Always display last frame when show tracebacks with hidden frames.

Partial toward  #12565,

This is slightly more complicated when we start the debugger as we would
need to track which frame we started on.

IPython/core/debugger.py

@@ -1,809 +1,813 b''
 # -*- coding: utf-8 -*-
 """
 Pdb debugger class.
 
 Modified from the standard pdb.Pdb class to avoid including readline, so that
 the command line completion of other programs which include this isn't
 damaged.
 
 In the future, this class will be expanded with improvements over the standard
 pdb.
 
 The code in this file is mainly lifted out of cmd.py in Python 2.2, with minor
 changes. Licensing should therefore be under the standard Python terms.  For
 details on the PSF (Python Software Foundation) standard license, see:
 
 https://docs.python.org/2/license.html
 """
 
 #*****************************************************************************
 #
 #       This file is licensed under the PSF license.
 #
 #       Copyright (C) 2001 Python Software Foundation, www.python.org
 #       Copyright (C) 2005-2006 Fernando Perez. <[e-mail]>
 #
 #
 #*****************************************************************************
 
 import bdb
 import functools
 import inspect
 import linecache
 import sys
 import warnings
 import re
 
 from IPython import get_ipython
 from IPython.utils import PyColorize
 from IPython.utils import coloransi, py3compat
 from IPython.core.excolors import exception_colors
 from IPython.testing.skipdoctest import skip_doctest
 
 
 prompt = 'ipdb> '
 
 #We have to check this directly from sys.argv, config struct not yet available
 from pdb import Pdb as OldPdb
 
 # Allow the set_trace code to operate outside of an ipython instance, even if
 # it does so with some limitations.  The rest of this support is implemented in
 # the Tracer constructor.
 
 def make_arrow(pad):
     """generate the leading arrow in front of traceback or debugger"""
     if pad >= 2:
         return '-'*(pad-2) + '> '
     elif pad == 1:
         return '>'
     return ''
 
 
 def BdbQuit_excepthook(et, ev, tb, excepthook=None):
     """Exception hook which handles `BdbQuit` exceptions.
 
     All other exceptions are processed using the `excepthook`
     parameter.
     """
     warnings.warn("`BdbQuit_excepthook` is deprecated since version 5.1",
                   DeprecationWarning, stacklevel=2)
     if et==bdb.BdbQuit:
         print('Exiting Debugger.')
     elif excepthook is not None:
         excepthook(et, ev, tb)
     else:
         # Backwards compatibility. Raise deprecation warning?
         BdbQuit_excepthook.excepthook_ori(et,ev,tb)
 
 
 def BdbQuit_IPython_excepthook(self,et,ev,tb,tb_offset=None):
     warnings.warn(
         "`BdbQuit_IPython_excepthook` is deprecated since version 5.1",
         DeprecationWarning, stacklevel=2)
     print('Exiting Debugger.')
 
 
 class Tracer(object):
     """
     DEPRECATED
 
     Class for local debugging, similar to pdb.set_trace.
 
     Instances of this class, when called, behave like pdb.set_trace, but
     providing IPython's enhanced capabilities.
 
     This is implemented as a class which must be initialized in your own code
     and not as a standalone function because we need to detect at runtime
     whether IPython is already active or not.  That detection is done in the
     constructor, ensuring that this code plays nicely with a running IPython,
     while functioning acceptably (though with limitations) if outside of it.
     """
 
     @skip_doctest
     def __init__(self, colors=None):
         """
         DEPRECATED
 
         Create a local debugger instance.
 
         Parameters
         ----------
 
         colors : str, optional
             The name of the color scheme to use, it must be one of IPython's
             valid color schemes.  If not given, the function will default to
             the current IPython scheme when running inside IPython, and to
             'NoColor' otherwise.
 
         Examples
         --------
         ::
 
             from IPython.core.debugger import Tracer; debug_here = Tracer()
 
         Later in your code::
 
             debug_here()  # -> will open up the debugger at that point.
 
