Handle edge case when requesting subclasses.

obj.__subclasses__ does not havethe usual meaning in case obj == type.

Closes  #11607

IPython/core/oinspect.py

@@ -1,1064 +1,1064 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 linecache
 import warnings
 import os
 from textwrap import dedent
 import types
 import io as stdlib_io
 from itertools import zip_longest
 
 # 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 import py3compat
 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.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
 
 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', 'argspec', 'found', 'name'
                ]
 
 
 def object_info(**kw):
     """Make an object info dict with all fields present."""
     infodict = dict(zip_longest(info_fields, [None]))
     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):
     """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)
     encoding = get_encoding(obj)
     return py3compat.cast_unicode(docstr, encoding=encoding)
 
 
 def getsource(obj, oname=''):
     """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(cast_unicode(
                     ''.join(('# ', oname_prefix, attrname)),
                     encoding=encoding))
                 if inspect.isfunction(fn):
                     sources.append(dedent(getsource(fn)))
                 else:
                     # Default str/repr only prints function name,
                     # pretty.pretty prints module name too.
                     sources.append(cast_unicode(
                         '%s%s = %s\n' % (
                             oname_prefix, attrname, pretty(fn)),
                         encoding=encoding))
         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.
             if hasattr(obj, '__class__'):
                 try:
                     src = inspect.getsource(obj.__class__)
                 except TypeError:
                     return None
 
         encoding = get_encoding(obj)
         return cast_unicode(src, encoding=encoding)
 
 
 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))
 
 
 def getargspec(obj):
     """Wrapper around :func:`inspect.getfullargspec` on Python 3, and
     :func:inspect.getargspec` on Python 2.
 
     In addition to functions and methods, this can also handle objects with a
     ``__call__`` attribute.
     """
     if safe_hasattr(obj, '__call__') and not is_simple_callable(obj):
         obj = obj.__call__
 
     return inspect.getfullargspec(obj)
 
 
 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.
     """
     return inspect.formatargspec(argspec['args'], argspec['varargs'],
                                  argspec['varkw'], argspec['defaults'])
 
 @undoc
 def call_tip(oinfo, format_call=True):
     """DEPRECATED. 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):
     """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.
         if hasattr(obj, '__class__'):
             try:
                 fname = inspect.getabsfile(obj.__class__)
             except TypeError:
                 # Can happen for builtins
                 pass
     except:
         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:
         try:
             lineno = inspect.getsourcelines(obj)[1]
         except TypeError:
             # For instances, try the class object like getsource() does
             if hasattr(obj, '__class__'):
                 lineno = inspect.getsourcelines(obj.__class__)[1]
             else:
                 lineno = None
     except:
         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=''):
         """Return the call signature for any callable object.
 
         If any exception is generated, None is returned instead and the
         exception is suppressed."""
         try:
             hdef = _render_signature(signature(obj), oname)
             return cast_unicode(hdef)
         except:
             return None
 
     def __head(self,h):
         """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 _format_fields(self, fields, title_width=0):
         """Formats a list of fields for display.
 
         Parameters
         ----------
         fields : list
           A list of 2-tuples: (field_title, field_content)
         title_width : int
           How many characters to pad titles to. Default to longest title.
         """
         out = []
         header = self.__head
         if title_width == 0:
             title_width = max(len(title) + 2 for title, _ in fields)
         for title, content in fields:
             if len(content.splitlines()) > 1:
                 title = header(title + ':') + '\n'
             else:
                 title = header((title + ':').ljust(title_width))
             out.append(cast_unicode(title) + cast_unicode(content))
         return "\n".join(out)
 
     def _mime_format(self, text, formatter=None):
         """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.
 
