'Pdb' object has no attribute 'botframe'

[jaraco]

BPO	44461
Nosy	@jaraco, @miss-islington, @iritkatriel
PRs	bpo-44461: Fix bug with pdb's handling of import error due to a packa… #26937 bpo-44461: Check early that a pdb target is valid for execution. #27227 [3.10] bpo-44461: Check early that a pdb target is valid for execution. (GH-27227) #27399 [3.9] bpo-44461: Check early that a pdb target is valid for execution. (GH-27227) #27400

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/jaraco'
closed_at = <Date 2021-07-28.22:50:05.058>
created_at = <Date 2021-06-19.15:55:24.546>
labels = ['library', '3.9', '3.10', '3.11']
title = "'Pdb' object has no attribute 'botframe'"
updated_at = <Date 2021-07-28.22:50:05.057>
user = 'https://github.com/jaraco'

bugs.python.org fields:

activity = <Date 2021-07-28.22:50:05.057>
actor = 'jaraco'
assignee = 'jaraco'
closed = True
closed_date = <Date 2021-07-28.22:50:05.058>
closer = 'jaraco'
components = ['Library (Lib)']
creation = <Date 2021-06-19.15:55:24.546>
creator = 'jaraco'
dependencies = []
files = []
hgrepos = []
issue_num = 44461
keywords = ['patch']
message_count = 13.0
messages = ['396138', '396143', '396144', '396145', '396634', '396635', '396646', '396801', '396914', '398340', '398369', '398437', '398438']
nosy_count = 3.0
nosy_names = ['jaraco', 'miss-islington', 'iritkatriel']
pr_nums = ['26937', '27227', '27399', '27400']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue44461'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']

[jaraco]

While doing some debugging on bpo-44459 using Python 3.10b3, I was using Pdb and after troubleshooting an exception and hitting 'q' to quit, I saw the following:

(Pdb) q
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/pdb.py", line 1709, in main
    pdb._runmodule(mainpyfile)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/pdb.py", line 1541, in _runmodule
    mod_name, mod_spec, code = runpy._get_module_details(module_name)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/runpy.py", line 146, in _get_module_details
    return _get_module_details(pkg_main_name, error)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/runpy.py", line 110, in _get_module_details
    __import__(pkg_name)
  File "/var/folders/c6/v7hnmq453xb6p2dbz1gqc6rr0000gn/T/pip-run-w0xovt3h/rinoh/__init__.py", line 41, in <module>
    from . import resource
  File "/var/folders/c6/v7hnmq453xb6p2dbz1gqc6rr0000gn/T/pip-run-w0xovt3h/rinoh/resource.py", line 205, in <module>
    from .template import DocumentTemplate
  File "/var/folders/c6/v7hnmq453xb6p2dbz1gqc6rr0000gn/T/pip-run-w0xovt3h/rinoh/template.py", line 42, in <module>
    from .stylesheets import sphinx
  File "/var/folders/c6/v7hnmq453xb6p2dbz1gqc6rr0000gn/T/pip-run-w0xovt3h/rinoh/stylesheets/__init__.py", line 42, in <module>
    .format(stylesheet.description, stylesheet))
  File "/var/folders/c6/v7hnmq453xb6p2dbz1gqc6rr0000gn/T/pip-run-w0xovt3h/rinoh/style.py", line 670, in __str__
    for name, entry_point in self.installed_resources:
  File "/var/folders/c6/v7hnmq453xb6p2dbz1gqc6rr0000gn/T/pip-run-w0xovt3h/rinoh/resource.py", line 54, in installed_resources
    for entry_point in ilm.entry_points()[cls.entry_point_group]:
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/importlib/metadata/__init__.py", line 979, in entry_points
    return SelectableGroups.load(eps).select(**params)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/importlib/metadata/__init__.py", line 437, in load
    ordered = sorted(eps, key=by_group)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/importlib/metadata/__init__.py", line -1, in <genexpr>
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/importlib/metadata/_itertools.py", line 16, in unique_everseen
    k = key(element)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/importlib/metadata/__init__.py", line 600, in _normalized_name
    return Prepared.normalize(self.name)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/importlib/metadata/__init__.py", line 841, in normalize
    return re.sub(r"[-_.]+", "-", name).lower().replace('-', '_')
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/re.py", line 187, in sub
    return _compile(pattern, flags).sub(repl, string, count)
TypeError: expected string or bytes-like object

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/pdb.py", line 1738, in <module>
    pdb.main()
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/pdb.py", line 1730, in main
    pdb.interaction(None, t)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/pdb.py", line 357, in interaction
    self._cmdloop()
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/pdb.py", line 322, in _cmdloop
    self.cmdloop()
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/cmd.py", line 138, in cmdloop
    stop = self.onecmd(line)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/pdb.py", line 422, in onecmd
    return cmd.Cmd.onecmd(self, line)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/cmd.py", line 217, in onecmd
    return func(arg)
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/pdb.py", line 1118, in do_quit
    self.set_quit()
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/bdb.py", line 358, in set_quit
    self.stopframe = self.botframe
AttributeError: 'Pdb' object has no attribute 'botframe'. Did you mean: 'curframe'?

I'd not seen this error before, so I suspect there may be a regression in 3.10. I haven't investigated further, but I wanted to register this possible issue.

[jaraco]

I encountered the same error on Python 3.9.

[jaraco]

I can replicate the issue with this command: python -m pdb -m importlib (since importlib isn't executable, it triggers an error in runpy).

[jaraco]

I was unable to replicate the issue with a foo.py containing only raise ValueError, even with python -m pdb -m foo.

[iritkatriel]

The difference between Jason's two test cases is which stage of Pdb._runmodule() fails.

In the case of python -m pdb -m importlib runpy._get_module_details(module_name) raises an exception because importlib is a package and it looks for its main, so self.run(code) is never called.

In the case of python -m pdb -m foo with foo that raises an exception, foo is not a package so the main check doesn't happen. The exception comes from within the self.run(code) call (when the module is executed). self.run() calls self.reset() before executing the code, and reset() calls Bdb.reset() which initializes self.botframe (to None).

[iritkatriel]

However, if we just try to initialize self.botframe to None in __init__, then 'quit' doesn't work anymore, so something else needs to be done about cleanup when import fails at that stage.

[iritkatriel]

The cleanup issue was in the except: clause of the main loop: if the user does quit() during the pdb.interaction() call upon an unhandled exception ("the post mortem debugger"), then this quit request is ignored and the program just restarts.

The attached patch fixes this by checking for quit requests after the port-mortem debugger returns.