._tb_highlight)
             formatter = Terminal256Formatter(style=style)
         else:
             formatter = None
         options = stack_data.Options(
             before=before,
             after=after,
             pygments_formatter=formatter,
         )
 
         # Let's estimate the amount of code we will have to parse/highlight.
-        cf = etb
+        cf: Optional[TracebackType] = etb
         max_len = 0
         tbs = []
         while cf is not None:
             source_file = inspect.getsourcefile(etb.tb_frame)
             lines, first = inspect.getsourcelines(etb.tb_frame)
             max_len = max(max_len, first + len(lines))
             tbs.append(cf)
             cf = cf.tb_next
 
         if max_len > FAST_THRESHOLD:
             FIs = []
             for tb in tbs:
                 frame = tb.tb_frame
                 lineno = (frame.f_lineno,)
                 code = frame.f_code
                 filename = code.co_filename
                 FIs.append(FrameInfo("Raw frame", filename, lineno, frame, code))
             return FIs
         res = list(stack_data.FrameInfo.stack_data(etb, options=options))[tb_offset:]
         res = [FrameInfo._from_stack_data_FrameInfo(r) for r in res]
         return res
 
     def structured_traceback(
         self,
         etype: type,
         evalue: Optional[BaseException],
         etb: Optional[TracebackType],
         tb_offset: Optional[int] = None,
         number_of_lines_of_context: int = 5,
     ):
         """Return a nice text document describing the traceback."""
         formatted_exception = self.format_exception_as_a_whole(etype, evalue, etb, number_of_lines_of_context,
                                                                tb_offset)
 
         colors = self.Colors  # just a shorthand + quicker name lookup
         colorsnormal = colors.Normal  # used a lot
         head = '%s%s%s' % (colors.topline, '-' * min(75, get_terminal_size()[0]), colorsnormal)
         structured_traceback_parts = [head]
         chained_exceptions_tb_offset = 0
         lines_of_context = 3
         formatted_exceptions = formatted_exception
         exception = self.get_parts_of_chained_exception(evalue)
         if exception:
             assert evalue is not None
             formatted_exceptions += self.prepare_chained_exception_message(evalue.__cause__)
             etype, evalue, etb = exception
         else:
             evalue = None
         chained_exc_ids = set()
         while evalue:
             formatted_exceptions += self.format_exception_as_a_whole(etype, evalue, etb, lines_of_context,
                                                                      chained_exceptions_tb_offset)
             exception = self.get_parts_of_chained_exception(evalue)
 
             if exception and not id(exception[1]) in chained_exc_ids:
                 chained_exc_ids.add(id(exception[1])) # trace exception to avoid infinite 'cause' loop
                 formatted_exceptions += self.prepare_chained_exception_message(evalue.__cause__)
                 etype, evalue, etb = exception
             else:
                 evalue = None
 
         # we want to see exceptions in a reversed order:
         # the first exception should be on top
         for formatted_exception in reversed(formatted_exceptions):
             structured_traceback_parts += formatted_exception
 
         return structured_traceback_parts
 
     def debugger(self, force: bool = False):
         """Call up the pdb debugger if desired, always clean up the tb
         reference.
 
         Keywords:
 
           - force(False): by default, this routine checks the instance call_pdb
             flag and does not actually invoke the debugger if the flag is false.
             The 'force' option forces the debugger to activate even if the flag
             is false.
 
         If the call_pdb flag is set, the pdb interactive debugger is
         invoked. In all cases, the self.tb reference to the current traceback
         is deleted to prevent lingering references which hamper memory
         management.
 
         Note that each call to pdb() does an 'import readline', so if your app
         requires a special setup for the readline completers, you'll have to
         fix that by hand after invoking the exception handler."""
 
         if force or self.call_pdb:
             if self.pdb is None:
                 self.pdb = self.debugger_cls()
             # the system displayhook may have changed, restore the original
             # for pdb
             display_trap = DisplayTrap(hook=sys.__displayhook__)
             with display_trap:
                 self.pdb.reset()
                 # Find the right frame so we don't pop up inside ipython itself
                 if hasattr(self, 'tb') and self.tb is not None:
                     etb = self.tb
                 else:
                     etb = self.tb = sys.last_traceback
                 while self.tb is not None and self.tb.tb_next is not None:
                     assert self.tb.tb_next is not None
                     self.tb = self.tb.tb_next
                 if etb and etb.tb_next:
                     etb = etb.tb_next
                 self.pdb.botframe = etb.tb_frame
                 self.pdb.interaction(None, etb)
 
         if hasattr(self, 'tb'):
             del self.tb
 
     def handler(self, info=None):
         (etype, evalue, etb) = info or sys.exc_info()
         self.tb = etb
         ostream = self.ostream
         ostream.flush()
         ostream.write(self.text(etype, evalue, etb))
         ostream.write('\n')
         ostream.flush()
 
