path: root/contrib/python/ipython/py3/IPython/core/debugger.py

"""
Pdb debugger class.


This is an extension to PDB which adds a number of new features.
Note that there is also the `IPython.terminal.debugger` class which provides UI
improvements.

We also strongly recommend to use this via the `ipdb` package, which provides
extra configuration options.

Among other things, this subclass of PDB:
 - supports many IPython magics like pdef/psource
 - hide frames in tracebacks based on `__tracebackhide__`
 - allows to skip frames based on `__debuggerskip__`


Global Configuration
--------------------

The IPython debugger will by read the global ``~/.pdbrc`` file.
That is to say you can list all commands supported by ipdb in your `~/.pdbrc`
configuration file, to globally configure pdb.

Example::

   # ~/.pdbrc
   skip_predicates debuggerskip false
   skip_hidden false
   context 25

Features
--------

The IPython debugger can hide and skip frames when printing or moving through
the stack. This can have a performance impact, so can be configures.

The skipping and hiding frames are configurable via the `skip_predicates`
command.

By default, frames from readonly files will be hidden, frames containing
``__tracebackhide__ = True`` will be hidden.

Frames containing ``__debuggerskip__`` will be stepped over, frames whose parent
frames value of ``__debuggerskip__`` is ``True`` will also be skipped.

    >>> def helpers_helper():
    ...     pass
    ...
    ... def helper_1():
    ...     print("don't step in me")
    ...     helpers_helpers() # will be stepped over unless breakpoint set.
    ...
    ...
    ... def helper_2():
    ...     print("in me neither")
    ...

One can define a decorator that wraps a function between the two helpers:

    >>> def pdb_skipped_decorator(function):
    ...
    ...
    ...     def wrapped_fn(*args, **kwargs):
    ...         __debuggerskip__ = True
    ...         helper_1()
    ...         __debuggerskip__ = False
    ...         result = function(*args, **kwargs)
    ...         __debuggerskip__ = True
    ...         helper_2()
    ...         # setting __debuggerskip__ to False again is not necessary
    ...         return result
    ...
    ...     return wrapped_fn

When decorating a function, ipdb will directly step into ``bar()`` by
default:

    >>> @foo_decorator
    ... def bar(x, y):
    ...     return x * y


You can toggle the behavior with

    ipdb> skip_predicates debuggerskip false

or configure it in your ``.pdbrc``



License
-------

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 original 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


All the changes since then are under the same license as IPython.

"""

#*****************************************************************************
#
#       This file is licensed under the PSF license.
#
#       Copyright (C) 2001 Python Software Foundation, www.python.org
#       Copyright (C) 2005-2006 Fernando Perez. <fperez@colorado.edu>
#
#
#*****************************************************************************

from __future__ import annotations

import inspect
import linecache
import os
import re
import sys
from contextlib import contextmanager
from functools import lru_cache

from IPython import get_ipython
from IPython.core.excolors import exception_colors
from IPython.utils import PyColorize, coloransi, py3compat

from typing import TYPE_CHECKING

if TYPE_CHECKING:
    # otherwise circular import
    from IPython.core.interactiveshell import InteractiveShell

# skip module docstests
__skip_doctest__ = True

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.

DEBUGGERSKIP = "__debuggerskip__"


# this has been implemented in Pdb in Python 3.13 (https://github.com/python/cpython/pull/106676
# on lower python versions, we backported the feature.
CHAIN_EXCEPTIONS = sys.version_info < (3, 13)


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.
    """
    raise ValueError(
        "`BdbQuit_excepthook` is deprecated since version 5.1. It is still around only because it is still imported by ipdb.",
    )


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()`


    This debugger can hide and skip frames that are tagged according to some predicates.
    See the `skip_predicates` commands.

    """

    shell: InteractiveShell

    if CHAIN_EXCEPTIONS:
        MAX_CHAINED_EXCEPTION_DEPTH = 999

    default_predicates = {
        "tbhide": True,
        "readonly": False,
        "ipython_internal": True,
        "debuggerskip": True,
    }

    def __init__(self, completekey=None, stdin=None, stdout=None, context=5, **kwargs):
        """Create a new IPython debugger.

        Parameters
        ----------
        completekey : default None
            Passed to pdb.Pdb.
        stdin : default None
            Passed to pdb.Pdb.
        stdout : default None
            Passed to pdb.Pdb.
        context : int
            Number of lines of source code context to show when
            displaying stacktrace information.
        **kwargs
            Passed to pdb.Pdb.