         """
         text = cast_unicode(text)
         defaults = {
             'text/plain': text,
             'text/html': '<pre>' + 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': '<pre>' + formatted + '</pre>'
                 }
 
             else:
                 return dict(defaults, **formatted)
 
 
     def format_mime(self, bundle):
 
         text_plain = bundle['text/plain']
 
         text = ''
         heads, bodies = list(zip(*text_plain))
         _len = max(len(h) for h in heads)
 
         for head, body in zip(heads, bodies):
             body = body.strip('\n')
             delim = '\n' if '\n' in body else ' '
             text += self.__head(head+':') + (_len - len(head))*' ' +delim + body +'\n'
 
         bundle['text/plain'] = text
         return bundle
 
     def _get_info(self, obj, oname='', formatter=None, info=None, detail_level=0):
         """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.
         """
 
         info = self._info(obj, oname=oname, info=info, detail_level=detail_level)
 
         _mime = {
             'text/plain': [],
             'text/html': '',
         }
 
         def append_field(bundle, title, key, formatter=None):
             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'] += '<h1>' + title + '</h1>\n' + formatted_field['text/html'] + '\n'
 
         def code_formatter(text):
             return {
                 'text/plain': self.format(text),
                 'text/html': pylight(text)
             }
 
         if info['isalias']:
             append_field(_mime, 'Repr', 'string_form')
 
         elif info['ismagic']:
             if detail_level > 0:
                 append_field(_mime, 'Source', 'source', code_formatter)
             else:
                 append_field(_mime, 'Docstring', 'docstring', formatter)
             append_field(_mime, 'File', 'file')
 
         elif info['isclass'] or is_simple_callable(obj):
             # Functions, methods, classes
             append_field(_mime, 'Signature', 'definition', code_formatter)
             append_field(_mime, 'Init signature', 'init_definition', code_formatter)
             append_field(_mime, 'Docstring', 'docstring', formatter)
             if detail_level > 0 and info['source']:
                 append_field(_mime, 'Source', 'source', code_formatter)
             else:
                 append_field(_mime, 'Init docstring', 'init_docstring', formatter)
 
             append_field(_mime, 'File', 'file')
             append_field(_mime, 'Type', 'type_name')
             append_field(_mime, 'Subclasses', 'subclasses')
 
         else:
             # General Python objects
             append_field(_mime, 'Signature', 'definition', code_formatter)
             append_field(_mime, 'Call signature', 'call_def', code_formatter)
             append_field(_mime, 'Type', 'type_name')
             append_field(_mime, 'String form', 'string_form')
 
             # Namespace
             if info['namespace'] != 'Interactive':
                 append_field(_mime, 'Namespace', 'namespace')
 
             append_field(_mime, 'Length', 'length')
             append_field(_mime, 'File', 'file')
 
             # Source or docstring, depending on detail level and whether
             # source found.
             if detail_level > 0 and info['source']:
                 append_field(_mime, 'Source', 'source', code_formatter)
             else:
                 append_field(_mime, 'Docstring', 'docstring', formatter)
 
             append_field(_mime, 'Class docstring', 'class_docstring', formatter)
             append_field(_mime, 'Init docstring', 'init_docstring', formatter)
             append_field(_mime, 'Call docstring', 'call_docstring', formatter)
 
 
         return self.format_mime(_mime)
 
     def pinfo(self, obj, oname='', formatter=None, info=None, detail_level=0, enable_html_pager=True):
         """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.
         """
         info = self._get_info(obj, oname, formatter, info, detail_level)
         if not enable_html_pager:
             del info['text/html']
         page.page(info)
 
     def info(self, obj, oname='', formatter=None, info=None, detail_level=0):
         """DEPRECATED. Compute a dict with detailed information about an object.
         """
         if formatter is not None:
             warnings.warn('The `formatter` keyword argument to `Inspector.info`'
                      'is deprecated as of IPython 5.0 and will have no effects.',
                       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`.
         """
 
         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 = '<no docstring>'
 
         # 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 obj.__subclasses__()]
+            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
 
         # Compute the object's argspec as a callable.  The key is to decide
         # whether to pull it from the object itself, from its __init__ or
         # from its __call__ method.
 