     # Changed so an instance can just be called as VerboseTB_inst() and print
     # out the right info on its own.
     def __call__(self, etype=None, evalue=None, etb=None):
         """This hook can replace sys.excepthook (for Python 2.1 or higher)."""
         if etb is None:
             self.handler()
         else:
             self.handler((etype, evalue, etb))
         try:
             self.debugger()
         except KeyboardInterrupt:
             print("\nKeyboardInterrupt")
 
 
 #----------------------------------------------------------------------------
 class FormattedTB(VerboseTB, ListTB):
     """Subclass ListTB but allow calling with a traceback.
 
     It can thus be used as a sys.excepthook for Python > 2.1.
 
     Also adds 'Context' and 'Verbose' modes, not available in ListTB.
 
     Allows a tb_offset to be specified. This is useful for situations where
     one needs to remove a number of topmost frames from the traceback (such as
     occurs with python programs that themselves execute other python code,
     like Python shells).  """
 
     mode: str
 
     def __init__(self, mode='Plain', color_scheme='Linux', call_pdb=False,
                  ostream=None,
                  tb_offset=0, long_header=False, include_vars=False,
                  check_cache=None, debugger_cls=None,
                  parent=None, config=None):
 
         # NEVER change the order of this list. Put new modes at the end:
         self.valid_modes = ['Plain', 'Context', 'Verbose', 'Minimal']
         self.verbose_modes = self.valid_modes[1:3]
 
         VerboseTB.__init__(self, color_scheme=color_scheme, call_pdb=call_pdb,
                            ostream=ostream, tb_offset=tb_offset,
                            long_header=long_header, include_vars=include_vars,
                            check_cache=check_cache, debugger_cls=debugger_cls,
                            parent=parent, config=config)
 
         # Different types of tracebacks are joined with different separators to
         # form a single string.  They are taken from this dict
         self._join_chars = dict(Plain='', Context='\n', Verbose='\n',
                                 Minimal='')
         # set_mode also sets the tb_join_char attribute
         self.set_mode(mode)
 
     def structured_traceback(self, etype, value, tb, tb_offset=None, number_of_lines_of_context=5):
         tb_offset = self.tb_offset if tb_offset is None else tb_offset
         mode = self.mode
         if mode in self.verbose_modes:
             # Verbose modes need a full traceback
             return VerboseTB.structured_traceback(
                 self, etype, value, tb, tb_offset, number_of_lines_of_context
             )
         elif mode == 'Minimal':
             return ListTB.get_exception_only(self, etype, value)
         else:
             # We must check the source cache because otherwise we can print
             # out-of-date source code.
             self.check_cache()
             # Now we can extract and format the exception
             return ListTB.structured_traceback(
                 self, etype, value, tb, tb_offset, number_of_lines_of_context
             )
 
     def stb2text(self, stb):
         """Convert a structured traceback (a list) to a string."""
         return self.tb_join_char.join(stb)
 
     def set_mode(self, mode: Optional[str] = None):
         """Switch to the desired mode.
 
         If mode is not specified, cycles through the available modes."""
 
         if not mode:
             new_idx = (self.valid_modes.index(self.mode) + 1 ) % \
                       len(self.valid_modes)
             self.mode = self.valid_modes[new_idx]
         elif mode not in self.valid_modes:
             raise ValueError(
                 "Unrecognized mode in FormattedTB: <" + mode + ">\n"
                 "Valid modes: " + str(self.valid_modes)
             )
         else:
             assert isinstance(mode, str)
             self.mode = mode
         # include variable details only in 'Verbose' mode
         self.include_vars = (self.mode == self.valid_modes[2])
         # Set the join character for generating text tracebacks
         self.tb_join_char = self._join_chars[self.mode]
 
     # some convenient shortcuts
     def plain(self):
         self.set_mode(self.valid_modes[0])
 
     def context(self):
         self.set_mode(self.valid_modes[1])
 
     def verbose(self):
         self.set_mode(self.valid_modes[2])
 
     def minimal(self):
         self.set_mode(self.valid_modes[3])
 
 
 #----------------------------------------------------------------------------
 class AutoFormattedTB(FormattedTB):
     """A traceback printer which can be called on the fly.
 
     It will find out about exceptions by itself.
 
     A brief example::
 
         AutoTB = AutoFormattedTB(mode = 'Verbose',color_scheme='Linux')
         try:
           ...
         except:
           AutoTB()  # or AutoTB(out=logfile) where logfile is an open file object
     """
 
     def __call__(self, etype=None, evalue=None, etb=None,
                  out=None, tb_offset=None):
         """Print out a formatted exception traceback.
 