         Once the debugger activates, you can use all of its regular commands to
         step through code, set breakpoints, etc.  See the pdb documentation
         from the Python standard library for usage details.
         """
         warnings.warn("`Tracer` is deprecated since version 5.1, directly use "
                       "`IPython.core.debugger.Pdb.set_trace()`",
                       DeprecationWarning, stacklevel=2)
 
         ip = get_ipython()
         if ip is None:
             # Outside of ipython, we set our own exception hook manually
             sys.excepthook = functools.partial(BdbQuit_excepthook,
                                                excepthook=sys.excepthook)
             def_colors = 'NoColor'
         else:
             # In ipython, we use its custom exception handler mechanism
             def_colors = ip.colors
             ip.set_custom_exc((bdb.BdbQuit,), BdbQuit_IPython_excepthook)
 
         if colors is None:
             colors = def_colors
 
         # The stdlib debugger internally uses a modified repr from the `repr`
         # module, that limits the length of printed strings to a hardcoded
         # limit of 30 characters.  That much trimming is too aggressive, let's
         # at least raise that limit to 80 chars, which should be enough for
         # most interactive uses.
         try:
             from reprlib import aRepr
             aRepr.maxstring = 80
         except:
             # This is only a user-facing convenience, so any error we encounter
             # here can be warned about but can be otherwise ignored.  These
             # printouts will tell us about problems if this API changes
             import traceback
             traceback.print_exc()
 
         self.debugger = Pdb(colors)
 
     def __call__(self):
         """Starts an interactive debugger at the point where called.
 
         This is similar to the pdb.set_trace() function from the std lib, but
         using IPython's enhanced debugger."""
 
         self.debugger.set_trace(sys._getframe().f_back)
 
 
 RGX_EXTRA_INDENT = re.compile(r'(?<=\n)\s+')
 
 
 def strip_indentation(multiline_string):
     return RGX_EXTRA_INDENT.sub('', multiline_string)
 
 
 def decorate_fn_with_doc(new_fn, old_fn, additional_text=""):
     """Make new_fn have old_fn's doc string. This is particularly useful
     for the ``do_...`` commands that hook into the help system.
     Adapted from from a comp.lang.python posting
     by Duncan Booth."""
     def wrapper(*args, **kw):
         return new_fn(*args, **kw)
     if old_fn.__doc__:
         wrapper.__doc__ = strip_indentation(old_fn.__doc__) + additional_text
     return wrapper
 
 
 class Pdb(OldPdb):
     """Modified Pdb class, does not load readline.
 
     for a standalone version that uses prompt_toolkit, see
     `IPython.terminal.debugger.TerminalPdb` and
     `IPython.terminal.debugger.set_trace()`
     """
 
     def __init__(self, color_scheme=None, completekey=None,
                  stdin=None, stdout=None, context=5, **kwargs):
         """Create a new IPython debugger.
         
         :param color_scheme: Deprecated, do not use.
         :param completekey: Passed to pdb.Pdb.
         :param stdin: Passed to pdb.Pdb.
         :param stdout: Passed to pdb.Pdb.
         :param context: Number of lines of source code context to show when
             displaying stacktrace information.
         :param kwargs: Passed to pdb.Pdb.
             The possibilities are python version dependent, see the python
             docs for more info.
         """
 
         # Parent constructor:
         try:
             self.context = int(context)
             if self.context <= 0:
                 raise ValueError("Context must be a positive integer")
         except (TypeError, ValueError) as e:
                 raise ValueError("Context must be a positive integer") from e
 
         # `kwargs` ensures full compatibility with stdlib's `pdb.Pdb`.
         OldPdb.__init__(self, completekey, stdin, stdout, **kwargs)
 
         # IPython changes...
         self.shell = get_ipython()
 
         if self.shell is None:
             save_main = sys.modules['__main__']
             # No IPython instance running, we must create one
             from IPython.terminal.interactiveshell import \
                 TerminalInteractiveShell
             self.shell = TerminalInteractiveShell.instance()
             # needed by any code which calls __import__("__main__") after
             # the debugger was entered. See also #9941.
             sys.modules['__main__'] = save_main 
 
         if color_scheme is not None:
             warnings.warn(
                 "The `color_scheme` argument is deprecated since version 5.1",
                 DeprecationWarning, stacklevel=2)
         else:
             color_scheme = self.shell.colors
 
         self.aliases = {}
 
         # Create color table: we copy the default one from the traceback
         # module and add a few attributes needed for debugging
         self.color_scheme_table = exception_colors()
 