         if inspect.isclass(obj):
             # Old-style classes need not have an __init__
             callable_obj = getattr(obj, "__init__", None)
         elif callable(obj):
             callable_obj = obj
         else:
             callable_obj = None
 
         if callable_obj is not None:
             try:
                 argspec = getargspec(callable_obj)
             except Exception:
                 # For extensions/builtins we can't retrieve the argspec
                 pass
             else:
                 # named tuples' _asdict() method returns an OrderedDict, but we
                 # we want a normal
                 out['argspec'] = argspec_dict = dict(argspec._asdict())
                 # We called this varkw before argspec became a named tuple.
                 # With getfullargspec it's also called varkw.
                 if 'varkw' not in argspec_dict:
                     argspec_dict['varkw'] = argspec_dict.pop('keywords')
 
         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):
         """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.
         """
         #print 'ps pattern:<%r>' % pattern # dbg
 
         # defaults
         type_pattern = 'all'
         filter = ''
 
         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):
     """
     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:
             pos_only = True
         elif pos_only:
             result.append('/')
             pos_only = False
 
         if param.kind == inspect._VAR_POSITIONAL:
             kw_only = False
         elif param.kind == inspect._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_oinspect.py

@@ -1,474 +1,480 b''
 """Tests for the object inspection functionality.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 
 from inspect import signature, Signature, Parameter
 import os
 import re
 import sys
 
 import nose.tools as nt
 
 from .. import oinspect
 from IPython.core.magic import (Magics, magics_class, line_magic,
                                 cell_magic, line_cell_magic,
                                 register_line_magic, register_cell_magic,
                                 register_line_cell_magic)
 from decorator import decorator
 from IPython import get_ipython
 from IPython.testing.tools import AssertPrints, AssertNotPrints
 from IPython.utils.path import compress_user
 
 
 #-----------------------------------------------------------------------------
 # Globals and constants
 #-----------------------------------------------------------------------------
 
 inspector = oinspect.Inspector()
 ip = get_ipython()
 
 #-----------------------------------------------------------------------------
 # Local utilities
 #-----------------------------------------------------------------------------
 
 # WARNING: since this test checks the line number where a function is
 # defined, if any code is inserted above, the following line will need to be
 # updated.  Do NOT insert any whitespace between the next line and the function
 # definition below.
 THIS_LINE_NUMBER = 41  # Put here the actual number of this line
 
 from unittest import TestCase
 
 class Test(TestCase):
 
     def test_find_source_lines(self):
         self.assertEqual(oinspect.find_source_lines(Test.test_find_source_lines),
                     THIS_LINE_NUMBER+6)
 
 
 # A couple of utilities to ensure these tests work the same from a source or a
 # binary install
 def pyfile(fname):
     return os.path.normcase(re.sub('.py[co]$', '.py', fname))
 
 
 def match_pyfiles(f1, f2):
     nt.assert_equal(pyfile(f1), pyfile(f2))
 
 
 def test_find_file():
     match_pyfiles(oinspect.find_file(test_find_file), os.path.abspath(__file__))
 
 
 def test_find_file_decorated1():
 
     @decorator
     def noop1(f):
         def wrapper(*a, **kw):
             return f(*a, **kw)
         return wrapper
 
     @noop1
     def f(x):
         "My docstring"
     
     match_pyfiles(oinspect.find_file(f), os.path.abspath(__file__))
     nt.assert_equal(f.__doc__, "My docstring")
 
 
 def test_find_file_decorated2():
 
     @decorator
     def noop2(f, *a, **kw):
         return f(*a, **kw)
 
     @noop2
     @noop2
     @noop2
     def f(x):
         "My docstring 2"
     
     match_pyfiles(oinspect.find_file(f), os.path.abspath(__file__))
     nt.assert_equal(f.__doc__, "My docstring 2")
     
 
 def test_find_file_magic():
     run = ip.find_line_magic('run')
     nt.assert_not_equal(oinspect.find_file(run), None)
 