         Optional arguments:
           - out: an open file-like object to direct output to.
 
           - tb_offset: the number of frames to skip over in the stack, on a
           per-call basis (this overrides temporarily the instance's tb_offset
           given at initialization time."""
 
         if out is None:
             out = self.ostream
         out.flush()
         out.write(self.text(etype, evalue, etb, tb_offset))
         out.write('\n')
         out.flush()
         # FIXME: we should remove the auto pdb behavior from here and leave
         # that to the clients.
         try:
             self.debugger()
         except KeyboardInterrupt:
             print("\nKeyboardInterrupt")
 
     def structured_traceback(
         self,
         etype=None,
         value=None,
         tb=None,
         tb_offset=None,
         number_of_lines_of_context=5,
     ):
         etype: type
         value: BaseException
         # tb: TracebackType or tupleof tb types ?
         if etype is None:
             etype, value, tb = sys.exc_info()
         if isinstance(tb, tuple):
             # tb is a tuple if this is a chained exception.
             self.tb = tb[0]
         else:
             self.tb = tb
         return FormattedTB.structured_traceback(
             self, etype, value, tb, tb_offset, number_of_lines_of_context)
 
 
 #---------------------------------------------------------------------------
 
 # A simple class to preserve Nathan's original functionality.
 class ColorTB(FormattedTB):
     """Shorthand to initialize a FormattedTB in Linux colors mode."""
 
     def __init__(self, color_scheme='Linux', call_pdb=0, **kwargs):
         FormattedTB.__init__(self, color_scheme=color_scheme,
                              call_pdb=call_pdb, **kwargs)
 
 
 class SyntaxTB(ListTB):
     """Extension which holds some state: the last exception value"""
 
     def __init__(self, color_scheme='NoColor', parent=None, config=None):
         ListTB.__init__(self, color_scheme, parent=parent, config=config)
         self.last_syntax_error = None
 
     def __call__(self, etype, value, elist):
         self.last_syntax_error = value
 
         ListTB.__call__(self, etype, value, elist)
 
     def structured_traceback(self, etype, value, elist, tb_offset=None,
                              context=5):
         # If the source file has been edited, the line in the syntax error can
         # be wrong (retrieved from an outdated cache). This replaces it with
         # the current value.
         if isinstance(value, SyntaxError) \
                 and isinstance(value.filename, str) \
                 and isinstance(value.lineno, int):
             linecache.checkcache(value.filename)
             newtext = linecache.getline(value.filename, value.lineno)
             if newtext:
                 value.text = newtext
         self.last_syntax_error = value
         return super(SyntaxTB, self).structured_traceback(etype, value, elist,
                                                           tb_offset=tb_offset, context=context)
 
     def clear_err_state(self):
         """Return the current error state and clear it"""
         e = self.last_syntax_error
         self.last_syntax_error = None
         return e
 
     def stb2text(self, stb):
         """Convert a structured traceback (a list) to a string."""
         return ''.join(stb)
 
 
 # some internal-use functions
 def text_repr(value):
     """Hopefully pretty robust repr equivalent."""
     # this is pretty horrible but should always return *something*
     try:
         return pydoc.text.repr(value)
     except KeyboardInterrupt:
         raise
     except:
         try:
             return repr(value)
         except KeyboardInterrupt:
             raise
         except:
             try:
                 # all still in an except block so we catch
                 # getattr raising
                 name = getattr(value, '__name__', None)
                 if name:
                     # ick, recursion
                     return text_repr(name)
                 klass = getattr(value, '__class__', None)
                 if klass:
                     return '%s instance' % text_repr(klass)
             except KeyboardInterrupt:
                 raise
             except:
                 return 'UNRECOVERABLE REPR FAILURE'
 
 
 def eqrepr(value, repr=text_repr):
     return '=%s' % repr(value)
 
 
 def nullrepr(value, repr=text_repr):
     return ''

IPython/lib/display.py

@@ -1,675 +1,677 b''
 """Various display related classes.
 
 Authors : MinRK, gregcaporaso, dannystaple
 """
 from html import escape as html_escape
 from os.path import exists, isfile, splitext, abspath, join, isdir
 from os import walk, sep, fsdecode
 
 from IPython.core.display import DisplayObject, TextDisplayObject
 
-from typing import Tuple, Iterable
+from typing import Tuple, Iterable, Optional
 
 __all__ = ['Audio', 'IFrame', 'YouTubeVideo', 'VimeoVideo', 'ScribdDocument',
            'FileLink', 'FileLinks', 'Code']
 
 
 class Audio(DisplayObject):
     """Create an audio object.
 