         # shorthands
         C = coloransi.TermColors
         cst = self.color_scheme_table
 
         cst['NoColor'].colors.prompt = C.NoColor
         cst['NoColor'].colors.breakpoint_enabled = C.NoColor
         cst['NoColor'].colors.breakpoint_disabled = C.NoColor
 
         cst['Linux'].colors.prompt = C.Green
         cst['Linux'].colors.breakpoint_enabled = C.LightRed
         cst['Linux'].colors.breakpoint_disabled = C.Red
 
         cst['LightBG'].colors.prompt = C.Blue
         cst['LightBG'].colors.breakpoint_enabled = C.LightRed
         cst['LightBG'].colors.breakpoint_disabled = C.Red
 
         cst['Neutral'].colors.prompt = C.Blue
         cst['Neutral'].colors.breakpoint_enabled = C.LightRed
         cst['Neutral'].colors.breakpoint_disabled = C.Red
 
 
         # Add a python parser so we can syntax highlight source while
         # debugging.
         self.parser = PyColorize.Parser(style=color_scheme)
         self.set_colors(color_scheme)
 
         # Set the prompt - the default prompt is '(Pdb)'
         self.prompt = prompt
         self.skip_hidden = True
 
     def set_colors(self, scheme):
         """Shorthand access to the color table scheme selector method."""
         self.color_scheme_table.set_active_scheme(scheme)
         self.parser.style = scheme
 
 
     def hidden_frames(self, stack):
         """
-        Given an index in the stack return wether it should be skipped.
+        Given an index in the stack return whether it should be skipped.
 
         This is used in up/down and where to skip frames.
         """
         # The f_locals dictionary is updated from the actual frame
         # locals whenever the .f_locals accessor is called, so we
         # avoid calling it here to preserve self.curframe_locals.
         # Futhermore, there is no good reason to hide the current frame.
         ip_hide = [
             False if s[0] is self.curframe else s[0].f_locals.get(
                 "__tracebackhide__", False)
             for s in stack]
         ip_start = [i for i, s in enumerate(ip_hide) if s == "__ipython_bottom__"]
         if ip_start:
             ip_hide = [h if i > ip_start[0] else True for (i, h) in enumerate(ip_hide)]
         return ip_hide
 
     def interaction(self, frame, traceback):
         try:
             OldPdb.interaction(self, frame, traceback)
         except KeyboardInterrupt:
             self.stdout.write("\n" + self.shell.get_exception_only())
 
     def new_do_frame(self, arg):
         OldPdb.do_frame(self, arg)
 
     def new_do_quit(self, arg):
 
         if hasattr(self, 'old_all_completions'):
             self.shell.Completer.all_completions=self.old_all_completions
 
         return OldPdb.do_quit(self, arg)
 
     do_q = do_quit = decorate_fn_with_doc(new_do_quit, OldPdb.do_quit)
 
     def new_do_restart(self, arg):
         """Restart command. In the context of ipython this is exactly the same
         thing as 'quit'."""
         self.msg("Restart doesn't make sense here. Using 'quit' instead.")
         return self.do_quit(arg)
 
     def print_stack_trace(self, context=None):
         Colors = self.color_scheme_table.active_colors
         ColorsNormal = Colors.Normal
         if context is None:
             context = self.context
         try:
             context=int(context)
             if context <= 0:
                 raise ValueError("Context must be a positive integer")
         except (TypeError, ValueError) as e:
                 raise ValueError("Context must be a positive integer") from e
         try:
             skipped = 0
             for hidden, frame_lineno in zip(self.hidden_frames(self.stack), self.stack):
                 if hidden and self.skip_hidden:
                     skipped += 1
                     continue
                 if skipped:
                     print(
                         f"{Colors.excName}    [... skipping {skipped} hidden frame(s)]{ColorsNormal}\n"
                     )
                     skipped = 0
                 self.print_stack_entry(frame_lineno, context=context)
             if skipped:
                 print(
                     f"{Colors.excName}    [... skipping {skipped} hidden frame(s)]{ColorsNormal}\n"
                 )
         except KeyboardInterrupt:
             pass
 
     def print_stack_entry(self, frame_lineno, prompt_prefix='\n-> ',
                           context=None):
         if context is None:
             context = self.context
         try:
             context=int(context)
             if context <= 0:
                 raise ValueError("Context must be a positive integer")
         except (TypeError, ValueError) as e:
                 raise ValueError("Context must be a positive integer") from e
         print(self.format_stack_entry(frame_lineno, '', context), file=self.stdout)
 