        Notes
        -----
        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


        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


        # 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
        self.report_skipped = True

        # list of predicates we use to skip frames
        self._predicates = self.default_predicates

        if CHAIN_EXCEPTIONS:
            self._chained_exceptions = tuple()
            self._chained_exception_index = 0

    #
    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 set_trace(self, frame=None):
        if frame is None:
            frame = sys._getframe().f_back
        self.initial_frame = frame
        return super().set_trace(frame)

    def _hidden_predicate(self, frame):
        """
        Given a frame return whether it it should be hidden or not by IPython.
        """

        if self._predicates["readonly"]:
            fname = frame.f_code.co_filename
            # we need to check for file existence and interactively define
            # function would otherwise appear as RO.
            if os.path.isfile(fname) and not os.access(fname, os.W_OK):
                return True

        if self._predicates["tbhide"]:
            if frame in (self.curframe, getattr(self, "initial_frame", None)):
                return False
            frame_locals = self._get_frame_locals(frame)
            if "__tracebackhide__" not in frame_locals:
                return False
            return frame_locals["__tracebackhide__"]
        return False

    def hidden_frames(self, stack):
        """
        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.
        # Furthermore, there is no good reason to hide the current frame.
        ip_hide = [self._hidden_predicate(s[0]) for s in stack]
        ip_start = [i for i, s in enumerate(ip_hide) if s == "__ipython_bottom__"]
        if ip_start and self._predicates["ipython_internal"]:
            ip_hide = [h if i > ip_start[0] else True for (i, h) in enumerate(ip_hide)]
        return ip_hide

    if CHAIN_EXCEPTIONS:

        def _get_tb_and_exceptions(self, tb_or_exc):
            """
            Given a tracecack or an exception, return a tuple of chained exceptions
            and current traceback to inspect.
            This will deal with selecting the right ``__cause__`` or ``__context__``
            as well as handling cycles, and return a flattened list of exceptions we
            can jump to with do_exceptions.
            """
            _exceptions = []
            if isinstance(tb_or_exc, BaseException):
                traceback, current = tb_or_exc.__traceback__, tb_or_exc

                while current is not None:
                    if current in _exceptions:
                        break
                    _exceptions.append(current)
                    if current.__cause__ is not None:
                        current = current.__cause__
                    elif (
                        current.__context__ is not None
                        and not current.__suppress_context__
                    ):
                        current = current.__context__

                    if len(_exceptions) >= self.MAX_CHAINED_EXCEPTION_DEPTH:
                        self.message(
                            f"More than {self.MAX_CHAINED_EXCEPTION_DEPTH}"
                            " chained exceptions found, not all exceptions"
                            "will be browsable with `exceptions`."
                        )
                        break
            else:
                traceback = tb_or_exc
            return tuple(reversed(_exceptions)), traceback

        @contextmanager
        def _hold_exceptions(self, exceptions):
            """
            Context manager to ensure proper cleaning of exceptions references
            When given a chained exception instead of a traceback,
            pdb may hold references to many objects which may leak memory.
            We use this context manager to make sure everything is properly cleaned
            """
            try:
                self._chained_exceptions = exceptions
                self._chained_exception_index = len(exceptions) - 1
                yield
            finally:
                # we can't put those in forget as otherwise they would
                # be cleared on exception change
                self._chained_exceptions = tuple()
                self._chained_exception_index = 0

        def do_exceptions(self, arg):
            """exceptions [number]
            List or change current exception in an exception chain.
            Without arguments, list all the current exception in the exception
            chain. Exceptions will be numbered, with the current exception indicated
            with an arrow.
            If given an integer as argument, switch to the exception at that index.
            """
            if not self._chained_exceptions:
                self.message(
                    "Did not find chained exceptions. To move between"
                    " exceptions, pdb/post_mortem must be given an exception"
                    " object rather than a traceback."
                )
                return
            if not arg:
                for ix, exc in enumerate(self._chained_exceptions):
                    prompt = ">" if ix == self._chained_exception_index else " "
                    rep = repr(exc)
                    if len(rep) > 80:
                        rep = rep[:77] + "..."
                    indicator = (
                        "  -"
                        if self._chained_exceptions[ix].__traceback__ is None
                        else f"{ix:>3}"
                    )
                    self.message(f"{prompt} {indicator} {rep}")
            else:
                try:
                    number = int(arg)
                except ValueError:
                    self.error("Argument must be an integer")
                    return
                if 0 <= number < len(self._chained_exceptions):
                    if self._chained_exceptions[number].__traceback__ is None:
                        self.error(
                            "This exception does not have a traceback, cannot jump to it"
                        )
                        return