     When this object is returned by an input cell or passed to the
     display function, it will result in Audio controls being displayed
     in the frontend (only works in the notebook).
 
     Parameters
     ----------
     data : numpy array, list, unicode, str or bytes
         Can be one of
 
           * Numpy 1d array containing the desired waveform (mono)
           * Numpy 2d array containing waveforms for each channel.
             Shape=(NCHAN, NSAMPLES). For the standard channel order, see
             http://msdn.microsoft.com/en-us/library/windows/hardware/dn653308(v=vs.85).aspx
           * List of float or integer representing the waveform (mono)
           * String containing the filename
           * Bytestring containing raw PCM data or
           * URL pointing to a file on the web.
 
         If the array option is used, the waveform will be normalized.
 
         If a filename or url is used, the format support will be browser
         dependent.
     url : unicode
         A URL to download the data from.
     filename : unicode
         Path to a local file to load the data from.
     embed : boolean
         Should the audio data be embedded using a data URI (True) or should
         the original source be referenced. Set this to True if you want the
         audio to playable later with no internet connection in the notebook.
 
         Default is `True`, unless the keyword argument `url` is set, then
         default value is `False`.
     rate : integer
         The sampling rate of the raw data.
         Only required when data parameter is being used as an array
     autoplay : bool
         Set to True if the audio should immediately start playing.
         Default is `False`.
     normalize : bool
         Whether audio should be normalized (rescaled) to the maximum possible
         range. Default is `True`. When set to `False`, `data` must be between
         -1 and 1 (inclusive), otherwise an error is raised.
         Applies only when `data` is a list or array of samples; other types of
         audio are never normalized.
 
     Examples
     --------
 
     >>> import pytest
     >>> np = pytest.importorskip("numpy")
 
     Generate a sound
 
     >>> import numpy as np
     >>> framerate = 44100
     >>> t = np.linspace(0,5,framerate*5)
     >>> data = np.sin(2*np.pi*220*t) + np.sin(2*np.pi*224*t)
     >>> Audio(data, rate=framerate)
     <IPython.lib.display.Audio object>
 
     Can also do stereo or more channels
 
     >>> dataleft = np.sin(2*np.pi*220*t)
     >>> dataright = np.sin(2*np.pi*224*t)
     >>> Audio([dataleft, dataright], rate=framerate)
     <IPython.lib.display.Audio object>
 
     From URL:
 
     >>> Audio("http://www.nch.com.au/acm/8k16bitpcm.wav")  # doctest: +SKIP
     >>> Audio(url="http://www.w3schools.com/html/horse.ogg")  # doctest: +SKIP
 
     From a File:
 
     >>> Audio('IPython/lib/tests/test.wav')  # doctest: +SKIP
     >>> Audio(filename='IPython/lib/tests/test.wav')  # doctest: +SKIP
 
     From Bytes:
 
     >>> Audio(b'RAW_WAV_DATA..')  # doctest: +SKIP
     >>> Audio(data=b'RAW_WAV_DATA..')  # doctest: +SKIP
 
     See Also
     --------
     ipywidgets.Audio
 
          Audio widget with more more flexibility and options.
 
     """
     _read_flags = 'rb'
 
     def __init__(self, data=None, filename=None, url=None, embed=None, rate=None, autoplay=False, normalize=True, *,
                  element_id=None):
         if filename is None and url is None and data is None:
             raise ValueError("No audio data found. Expecting filename, url, or data.")
         if embed is False and url is None:
             raise ValueError("No url found. Expecting url when embed=False")
 
         if url is not None and embed is not True:
             self.embed = False
         else:
             self.embed = True
         self.autoplay = autoplay
         self.element_id = element_id
         super(Audio, self).__init__(data=data, url=url, filename=filename)
 
         if self.data is not None and not isinstance(self.data, bytes):
             if rate is None:
                 raise ValueError("rate must be specified when data is a numpy array or list of audio samples.")
             self.data = Audio._make_wav(data, rate, normalize)
 
     def reload(self):
         """Reload the raw data from file or URL."""
         import mimetypes
         if self.embed:
             super(Audio, self).reload()
 
         if self.filename is not None:
             self.mimetype = mimetypes.guess_type(self.filename)[0]
         elif self.url is not None:
             self.mimetype = mimetypes.guess_type(self.url)[0]
         else:
             self.mimetype = "audio/wav"
 