         # vds: >>
         frame, lineno = frame_lineno
         filename = frame.f_code.co_filename
         self.shell.hooks.synchronize_with_editor(filename, lineno, 0)
         # vds: <<
 
     def format_stack_entry(self, frame_lineno, lprefix=': ', context=None):
         if context is None:
             context = self.context
         try:
             context=int(context)
             if context <= 0:
                 print("Context must be a positive integer", file=self.stdout)
         except (TypeError, ValueError):
                 print("Context must be a positive integer", file=self.stdout)
 
         import reprlib
 
         ret = []
 
         Colors = self.color_scheme_table.active_colors
         ColorsNormal = Colors.Normal
         tpl_link = u'%s%%s%s' % (Colors.filenameEm, ColorsNormal)
         tpl_call = u'%s%%s%s%%s%s' % (Colors.vName, Colors.valEm, ColorsNormal)
         tpl_line = u'%%s%s%%s %s%%s' % (Colors.lineno, ColorsNormal)
         tpl_line_em = u'%%s%s%%s %s%%s%s' % (Colors.linenoEm, Colors.line,
                                             ColorsNormal)
 
         frame, lineno = frame_lineno
 
         return_value = ''
         if '__return__' in frame.f_locals:
             rv = frame.f_locals['__return__']
             #return_value += '->'
             return_value += reprlib.repr(rv) + '\n'
         ret.append(return_value)
 
         #s = filename + '(' + `lineno` + ')'
         filename = self.canonic(frame.f_code.co_filename)
         link = tpl_link % py3compat.cast_unicode(filename)
 
         if frame.f_code.co_name:
             func = frame.f_code.co_name
         else:
             func = "<lambda>"
 
         call = ''
         if func != '?':
             if '__args__' in frame.f_locals:
                 args = reprlib.repr(frame.f_locals['__args__'])
             else:
                 args = '()'
             call = tpl_call % (func, args)
 
         # The level info should be generated in the same format pdb uses, to
         # avoid breaking the pdbtrack functionality of python-mode in *emacs.
         if frame is self.curframe:
             ret.append('> ')
         else:
             ret.append('  ')
         ret.append(u'%s(%s)%s\n' % (link,lineno,call))
 
         start = lineno - 1 - context//2
         lines = linecache.getlines(filename)
         start = min(start, len(lines) - context)
         start = max(start, 0)
         lines = lines[start : start + context]
 
         for i,line in enumerate(lines):
             show_arrow = (start + 1 + i == lineno)
             linetpl = (frame is self.curframe or show_arrow) \
                       and tpl_line_em \
                       or tpl_line
             ret.append(self.__format_line(linetpl, filename,
                                           start + 1 + i, line,
                                           arrow = show_arrow) )
         return ''.join(ret)
 
     def __format_line(self, tpl_line, filename, lineno, line, arrow = False):
         bp_mark = ""
         bp_mark_color = ""
 
         new_line, err = self.parser.format2(line, 'str')
         if not err:
             line = new_line
 
         bp = None
         if lineno in self.get_file_breaks(filename):
             bps = self.get_breaks(filename, lineno)
             bp = bps[-1]
 
         if bp:
             Colors = self.color_scheme_table.active_colors
             bp_mark = str(bp.number)
             bp_mark_color = Colors.breakpoint_enabled
             if not bp.enabled:
                 bp_mark_color = Colors.breakpoint_disabled
 
         numbers_width = 7
         if arrow:
             # This is the line with the error
             pad = numbers_width - len(str(lineno)) - len(bp_mark)
             num = '%s%s' % (make_arrow(pad), str(lineno))
         else:
             num = '%*s' % (numbers_width - len(bp_mark), str(lineno))
 