 
 # A few generic objects we can then inspect in the tests below
 
 class Call(object):
     """This is the class docstring."""
 
     def __init__(self, x, y=1):
         """This is the constructor docstring."""
 
     def __call__(self, *a, **kw):
         """This is the call docstring."""
 
     def method(self, x, z=2):
         """Some method's docstring"""
 
 class HasSignature(object):
     """This is the class docstring."""
     __signature__ = Signature([Parameter('test', Parameter.POSITIONAL_OR_KEYWORD)])
 
     def __init__(self, *args):
         """This is the init docstring"""
 
 
 class SimpleClass(object):
     def method(self, x, z=2):
         """Some method's docstring"""
 
 
 class OldStyle:
     """An old-style class for testing."""
     pass
 
 
 def f(x, y=2, *a, **kw):
     """A simple function."""
 
 
 def g(y, z=3, *a, **kw):
     pass  # no docstring
 
 
 @register_line_magic
 def lmagic(line):
     "A line magic"
 
 
 @register_cell_magic
 def cmagic(line, cell):
     "A cell magic"
 
 
 @register_line_cell_magic
 def lcmagic(line, cell=None):
     "A line/cell magic"
 
 
 @magics_class
 class SimpleMagics(Magics):
     @line_magic
     def Clmagic(self, cline):
         "A class-based line magic"
         
     @cell_magic
     def Ccmagic(self, cline, ccell):
         "A class-based cell magic"
         
     @line_cell_magic
     def Clcmagic(self, cline, ccell=None):
         "A class-based line/cell magic"
 
 
 class Awkward(object):
     def __getattr__(self, name):
         raise Exception(name)
 
 class NoBoolCall:
     """
     callable with `__bool__` raising should still be inspect-able.
     """
 
     def __call__(self):
         """does nothing"""
         pass
 
     def __bool__(self):
         """just raise NotImplemented"""
         raise NotImplementedError('Must be implemented')
 
 
 class SerialLiar(object):
     """Attribute accesses always get another copy of the same class.
 
     unittest.mock.call does something similar, but it's not ideal for testing
     as the failure mode is to eat all your RAM. This gives up after 10k levels.
     """
     def __init__(self, max_fibbing_twig, lies_told=0):
         if lies_told > 10000:
             raise RuntimeError('Nose too long, honesty is the best policy')
         self.max_fibbing_twig = max_fibbing_twig
         self.lies_told = lies_told
         max_fibbing_twig[0] = max(max_fibbing_twig[0], lies_told)
 
     def __getattr__(self, item):
         return SerialLiar(self.max_fibbing_twig, self.lies_told + 1)
 
 #-----------------------------------------------------------------------------
 # Tests
 #-----------------------------------------------------------------------------
 
 def test_info():
     "Check that Inspector.info fills out various fields as expected."
     i = inspector.info(Call, oname='Call')
     nt.assert_equal(i['type_name'], 'type')
     expted_class = str(type(type))  # <class 'type'> (Python 3) or <type 'type'>
     nt.assert_equal(i['base_class'], expted_class)
     nt.assert_regex(i['string_form'], "<class 'IPython.core.tests.test_oinspect.Call'( at 0x[0-9a-f]{1,9})?>")
     fname = __file__
     if fname.endswith(".pyc"):
         fname = fname[:-1]
     # case-insensitive comparison needed on some filesystems
     # e.g. Windows:
     nt.assert_equal(i['file'].lower(), compress_user(fname).lower())
     nt.assert_equal(i['definition'], None)
     nt.assert_equal(i['docstring'], Call.__doc__)
     nt.assert_equal(i['source'], None)
     nt.assert_true(i['isclass'])
     nt.assert_equal(i['init_definition'], "Call(x, y=1)")
     nt.assert_equal(i['init_docstring'], Call.__init__.__doc__)
 
     i = inspector.info(Call, detail_level=1)
     nt.assert_not_equal(i['source'], None)
     nt.assert_equal(i['docstring'], None)
 