     @staticmethod
     def _make_wav(data, rate, normalize):
         """ Transform a numpy array to a PCM bytestring """
         from io import BytesIO
         import wave
 
         try:
             scaled, nchan = Audio._validate_and_normalize_with_numpy(data, normalize)
         except ImportError:
             scaled, nchan = Audio._validate_and_normalize_without_numpy(data, normalize)
 
         fp = BytesIO()
         waveobj = wave.open(fp,mode='wb')
         waveobj.setnchannels(nchan)
         waveobj.setframerate(rate)
         waveobj.setsampwidth(2)
         waveobj.setcomptype('NONE','NONE')
         waveobj.writeframes(scaled)
         val = fp.getvalue()
         waveobj.close()
 
         return val
 
     @staticmethod
     def _validate_and_normalize_with_numpy(data, normalize) -> Tuple[bytes, int]:
         import numpy as np
 
         data = np.array(data, dtype=float)
         if len(data.shape) == 1:
             nchan = 1
         elif len(data.shape) == 2:
             # In wave files,channels are interleaved. E.g.,
             # "L1R1L2R2..." for stereo. See
             # http://msdn.microsoft.com/en-us/library/windows/hardware/dn653308(v=vs.85).aspx
             # for channel ordering
             nchan = data.shape[0]
             data = data.T.ravel()
         else:
             raise ValueError('Array audio input must be a 1D or 2D array')
         
         max_abs_value = np.max(np.abs(data))
         normalization_factor = Audio._get_normalization_factor(max_abs_value, normalize)
         scaled = data / normalization_factor * 32767
         return scaled.astype("<h").tobytes(), nchan
 
     @staticmethod
     def _validate_and_normalize_without_numpy(data, normalize):
         import array
         import sys
 
         data = array.array('f', data)
 
         try:
             max_abs_value = float(max([abs(x) for x in data]))
         except TypeError as e:
             raise TypeError('Only lists of mono audio are '
                 'supported if numpy is not installed') from e
 
         normalization_factor = Audio._get_normalization_factor(max_abs_value, normalize)
         scaled = array.array('h', [int(x / normalization_factor * 32767) for x in data])
         if sys.byteorder == 'big':
             scaled.byteswap()
         nchan = 1
         return scaled.tobytes(), nchan
 
     @staticmethod
     def _get_normalization_factor(max_abs_value, normalize):
         if not normalize and max_abs_value > 1:
             raise ValueError('Audio data must be between -1 and 1 when normalize=False.')
         return max_abs_value if normalize else 1
 
     def _data_and_metadata(self):
         """shortcut for returning metadata with url information, if defined"""
         md = {}
         if self.url:
             md['url'] = self.url
         if md:
             return self.data, md
         else:
             return self.data
 
     def _repr_html_(self):
         src = """
                 <audio {element_id} controls="controls" {autoplay}>
                     <source src="{src}" type="{type}" />
                     Your browser does not support the audio element.
                 </audio>
               """
         return src.format(src=self.src_attr(), type=self.mimetype, autoplay=self.autoplay_attr(),
                           element_id=self.element_id_attr())
 
     def src_attr(self):
         import base64
         if self.embed and (self.data is not None):
             data = base64=base64.b64encode(self.data).decode('ascii')
             return """data:{type};base64,{base64}""".format(type=self.mimetype,
                                                             base64=data)
         elif self.url is not None:
             return self.url
         else:
             return ""
 
     def autoplay_attr(self):
         if(self.autoplay):
             return 'autoplay="autoplay"'
         else:
             return ''
     
     def element_id_attr(self):
         if (self.element_id):
             return 'id="{element_id}"'.format(element_id=self.element_id)
         else:
             return ''
 
 class IFrame(object):
     """
     Generic class to embed an iframe in an IPython notebook
     """
 
     iframe = """
         <iframe
             width="{width}"
             height="{height}"
             src="{src}{params}"
             frameborder="0"
             allowfullscreen
             {extras}
         ></iframe>
         """
 
-    def __init__(self, src, width, height, extras: Iterable[str] = None, **kwargs):
+    def __init__(
+        self, src, width, height, extras: Optional[Iterable[str]] = None, **kwargs
+    ):
         if extras is None:
             extras = []
 
         self.src = src
         self.width = width
         self.height = height
         self.extras = extras
         self.params = kwargs
 
     def _repr_html_(self):
         """return the embed iframe"""
         if self.params:
             from urllib.parse import urlencode
             params = "?" + urlencode(self.params)
         else:
             params = ""
         return self.iframe.format(
             src=self.src,
             width=self.width,
             height=self.height,
             params=params,
             extras=" ".join(self.extras),
         )
 
 
 class YouTubeVideo(IFrame):
     """Class for embedding a YouTube Video in an IPython session, based on its video id.
 
     e.g. to embed the video from https://www.youtube.com/watch?v=foo , you would
     do::
 
         vid = YouTubeVideo("foo")
         display(vid)
 