         return tpl_line % (bp_mark_color + bp_mark, num, line)
 
 
     def print_list_lines(self, filename, first, last):
         """The printing (as opposed to the parsing part of a 'list'
         command."""
         try:
             Colors = self.color_scheme_table.active_colors
             ColorsNormal = Colors.Normal
             tpl_line = '%%s%s%%s %s%%s' % (Colors.lineno, ColorsNormal)
             tpl_line_em = '%%s%s%%s %s%%s%s' % (Colors.linenoEm, Colors.line, ColorsNormal)
             src = []
             if filename == "<string>" and hasattr(self, "_exec_filename"):
                 filename = self._exec_filename
 
             for lineno in range(first, last+1):
                 line = linecache.getline(filename, lineno)
                 if not line:
                     break
 
                 if lineno == self.curframe.f_lineno:
                     line = self.__format_line(tpl_line_em, filename, lineno, line, arrow = True)
                 else:
                     line = self.__format_line(tpl_line, filename, lineno, line, arrow = False)
 
                 src.append(line)
                 self.lineno = lineno
 
             print(''.join(src), file=self.stdout)
 
         except KeyboardInterrupt:
             pass
 
     def do_skip_hidden(self, arg):
         """
         Change whether or not we should skip frames with the
         __tracebackhide__ attribute.
         """
         if arg.strip().lower() in ("true", "yes"):
             self.skip_hidden = True
         elif arg.strip().lower() in ("false", "no"):
             self.skip_hidden = False
 
     def do_list(self, arg):
         """Print lines of code from the current stack frame
         """
         self.lastcmd = 'list'
         last = None
         if arg:
             try:
                 x = eval(arg, {}, {})
                 if type(x) == type(()):
                     first, last = x
                     first = int(first)
                     last = int(last)
                     if last < first:
                         # Assume it's a count
                         last = first + last
                 else:
                     first = max(1, int(x) - 5)
             except:
                 print('*** Error in argument:', repr(arg), file=self.stdout)
                 return
         elif self.lineno is None:
             first = max(1, self.curframe.f_lineno - 5)
         else:
             first = self.lineno + 1
         if last is None:
             last = first + 10
         self.print_list_lines(self.curframe.f_code.co_filename, first, last)
 
         # vds: >>
         lineno = first
         filename = self.curframe.f_code.co_filename
         self.shell.hooks.synchronize_with_editor(filename, lineno, 0)
         # vds: <<
 
     do_l = do_list
 
     def getsourcelines(self, obj):
         lines, lineno = inspect.findsource(obj)
         if inspect.isframe(obj) and obj.f_globals is obj.f_locals:
             # must be a module frame: do not try to cut a block out of it
             return lines, 1
         elif inspect.ismodule(obj):
             return lines, 1
         return inspect.getblock(lines[lineno:]), lineno+1
 
     def do_longlist(self, arg):
         """Print lines of code from the current stack frame.
 
         Shows more lines than 'list' does.
         """
         self.lastcmd = 'longlist'
         try:
             lines, lineno = self.getsourcelines(self.curframe)
         except OSError as err:
             self.error(err)
             return
         last = lineno + len(lines)
         self.print_list_lines(self.curframe.f_code.co_filename, lineno, last)
     do_ll = do_longlist
 
     def do_debug(self, arg):
         """debug code
         Enter a recursive debugger that steps through the code
         argument (which is an arbitrary expression or statement to be
         executed in the current environment).
         """
         sys.settrace(None)
         globals = self.curframe.f_globals
         locals = self.curframe_locals
         p = self.__class__(completekey=self.completekey,
                            stdin=self.stdin, stdout=self.stdout)
         p.use_rawinput = self.use_rawinput
         p.prompt = "(%s) " % self.prompt.strip()
         self.message("ENTERING RECURSIVE DEBUGGER")
         sys.call_tracing(p.run, (arg, globals, locals))
         self.message("LEAVING RECURSIVE DEBUGGER")
         sys.settrace(self.trace_dispatch)
         self.lastcmd = p.lastcmd
 
     def do_pdef(self, arg):
         """Print the call signature for any callable object.
 