                    self._chained_exception_index = number
                    self.setup(None, self._chained_exceptions[number].__traceback__)
                    self.print_stack_entry(self.stack[self.curindex])
                else:
                    self.error("No exception with that number")

    def interaction(self, frame, tb_or_exc):
        try:
            if CHAIN_EXCEPTIONS:
                # this context manager is part of interaction in 3.13
                _chained_exceptions, tb = self._get_tb_and_exceptions(tb_or_exc)
                if isinstance(tb_or_exc, BaseException):
                    assert tb is not None, "main exception must have a traceback"
                with self._hold_exceptions(_chained_exceptions):
                    OldPdb.interaction(self, frame, tb)
            else:
                OldPdb.interaction(self, frame, tb_or_exc)

        except KeyboardInterrupt:
            self.stdout.write("\n" + self.shell.get_exception_only())

    def precmd(self, line):
        """Perform useful escapes on the command before it is executed."""

        if line.endswith("??"):
            line = "pinfo2 " + line[:-2]
        elif line.endswith("?"):
            line = "pinfo " + line[:-1]

        line = super().precmd(line)

        return line

    def new_do_quit(self, arg):
        return OldPdb.do_quit(self, arg)

    do_q = do_quit = decorate_fn_with_doc(new_do_quit, OldPdb.do_quit)

    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 _get_frame_locals(self, frame):
        """ "
        Accessing f_local of current frame reset the namespace, so we want to avoid
        that or the following can happen

        ipdb> foo
        "old"
        ipdb> foo = "new"
        ipdb> foo
        "new"
        ipdb> where
        ipdb> foo
        "old"

        So if frame is self.current_frame we instead return self.curframe_locals

        """
        if frame is self.curframe:
            return self.curframe_locals
        else:
            return frame.f_locals

    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 = "%s%%s%s" % (Colors.filenameEm, ColorsNormal)
        tpl_call = "%s%%s%s%%s%s" % (Colors.vName, Colors.valEm, ColorsNormal)
        tpl_line = "%%s%s%%s %s%%s" % (Colors.lineno, ColorsNormal)
        tpl_line_em = "%%s%s%%s %s%%s%s" % (Colors.linenoEm, Colors.line, ColorsNormal)

        frame, lineno = frame_lineno

        return_value = ''
        loc_frame = self._get_frame_locals(frame)
        if "__return__" in loc_frame:
            rv = loc_frame["__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 loc_frame:
                args = reprlib.repr(loc_frame["__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("%s(%s)%s\n" % (link, lineno, call))

        start = lineno - 1 - context//2
        lines = linecache.getlines(filename, frame.f_globals)
        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, self.curframe.f_globals)
                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_predicates(self, args):
        """
        Turn on/off individual predicates as to whether a frame should be hidden/skip.

        The global option to skip (or not) hidden frames is set with skip_hidden

        To change the value of a predicate

            skip_predicates key [true|false]

        Call without arguments to see the current values.

        To permanently change the value of an option add the corresponding
        command to your ``~/.pdbrc`` file. If you are programmatically using the
        Pdb instance you can also change the ``default_predicates`` class
        attribute.
        """
        if not args.strip():
            print("current predicates:")
            for p, v in self._predicates.items():
                print("   ", p, ":", v)
            return
        type_value = args.strip().split(" ")
        if len(type_value) != 2:
            print(
                f"Usage: skip_predicates <type> <value>, with <type> one of {set(self._predicates.keys())}"
            )
            return

        type_, value = type_value
        if type_ not in self._predicates:
            print(f"{type_!r} not in {set(self._predicates.keys())}")
            return
        if value.lower() not in ("true", "yes", "1", "no", "false", "0"):
            print(
                f"{value!r} is invalid - use one of ('true', 'yes', '1', 'no', 'false', '0')"
            )
            return

        self._predicates[type_] = value.lower() in ("true", "yes", "1")
        if not any(self._predicates.values()):
            print(
                "Warning, all predicates set to False, skip_hidden may not have any effects."
            )