     To start from 30 seconds::
 
         vid = YouTubeVideo("abc", start=30)
         display(vid)
 
     To calculate seconds from time as hours, minutes, seconds use
     :class:`datetime.timedelta`::
 
         start=int(timedelta(hours=1, minutes=46, seconds=40).total_seconds())
 
     Other parameters can be provided as documented at
     https://developers.google.com/youtube/player_parameters#Parameters
     
     When converting the notebook using nbconvert, a jpeg representation of the video
     will be inserted in the document.
     """
 
     def __init__(self, id, width=400, height=300, allow_autoplay=False, **kwargs):
         self.id=id
         src = "https://www.youtube.com/embed/{0}".format(id)
         if allow_autoplay:
             extras = list(kwargs.get("extras", [])) + ['allow="autoplay"']
             kwargs.update(autoplay=1, extras=extras)
         super(YouTubeVideo, self).__init__(src, width, height, **kwargs)
 
     def _repr_jpeg_(self):
         # Deferred import
         from urllib.request import urlopen
 
         try:
             return urlopen("https://img.youtube.com/vi/{id}/hqdefault.jpg".format(id=self.id)).read()
         except IOError:
             return None
 
 class VimeoVideo(IFrame):
     """
     Class for embedding a Vimeo video in an IPython session, based on its video id.
     """
 
     def __init__(self, id, width=400, height=300, **kwargs):
         src="https://player.vimeo.com/video/{0}".format(id)
         super(VimeoVideo, self).__init__(src, width, height, **kwargs)
 
 class ScribdDocument(IFrame):
     """
     Class for embedding a Scribd document in an IPython session
 
     Use the start_page params to specify a starting point in the document
     Use the view_mode params to specify display type one off scroll | slideshow | book
 
     e.g to Display Wes' foundational paper about PANDAS in book mode from page 3
 
     ScribdDocument(71048089, width=800, height=400, start_page=3, view_mode="book")
     """
 
     def __init__(self, id, width=400, height=300, **kwargs):
         src="https://www.scribd.com/embeds/{0}/content".format(id)
         super(ScribdDocument, self).__init__(src, width, height, **kwargs)
 
 class FileLink(object):
     """Class for embedding a local file link in an IPython session, based on path
 
     e.g. to embed a link that was generated in the IPython notebook as my/data.txt
 
     you would do::
 
         local_file = FileLink("my/data.txt")
         display(local_file)
 
     or in the HTML notebook, just::
 
         FileLink("my/data.txt")
     """
 
     html_link_str = "<a href='%s' target='_blank'>%s</a>"
 
     def __init__(self,
                  path,
                  url_prefix='',
                  result_html_prefix='',
                  result_html_suffix='<br>'):
         """
         Parameters
         ----------
         path : str
             path to the file or directory that should be formatted
         url_prefix : str
             prefix to be prepended to all files to form a working link [default:
             '']
         result_html_prefix : str
             text to append to beginning to link [default: '']
         result_html_suffix : str
             text to append at the end of link [default: '<br>']
         """
         if isdir(path):
             raise ValueError("Cannot display a directory using FileLink. "
               "Use FileLinks to display '%s'." % path)
         self.path = fsdecode(path)
         self.url_prefix = url_prefix
         self.result_html_prefix = result_html_prefix
         self.result_html_suffix = result_html_suffix
 
     def _format_path(self):
         fp = ''.join([self.url_prefix, html_escape(self.path)])
         return ''.join([self.result_html_prefix,
                         self.html_link_str % \
                             (fp, html_escape(self.path, quote=False)),
                         self.result_html_suffix])
 
     def _repr_html_(self):
         """return html link to file
         """
         if not exists(self.path):
             return ("Path (<tt>%s</tt>) doesn't exist. "
                     "It may still be in the process of "
                     "being generated, or you may have the "
                     "incorrect path." % self.path)
 
         return self._format_path()
 
     def __repr__(self):
         """return absolute path to file
         """
         return abspath(self.path)
 
 class FileLinks(FileLink):
     """Class for embedding local file links in an IPython session, based on path
 
     e.g. to embed links to files that were generated in the IPython notebook
     under ``my/data``, you would do::
 
         local_files = FileLinks("my/data")
         display(local_files)
 
     or in the HTML notebook, just::
 
         FileLinks("my/data")
     """
     def __init__(self,
                  path,
                  url_prefix='',
                  included_suffixes=None,
                  result_html_prefix='',
                  result_html_suffix='<br>',
                  notebook_display_formatter=None,
                  terminal_display_formatter=None,
                  recursive=True):
         """
         See :class:`FileLink` for the ``path``, ``url_prefix``,
         ``result_html_prefix`` and ``result_html_suffix`` parameters.
 
         included_suffixes : list
           Filename suffixes to include when formatting output [default: include
           all files]
 
         notebook_display_formatter : function
           Used to format links for display in the notebook. See discussion of
           formatter functions below.
 
         terminal_display_formatter : function
           Used to format links for display in the terminal. See discussion of
           formatter functions below.
 