         The debugger interface to %pdef"""
         namespaces = [('Locals', self.curframe.f_locals),
                       ('Globals', self.curframe.f_globals)]
         self.shell.find_line_magic('pdef')(arg, namespaces=namespaces)
 
     def do_pdoc(self, arg):
         """Print the docstring for an object.
 
         The debugger interface to %pdoc."""
         namespaces = [('Locals', self.curframe.f_locals),
                       ('Globals', self.curframe.f_globals)]
         self.shell.find_line_magic('pdoc')(arg, namespaces=namespaces)
 
     def do_pfile(self, arg):
         """Print (or run through pager) the file where an object is defined.
 
         The debugger interface to %pfile.
         """
         namespaces = [('Locals', self.curframe.f_locals),
                       ('Globals', self.curframe.f_globals)]
         self.shell.find_line_magic('pfile')(arg, namespaces=namespaces)
 
     def do_pinfo(self, arg):
         """Provide detailed information about an object.
 
         The debugger interface to %pinfo, i.e., obj?."""
         namespaces = [('Locals', self.curframe.f_locals),
                       ('Globals', self.curframe.f_globals)]
         self.shell.find_line_magic('pinfo')(arg, namespaces=namespaces)
 
     def do_pinfo2(self, arg):
         """Provide extra detailed information about an object.
 
         The debugger interface to %pinfo2, i.e., obj??."""
         namespaces = [('Locals', self.curframe.f_locals),
                       ('Globals', self.curframe.f_globals)]
         self.shell.find_line_magic('pinfo2')(arg, namespaces=namespaces)
 
     def do_psource(self, arg):
         """Print (or run through pager) the source code for an object."""
         namespaces = [('Locals', self.curframe.f_locals),
                       ('Globals', self.curframe.f_globals)]
         self.shell.find_line_magic('psource')(arg, namespaces=namespaces)
 
     def do_where(self, arg):
         """w(here)
         Print a stack trace, with the most recent frame at the bottom.
         An arrow indicates the "current frame", which determines the
         context of most commands. 'bt' is an alias for this command.
 
         Take a number as argument as an (optional) number of context line to
         print"""
         if arg:
             try:
                 context = int(arg)
             except ValueError as err:
                 self.error(err)
                 return
             self.print_stack_trace(context)
         else:
             self.print_stack_trace()
 
     do_w = do_where
 
     def stop_here(self, frame):
         hidden = False
         if self.skip_hidden:
             hidden = frame.f_locals.get("__tracebackhide__", False)
         if hidden:
             Colors = self.color_scheme_table.active_colors
             ColorsNormal = Colors.Normal
             print(f"{Colors.excName}    [... skipped 1 hidden frame]{ColorsNormal}\n")
 
         return super().stop_here(frame)
 
     def do_up(self, arg):
         """u(p) [count]
         Move the current frame count (default one) levels up in the
         stack trace (to an older frame).
 
         Will skip hidden frames.
         """
         ## modified version of upstream that skips
         # frames with __tracebackide__
         if self.curindex == 0:
             self.error("Oldest frame")
             return
         try:
             count = int(arg or 1)
         except ValueError:
             self.error("Invalid frame count (%s)" % arg)
             return
         skipped = 0
         if count < 0:
             _newframe = 0
         else:
             _newindex = self.curindex
             counter = 0
             hidden_frames = self.hidden_frames(self.stack)
             for i in range(self.curindex - 1, -1, -1):
                 frame = self.stack[i][0]
                 if hidden_frames[i] and self.skip_hidden:
                     skipped += 1
                     continue
                 counter += 1
                 if counter >= count:
                     break
             else:
                 # if no break occured.
-                self.error("all frames above hidden")
+                self.error(
+                    "all frames above hidden, use `skip_hidden False` to get get into those."
+                )
                 return
 
             Colors = self.color_scheme_table.active_colors
             ColorsNormal = Colors.Normal
             _newframe = i
         self._select_frame(_newframe)
         if skipped:
             print(
                 f"{Colors.excName}    [... skipped {skipped} hidden frame(s)]{ColorsNormal}\n"
             )
 
     def do_down(self, arg):
         """d(own) [count]
         Move the current frame count (default one) levels down in the
         stack trace (to a newer frame).
 