    def do_skip_hidden(self, arg):
        """
        Change whether or not we should skip frames with the
        __tracebackhide__ attribute.
        """
        if not arg.strip():
            print(
                f"skip_hidden = {self.skip_hidden}, use 'yes','no', 'true', or 'false' to change."
            )
        elif arg.strip().lower() in ("true", "yes"):
            self.skip_hidden = True
        elif arg.strip().lower() in ("false", "no"):
            self.skip_hidden = False
        if not any(self._predicates.values()):
            print(
                "Warning, all predicates set to False, skip_hidden may not have any effects."
            )

    def do_list(self, arg):
        """Print lines of code from the current stack frame
        """
        self.lastcmd = 'list'
        last = None
        if arg and 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 or arg == ".":
            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 self._get_frame_locals(obj):
            # 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).
        """
        trace_function = sys.gettrace()
        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(trace_function)
        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_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_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_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_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_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_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 break_anywhere(self, frame):
        """
        _stop_in_decorator_internals is overly restrictive, as we may still want
        to trace function calls, so we need to also update break_anywhere so
        that is we don't `stop_here`, because of debugger skip, we may still
        stop at any point inside the function

        """

        sup = super().break_anywhere(frame)
        if sup:
            return sup
        if self._predicates["debuggerskip"]:
            if DEBUGGERSKIP in frame.f_code.co_varnames:
                return True
            if frame.f_back and self._get_frame_locals(frame.f_back).get(DEBUGGERSKIP):
                return True
        return False

    def _is_in_decorator_internal_and_should_skip(self, frame):
        """
        Utility to tell us whether we are in a decorator internal and should stop.

        """
        # if we are disabled don't skip
        if not self._predicates["debuggerskip"]:
            return False

        return self._cachable_skip(frame)

    @lru_cache(1024)
    def _cached_one_parent_frame_debuggerskip(self, frame):
        """
        Cache looking up for DEBUGGERSKIP on parent frame.

        This should speedup walking through deep frame when one of the highest
        one does have a debugger skip.

        This is likely to introduce fake positive though.
        """
        while getattr(frame, "f_back", None):
            frame = frame.f_back
            if self._get_frame_locals(frame).get(DEBUGGERSKIP):
                return True
        return None

    @lru_cache(1024)
    def _cachable_skip(self, frame):
        # if frame is tagged, skip by default.
        if DEBUGGERSKIP in frame.f_code.co_varnames:
            return True

        # if one of the parent frame value set to True skip as well.
        if self._cached_one_parent_frame_debuggerskip(frame):
            return True

        return False

    def stop_here(self, frame):
        if self._is_in_decorator_internal_and_should_skip(frame) is True:
            return False

        hidden = False
        if self.skip_hidden:
            hidden = self._hidden_predicate(frame)
        if hidden:
            if self.report_skipped:
                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 __tracebackhide__
        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:
            counter = 0
            hidden_frames = self.hidden_frames(self.stack)
            for i in range(self.curindex - 1, -1, -1):
                if hidden_frames[i] and self.skip_hidden:
                    skipped += 1
                    continue
                counter += 1
                if counter >= count:
                    break
            else:
                # if no break occurred.
                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:
            counter = 0
            skipped = 0
            hidden_frames = self.hidden_frames(self.stack)
            for i in range(self.curindex + 1, len(self.stack)):
                if hidden_frames[i] and self.skip_hidden:
                    skipped += 1
                    continue
                counter += 1
                if counter >= count:
                    break
            else:
                self.error(
                    "all frames below 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

    def do_context(self, context):
        """context number_of_lines
        Set the number of lines of source code to show when displaying
        stacktrace information.
        """
        try:
            new_context = int(context)
            if new_context <= 0:
                raise ValueError()
            self.context = new_context
        except ValueError:
            self.error(
                f"The 'context' command requires a positive integer argument (current value {self.context})."
            )


class InterruptiblePdb(Pdb):
    """Version of debugger where KeyboardInterrupt exits the debugger altogether."""

    def cmdloop(self, intro=None):
        """Wrap cmdloop() such that KeyboardInterrupt stops the debugger."""
        try:
            return OldPdb.cmdloop(self, intro=intro)
        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, header=None):
    """
    Start debugging from `frame`.

    If frame is not specified, debugging starts from caller's frame.
    """
    pdb = Pdb()
    if header is not None:
        pdb.message(header)
    pdb.set_trace(frame or sys._getframe().f_back)