         Formatter functions must be of the form::
 
             f(dirname, fnames, included_suffixes)
 
         dirname : str
           The name of a directory
         fnames : list
           The files in that directory
         included_suffixes : list
           The file suffixes that should be included in the output (passing None
           meansto include all suffixes in the output in the built-in formatters)
         recursive : boolean
           Whether to recurse into subdirectories. Default is True.
 
         The function should return a list of lines that will be printed in the
         notebook (if passing notebook_display_formatter) or the terminal (if
         passing terminal_display_formatter). This function is iterated over for
         each directory in self.path. Default formatters are in place, can be
         passed here to support alternative formatting.
 
         """
         if isfile(path):
             raise ValueError("Cannot display a file using FileLinks. "
               "Use FileLink to display '%s'." % path)
         self.included_suffixes = included_suffixes
         # remove trailing slashes for more consistent output formatting
         path = path.rstrip('/')
 
         self.path = path
         self.url_prefix = url_prefix
         self.result_html_prefix = result_html_prefix
         self.result_html_suffix = result_html_suffix
 
         self.notebook_display_formatter = \
              notebook_display_formatter or self._get_notebook_display_formatter()
         self.terminal_display_formatter = \
              terminal_display_formatter or self._get_terminal_display_formatter()
 
         self.recursive = recursive
 
     def _get_display_formatter(
         self, dirname_output_format, fname_output_format, fp_format, fp_cleaner=None
     ):
         """generate built-in formatter function
 
         this is used to define both the notebook and terminal built-in
          formatters as they only differ by some wrapper text for each entry
 
         dirname_output_format: string to use for formatting directory
          names, dirname will be substituted for a single "%s" which
          must appear in this string
         fname_output_format: string to use for formatting file names,
          if a single "%s" appears in the string, fname will be substituted
          if two "%s" appear in the string, the path to fname will be
           substituted for the first and fname will be substituted for the
           second
         fp_format: string to use for formatting filepaths, must contain
          exactly two "%s" and the dirname will be substituted for the first
          and fname will be substituted for the second
         """
         def f(dirname, fnames, included_suffixes=None):
             result = []
             # begin by figuring out which filenames, if any,
             # are going to be displayed
             display_fnames = []
             for fname in fnames:
                 if (isfile(join(dirname,fname)) and
                        (included_suffixes is None or
                         splitext(fname)[1] in included_suffixes)):
                       display_fnames.append(fname)
 
             if len(display_fnames) == 0:
                 # if there are no filenames to display, don't print anything
                 # (not even the directory name)
                 pass
             else:
                 # otherwise print the formatted directory name followed by
                 # the formatted filenames
                 dirname_output_line = dirname_output_format % dirname
                 result.append(dirname_output_line)
                 for fname in display_fnames:
                     fp = fp_format % (dirname,fname)
                     if fp_cleaner is not None:
                         fp = fp_cleaner(fp)
                     try:
                         # output can include both a filepath and a filename...
                         fname_output_line = fname_output_format % (fp, fname)
                     except TypeError:
                         # ... or just a single filepath
                         fname_output_line = fname_output_format % fname
                     result.append(fname_output_line)
             return result
         return f
 
     def _get_notebook_display_formatter(self,
                                         spacer="&nbsp;&nbsp;"):
         """ generate function to use for notebook formatting
         """
         dirname_output_format = \
          self.result_html_prefix + "%s/" + self.result_html_suffix
         fname_output_format = \
          self.result_html_prefix + spacer + self.html_link_str + self.result_html_suffix
         fp_format = self.url_prefix + '%s/%s'
         if sep == "\\":
             # Working on a platform where the path separator is "\", so
             # must convert these to "/" for generating a URI
             def fp_cleaner(fp):
                 # Replace all occurrences of backslash ("\") with a forward
                 # slash ("/") - this is necessary on windows when a path is
                 # provided as input, but we must link to a URI
                 return fp.replace('\\','/')
         else:
             fp_cleaner = None
 
         return self._get_display_formatter(dirname_output_format,
                                            fname_output_format,
                                            fp_format,
                                            fp_cleaner)
 
     def _get_terminal_display_formatter(self,
                                         spacer="  "):
         """ generate function to use for terminal formatting
         """
         dirname_output_format = "%s/"
         fname_output_format = spacer + "%s"
         fp_format = '%s/%s'
 