         Will skip hidden frames.
         """
         if self.curindex + 1 == len(self.stack):
             self.error("Newest frame")
             return
         try:
             count = int(arg or 1)
         except ValueError:
             self.error("Invalid frame count (%s)" % arg)
             return
         if count < 0:
             _newframe = len(self.stack) - 1
         else:
             _newindex = self.curindex
             counter = 0
             skipped = 0
             hidden_frames = self.hidden_frames(self.stack)
             for i in range(self.curindex + 1, len(self.stack)):
                 frame = self.stack[i][0]
                 if hidden_frames[i] and self.skip_hidden:
                     skipped += 1
                     continue
                 counter += 1
                 if counter >= count:
                     break
             else:
-                self.error("all frames bellow hidden")
+                self.error(
+                    "all frames bellow hidden, use `skip_hidden False` to get get into those."
+                )
                 return
 
             Colors = self.color_scheme_table.active_colors
             ColorsNormal = Colors.Normal
             if skipped:
                 print(
                     f"{Colors.excName}    [... skipped {skipped} hidden frame(s)]{ColorsNormal}\n"
                 )
             _newframe = i
 
         self._select_frame(_newframe)
 
     do_d = do_down
     do_u = do_up
 
 class InterruptiblePdb(Pdb):
     """Version of debugger where KeyboardInterrupt exits the debugger altogether."""
 
     def cmdloop(self):
         """Wrap cmdloop() such that KeyboardInterrupt stops the debugger."""
         try:
             return OldPdb.cmdloop(self)
         except KeyboardInterrupt:
             self.stop_here = lambda frame: False
             self.do_quit("")
             sys.settrace(None)
             self.quitting = False
             raise
 
     def _cmdloop(self):
         while True:
             try:
                 # keyboard interrupts allow for an easy way to cancel
                 # the current command, so allow them during interactive input
                 self.allow_kbdint = True
                 self.cmdloop()
                 self.allow_kbdint = False
                 break
             except KeyboardInterrupt:
                 self.message('--KeyboardInterrupt--')
                 raise
 
 
 def set_trace(frame=None):
     """
     Start debugging from `frame`.
 
     If frame is not specified, debugging starts from caller's frame.
     """
     Pdb().set_trace(frame or sys._getframe().f_back)

IPython/core/ultratb.py

@@ -1,1086 +1,1087 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
 
 import stack_data
 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 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'
 
 # ---------------------------------------------------------------------------
 # 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, 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
 
 
 #---------------------------------------------------------------------------
 # 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):
         # 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
 
         if call_pdb:
             self.pdb = debugger.Pdb()
         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)
 
     def get_parts_of_chained_exception(self, evalue):
         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)
 
         chained_evalue = get_chained_exception(evalue)
 
         if chained_evalue:
             return chained_evalue.__class__, chained_evalue, chained_evalue.__traceback__
 
     def prepare_chained_exception_message(self, cause):
         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):
         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=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=None,
                              context=5, mode=None):
         """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 __init__(self, color_scheme='NoColor', call_pdb=False, ostream=None, parent=None, config=None):
         TBTools.__init__(self, color_scheme=color_scheme, call_pdb=call_pdb,
                          ostream=ostream, parent=parent,config=config)
 
     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, evalue, etb=None, tb_offset=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 : object
             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
         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]
             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 filename, lineno, name, line in extracted_list[:-1]:
             item = '  File %s"%s"%s, line %s%d%s, in %s%s%s\n' % \
                    (Colors.filename, filename, Colors.Normal,
                     Colors.lineno, lineno, Colors.Normal,
                     Colors.name, name, Colors.Normal)
             if line:
                 item += '    %s\n' % line.strip()
             list.append(item)
         # Emphasize the last entry
         filename, lineno, name, line = extracted_list[-1]
         item = '%s  File %s"%s"%s, line %s%d%s, in %s%s%s%s\n' % \
                (Colors.normalEm,
                 Colors.filenameEm, filename, Colors.normalEm,
                 Colors.linenoEm, lineno, Colors.normalEm,
                 Colors.nameEm, name, Colors.normalEm,
                 Colors.Normal)
         if line:
             item += '%s    %s%s\n' % (Colors.line, line.strip(),
                                       Colors.Normal)
         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  File %s"%s"%s, line %s%s%s\n' % \
                             (Colors.normalEm,
                              Colors.filenameEm, py3compat.cast_unicode(value.filename), Colors.normalEm,
                              Colors.linenoEm, 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
         evalue : 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 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)."""
 