     c = Call(1)
     c.__doc__ = "Modified instance docstring"
     i = inspector.info(c)
     nt.assert_equal(i['type_name'], 'Call')
     nt.assert_equal(i['docstring'], "Modified instance docstring")
     nt.assert_equal(i['class_docstring'], Call.__doc__)
     nt.assert_equal(i['init_docstring'], Call.__init__.__doc__)
     nt.assert_equal(i['call_docstring'], Call.__call__.__doc__)
 
 def test_class_signature():
     info = inspector.info(HasSignature, 'HasSignature')
     nt.assert_equal(info['init_definition'], "HasSignature(test)")
     nt.assert_equal(info['init_docstring'], HasSignature.__init__.__doc__)
 
 def test_info_awkward():
     # Just test that this doesn't throw an error.
     inspector.info(Awkward())
 
 def test_bool_raise():
     inspector.info(NoBoolCall())
 
 def test_info_serialliar():
     fib_tracker = [0]
     inspector.info(SerialLiar(fib_tracker))
 
     # Nested attribute access should be cut off at 100 levels deep to avoid
     # infinite loops: https://github.com/ipython/ipython/issues/9122
     nt.assert_less(fib_tracker[0], 9000)
 
 def test_calldef_none():
     # We should ignore __call__ for all of these.
     for obj in [f, SimpleClass().method, any, str.upper]:
         print(obj)
         i = inspector.info(obj)
         nt.assert_is(i['call_def'], None)
 
 def f_kwarg(pos, *, kwonly):
     pass
 
 def test_definition_kwonlyargs():
     i = inspector.info(f_kwarg, oname='f_kwarg')  # analysis:ignore
     nt.assert_equal(i['definition'], "f_kwarg(pos, *, kwonly)")
 
 def test_getdoc():
     class A(object):
         """standard docstring"""
         pass
 
     class B(object):
         """standard docstring"""
         def getdoc(self):
             return "custom docstring"
     
     class C(object):
         """standard docstring"""
         def getdoc(self):
             return None
     
     a = A()
     b = B()
     c = C()
     
     nt.assert_equal(oinspect.getdoc(a), "standard docstring")
     nt.assert_equal(oinspect.getdoc(b), "custom docstring")
     nt.assert_equal(oinspect.getdoc(c), "standard docstring")
 
 
 def test_empty_property_has_no_source():
     i = inspector.info(property(), detail_level=1)
     nt.assert_is(i['source'], None)
 
 
 def test_property_sources():
     import posixpath 
     # A simple adder whose source and signature stays
     # the same across Python distributions
     def simple_add(a, b):
         "Adds two numbers"
         return a + b
     
     class A(object):
         @property
         def foo(self):
             return 'bar'
 
         foo = foo.setter(lambda self, v: setattr(self, 'bar', v))
 
         dname = property(posixpath.dirname)
         adder = property(simple_add) 
 
     i = inspector.info(A.foo, detail_level=1)
     nt.assert_in('def foo(self):', i['source'])
     nt.assert_in('lambda self, v:', i['source'])
 
     i = inspector.info(A.dname, detail_level=1)
     nt.assert_in('def dirname(p)', i['source'])
     
     i = inspector.info(A.adder, detail_level=1)
     nt.assert_in('def simple_add(a, b)', i['source'])
 
 
 def test_property_docstring_is_in_info_for_detail_level_0():
     class A(object):
         @property
         def foobar(self):
             """This is `foobar` property."""
             pass
 
     ip.user_ns['a_obj'] = A()
     nt.assert_equal(
         'This is `foobar` property.',
         ip.object_inspect('a_obj.foobar', detail_level=0)['docstring'])
 
     ip.user_ns['a_cls'] = A
     nt.assert_equal(
         'This is `foobar` property.',
         ip.object_inspect('a_cls.foobar', detail_level=0)['docstring'])
 
 
 def test_pdef():
     # See gh-1914
     def foo(): pass
     inspector.pdef(foo, 'foo')
 
 
 def test_pinfo_nonascii():
     # See gh-1177
     from . import nonascii2
     ip.user_ns['nonascii2'] = nonascii2
     ip._inspect('pinfo', 'nonascii2', detail_level=1)
 