         return self._get_display_formatter(dirname_output_format,
                                            fname_output_format,
                                            fp_format)
 
     def _format_path(self):
         result_lines = []
         if self.recursive:
             walked_dir = list(walk(self.path))
         else:
             walked_dir = [next(walk(self.path))]
         walked_dir.sort()
         for dirname, subdirs, fnames in walked_dir:
             result_lines += self.notebook_display_formatter(dirname, fnames, self.included_suffixes)
         return '\n'.join(result_lines)
 
     def __repr__(self):
         """return newline-separated absolute paths
         """
         result_lines = []
         if self.recursive:
             walked_dir = list(walk(self.path))
         else:
             walked_dir = [next(walk(self.path))]
         walked_dir.sort()
         for dirname, subdirs, fnames in walked_dir:
             result_lines += self.terminal_display_formatter(dirname, fnames, self.included_suffixes)
         return '\n'.join(result_lines)
 
 
 class Code(TextDisplayObject):
     """Display syntax-highlighted source code.
 
     This uses Pygments to highlight the code for HTML and Latex output.
 
     Parameters
     ----------
     data : str
         The code as a string
     url : str
         A URL to fetch the code from
     filename : str
         A local filename to load the code from
     language : str
         The short name of a Pygments lexer to use for highlighting.
         If not specified, it will guess the lexer based on the filename
         or the code. Available lexers: http://pygments.org/docs/lexers/
     """
     def __init__(self, data=None, url=None, filename=None, language=None):
         self.language = language
         super().__init__(data=data, url=url, filename=filename)
 
     def _get_lexer(self):
         if self.language:
             from pygments.lexers import get_lexer_by_name
             return get_lexer_by_name(self.language)
         elif self.filename:
             from pygments.lexers import get_lexer_for_filename
             return get_lexer_for_filename(self.filename)
         else:
             from pygments.lexers import guess_lexer
             return guess_lexer(self.data)
 
     def __repr__(self):
         return self.data
 
     def _repr_html_(self):
         from pygments import highlight
         from pygments.formatters import HtmlFormatter
         fmt = HtmlFormatter()
         style = '<style>{}</style>'.format(fmt.get_style_defs('.output_html'))
         return style + highlight(self.data, self._get_lexer(), fmt)
 
     def _repr_latex_(self):
         from pygments import highlight
         from pygments.formatters import LatexFormatter
         return highlight(self.data, self._get_lexer(), LatexFormatter())

IPython/utils/tz.py

@@ -1,46 +1,48 b''
 # encoding: utf-8
 """
 Timezone utilities
 
 Just UTC-awareness right now
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2013 The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from datetime import tzinfo, timedelta, datetime
 
 #-----------------------------------------------------------------------------
 # Code
 #-----------------------------------------------------------------------------
 # constant for zero offset
 ZERO = timedelta(0)
 
 class tzUTC(tzinfo):
     """tzinfo object for UTC (zero offset)"""
 
     def utcoffset(self, d):
         return ZERO
 
     def dst(self, d):
         return ZERO
 
-UTC = tzUTC()
+
+UTC = tzUTC()  # type: ignore[abstract]
+
 
 def utc_aware(unaware):
     """decorator for adding UTC tzinfo to datetime's utcfoo methods"""
     def utc_method(*args, **kwargs):
         dt = unaware(*args, **kwargs)
         return dt.replace(tzinfo=UTC)
     return utc_method
 
 utcfromtimestamp = utc_aware(datetime.utcfromtimestamp)
 utcnow = utc_aware(datetime.utcnow)

pyproject.toml

@@ -1,3 +1,32 b''
 [build-system]
 requires = ["setuptools >= 51.0.0"]
 build-backend = "setuptools.build_meta"
+[tool.mypy]
+python_version = 3.8
+ignore_missing_imports = true
+follow_imports = 'silent'
+exclude = [
+   'test_\.+\.py',
+   'IPython.utils.tests.test_wildcard',
+   'testing',
+   'tests',
+   'PyColorize.py',
+   '_process_win32_controller.py',
+   'IPython/core/application.py',
+   'IPython/core/completerlib.py',
+   'IPython/core/displaypub.py',
+   'IPython/core/historyapp.py',
+   #'IPython/core/interactiveshell.py',
+   'IPython/core/magic.py',
+   'IPython/core/profileapp.py',
+   'IPython/core/ultratb.py',
+   'IPython/lib/deepreload.py',
+   'IPython/lib/pretty.py',
+   'IPython/sphinxext/ipython_directive.py',
+   'IPython/terminal/ipapp.py',
+   'IPython/utils/_process_win32.py',
+   'IPython/utils/path.py',
+   'IPython/utils/timing.py',
+   'IPython/utils/text.py'
+   ]
+