     def __init__(self, color_scheme='Linux', call_pdb=False, ostream=None,
                  tb_offset=0, long_header=False, include_vars=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)
         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 is used by the IPython
         # kernel to provide tracebacks for interactive code that is cached,
         # by a compiler instance that flushes the linecache but preserves its
         # own code cache.
         if check_cache is None:
             check_cache = linecache.checkcache
         self.check_cache = check_cache
 
         self.debugger_cls = debugger_cls or debugger.Pdb
         self.skip_hidden = True
 
     def format_record(self, frame_info):
         """Format a single stack frame"""
         Colors = self.Colors  # just a shorthand + quicker name lookup
         ColorsNormal = Colors.Normal  # used a lot
 
 
 
         if isinstance(frame_info, 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_link = '%s%%s%s' % (Colors.filenameEm, ColorsNormal)
         tpl_call = 'in %s%%s%s%%s%s' % (Colors.vName, Colors.valEm,
                                         ColorsNormal)
         tpl_call_fail = 'in %s%%s%s(***failed resolving arguments***)%s' % \
                         (Colors.vName, Colors.valEm, ColorsNormal)
         tpl_local_var = '%s%%s%s' % (Colors.vName, ColorsNormal)
         tpl_name_val = '%%s %s= %%s%s' % (Colors.valEm, ColorsNormal)
 
         file = frame_info.filename
         file = py3compat.cast_unicode(file, util_path.fs_encoding)
         link = tpl_link % util_path.compress_user(file)
         args, varargs, varkw, locals_ = inspect.getargvalues(frame_info.frame)
 
         func = frame_info.executing.code_qualname()
         if func == '<module>':
             call = tpl_call % (func, '')
         else:
             # Decide whether to include variable details or not
             var_repr = eqrepr if self.include_vars else nullrepr
             try:
                 call = tpl_call % (func, inspect.formatargvalues(args,
                                                                  varargs, varkw,
                                                                  locals_, formatvalue=var_repr))
             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:
             for var in frame_info.variables_in_executing_piece:
                 lvals_list.append(tpl_name_val % (var.name, repr(var.value)))
         if lvals_list:
             lvals = '%s%s' % (indent, em_normal.join(lvals_list))
 
         result = '%s %s\n' % (link, call)
 
         result += ''.join(_format_traceback_lines(frame_info.lines, Colors, self.has_colors, lvals))
         return result
 
     def prepare_header(self, etype, long_version=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."
         else:
             # Simplified header
             head = '%s%s' % (exc, 'Traceback (most recent call last)'. \
                              rjust(width - len(str(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, evalue, etb, number_of_lines_of_context, tb_offset):
         """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
         head = self.prepare_header(etype, self.long_header)
         records = self.get_records(etb, number_of_lines_of_context, tb_offset)
 
         frames = []
         skipped = 0
-        for r in records:
+        lastrecord = len(records) - 1
+        for i, r in enumerate(records):
             if not isinstance(r, stack_data.RepeatedFrames) and self.skip_hidden:
-                if r.frame.f_locals.get("__tracebackhide__", 0):
+                if r.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(r))
         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, number_of_lines_of_context, tb_offset):
         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, 'bg:#00005f')
             formatter = Terminal256Formatter(style=style)
         else:
             formatter = None
         options = stack_data.Options(
             before=before,
             after=after,
             pygments_formatter=formatter,
         )
         return list(stack_data.FrameInfo.stack_data(etb, options=options))[tb_offset:]
 
     def structured_traceback(self, etype, evalue, etb, tb_offset=None,
                              number_of_lines_of_context=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:
             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=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:
                     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).  """
 
     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=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:
             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):
         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 ''