+def test_pinfo_type():
+    """
+    type can fail in various edge case, for example `type.__subclass__()`
+    """
+    ip._inspect('pinfo', 'type')
+
 
 def test_pinfo_docstring_no_source():
     """Docstring should be included with detail_level=1 if there is no source"""
     with AssertPrints('Docstring:'):
         ip._inspect('pinfo', 'str.format', detail_level=0)
     with AssertPrints('Docstring:'):
         ip._inspect('pinfo', 'str.format', detail_level=1)
 
 
 def test_pinfo_no_docstring_if_source():
     """Docstring should not be included with detail_level=1 if source is found"""
     def foo():
         """foo has a docstring"""
 
     ip.user_ns['foo'] = foo
 
     with AssertPrints('Docstring:'):
         ip._inspect('pinfo', 'foo', detail_level=0)
     with AssertPrints('Source:'):
         ip._inspect('pinfo', 'foo', detail_level=1)
     with AssertNotPrints('Docstring:'):
         ip._inspect('pinfo', 'foo', detail_level=1)
 
 
 def test_pinfo_docstring_if_detail_and_no_source():
     """ Docstring should be displayed if source info not available """
     obj_def = '''class Foo(object):
                   """ This is a docstring for Foo """
                   def bar(self):
                       """ This is a docstring for Foo.bar """
                       pass
               ''' 
     
     ip.run_cell(obj_def)
     ip.run_cell('foo = Foo()')
     
     with AssertNotPrints("Source:"):
         with AssertPrints('Docstring:'):
             ip._inspect('pinfo', 'foo', detail_level=0)
         with AssertPrints('Docstring:'):
             ip._inspect('pinfo', 'foo', detail_level=1)
         with AssertPrints('Docstring:'):
             ip._inspect('pinfo', 'foo.bar', detail_level=0)
 
     with AssertNotPrints('Docstring:'):
         with AssertPrints('Source:'):
             ip._inspect('pinfo', 'foo.bar', detail_level=1)
 
 
 def test_pinfo_magic():
     with AssertPrints('Docstring:'):
         ip._inspect('pinfo', 'lsmagic', detail_level=0)
 
     with AssertPrints('Source:'):
         ip._inspect('pinfo', 'lsmagic', detail_level=1)
 
 
 def test_init_colors():
     # ensure colors are not present in signature info
     info = inspector.info(HasSignature)
     init_def = info['init_definition']
     nt.assert_not_in('[0m', init_def)
 
 
 def test_builtin_init():
     info = inspector.info(list)
     init_def = info['init_definition']
     nt.assert_is_not_none(init_def)
 
 
 def test_render_signature_short():
     def short_fun(a=1): pass
     sig = oinspect._render_signature(
         signature(short_fun),
         short_fun.__name__,
     )
     nt.assert_equal(sig, 'short_fun(a=1)')
 
 
 def test_render_signature_long():
     from typing import Optional
 
     def long_function(
         a_really_long_parameter: int,
         and_another_long_one: bool = False,
         let_us_make_sure_this_is_looong: Optional[str] = None,
     ) -> bool: pass
 
     sig = oinspect._render_signature(
         signature(long_function),
         long_function.__name__,
     )
     nt.assert_in(sig, [
         # Python >=3.7
         '''\
 long_function(
     a_really_long_parameter: int,
     and_another_long_one: bool = False,
     let_us_make_sure_this_is_looong: Union[str, NoneType] = None,
 ) -> bool\
 ''',  # Python <=3.6
         '''\
 long_function(
     a_really_long_parameter:int,
     and_another_long_one:bool=False,
     let_us_make_sure_this_is_looong:Union[str, NoneType]=None,
 ) -> bool\
 ''',
     ])