Description

jonathanslenders

opened on Feb 2, 2023

Issue body actions

Bug report

Consider this code:

from asyncio import run, TaskGroup

async def bad_function():
    raise ZeroDivisionError
async def bad_function2():
    raise KeyError

async def main():
    try:
        async with TaskGroup() as tg:
            tg.create_task(bad_function())
            tg.create_task(bad_function2())

    except* ZeroDivisionError as e:
        breakpoint()


run(main())

Run it on Python 3.11 or 3.12:

--Return--
Traceback (most recent call last):
  File "....py", line 18, in <module>
    run(main())
  File "/home/jonathan/.pyenv/versions/3.11.0/lib/python3.11/asyncio/runners.py", line 190, in run
    return runner.run(main)
           ^^^^^^^^^^^^^^^^
  File "/home/jonathan/.pyenv/versions/3.11.0/lib/python3.11/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jonathan/.pyenv/versions/3.11.0/lib/python3.11/asyncio/base_events.py", line 650, in run_until_complete
    return future.result()
           ^^^^^^^^^^^^^^^
  File ".....py", line -1, in main
  File "/home/jonathan/.pyenv/versions/3.11.0/lib/python3.11/bdb.py", line 94, in trace_dispatch
    return self.dispatch_return(frame, arg)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jonathan/.pyenv/versions/3.11.0/lib/python3.11/bdb.py", line 153, in dispatch_return
    self.user_return(frame, arg)
  File "/home/jonathan/.pyenv/versions/3.11.0/lib/python3.11/pdb.py", line 372, in user_return
    self.interaction(frame, None)
  File "/home/jonathan/.pyenv/versions/3.11.0/lib/python3.11/pdb.py", line 434, in interaction
    self.print_stack_entry(self.stack[self.curindex])
  File "/home/jonathan/.pyenv/versions/3.11.0/lib/python3.11/pdb.py", line 1554, in print_stack_entry
    self.format_stack_entry(frame_lineno, prompt_prefix))
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jonathan/.pyenv/versions/3.11.0/lib/python3.11/bdb.py", line 573, in format_stack_entry
    line = linecache.getline(filename, lineno, frame.f_globals)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/jonathan/.pyenv/versions/3.11.0/lib/python3.11/linecache.py", line 31, in getline
    if 1 <= lineno <= len(lines):
TypeError: '<=' not supported between instances of 'int' and 'NoneType'

One of the exceptions has to be a ZeroDivisionError for it to happen as far as I can see.

Your environment

• CPython versions tested on: 3.11, 3.12
• Operating system and architecture: Linux, M1, arm64

Linked PRs

• gh-101517: Fix missing linenumber for re-raise in except* #101663
• gh-101517: Attach line number to the RERAISE at the end of a try-except* #101768
• gh-101517: bdb should not lookup linecache with lineno=None #101787
• [3.11] gh-101517: make bdb avoid looking up in linecache with lineno=None (GH-101787) #101793
• [3.10] gh-101517: make bdb avoid looking up in linecache with lineno=None (GH-101787) #101794
• gh-101517: propagate lasti with RERAISE 1 in except* handling to get currect line numbers #103529
• gh-101517: Add regression test for entering pdb in try/except* block #103547
• gh-101517: fix line number propagation in code generated for except* #103550
• [3.11] gh-101517: fix line number propagation in code generated for except* (#103550) #103816

Activity

1. jonathanslenders

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Feb 2, 2023
2. arhadthedev

   added

   topic-asyncio

   on Feb 2, 2023
3. ezio-melotti

   added this to asyncioon Feb 2, 2023
4. github-project-automation

   moved this to Todo in asyncioon Feb 2, 2023
5. gvanrossum commented on Feb 2, 2023

   

   gvanrossum

   on Feb 2, 2023

   Member

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   Can you produce a repro without asyncio? I suspect you can get this by just raising and catching two errors and then raise an ExceptionGroup. @iritkatriel
6. iritkatriel commented on Feb 2, 2023

   

   iritkatriel

   on Feb 2, 2023

   Member

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   It's something to do with a breakpoint as the last thing in an except block.

   Without asyncio:

   excs = []
   try:
       raise ZeroDivisionError
   except Exception as e:
       excs.append(e)
   
   try:
       raise KeyError
   except Exception as e:
       excs.append(e)
   
   
   def main():
       try:
           raise ExceptionGroup("eg", excs)
       except* ZeroDivisionError as e:
           breakpoint()
           # pass    # <-- uncomment this and the problem goes away
   
   main()
   
   
7. iritkatriel

   added

   3.11only security fixesonly security fixes

   3.12only security fixesonly security fixes

   and removed

   topic-asyncio

   on Feb 2, 2023
8. AlexWaygood

   removed this from asyncioon Feb 2, 2023
9. iritkatriel commented on Feb 2, 2023

   

   iritkatriel

   on Feb 2, 2023

   Member

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   Something to do with frame initialisation? @markshannon @brandtbucher

   excs = []
   try:
       raise ZeroDivisionError
   except Exception as e:
       excs.append(e)
   
   try:
       raise KeyError
   except Exception as e:
       excs.append(e)
   
   def main():
       try:
           raise ExceptionGroup("eg", excs)
       except* ZeroDivisionError as e:
           #sys._getframe()     # <-- uncomment this and the problem goes away
           breakpoint()
   
   
   main()
   
   
10. brandtbucher commented on Feb 2, 2023

    

    brandtbucher

    on Feb 2, 2023

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    I don't see the problem going away when I add the sys._getframe() call...
11. brandtbucher commented on Feb 2, 2023

    

    brandtbucher

    on Feb 2, 2023

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    This does reproduce the issue for me, though:

    try:
        raise ExceptionGroup("eg", [KeyError(), ValueError()])
    except* KeyError:
        breakpoint()
        # pass    # <-- uncomment this and the problem goes away
12. brandtbucher commented on Feb 2, 2023

    

    brandtbucher

    on Feb 2, 2023

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    Note that this only reproduces if some exceptions are uncaught (the ValueError, in my above example... turning it into a KeyError makes the issue go away).
13. iritkatriel commented on Feb 2, 2023

    

    iritkatriel

    on Feb 2, 2023

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    I think it's some kind of heisenbug. I worked around the lineno being None in linecache.py:31, then it failed on None in another place later on, so I added a "print the frame" just before that line, and the problem went away.
14. 32 remaining items

15. gaogaotiantian commented on Apr 14, 2023

    

    gaogaotiantian

    on Apr 14, 2023

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    How could pdb know it is "wrong"? It can be a real bummer when the debugger itself crashes, so I just want it to keep working as well as it can. Sometimes the debugger is being used to track down bugs in the compiler.

    Sure we can try to make the debugger work even if python is not working properly. I guess we can generate a warning for f_lineno is None but not crash - so the user know something is wrong, but it'll still work on some commands.

    Reacted by Irit Katriel, Guido van Rossum and Alex Waygood
16. iritkatriel

    added 4 commits that reference this issue on Apr 14, 2023

    gh-101517: Add regression test for a lineno bug in try/except* impact…

    7c1b0a4

    pythongh-101517: propagate lasti with RERAISE 1 in except* handling t…

    5b54131

    pythongh-101517: fix line number propagation in code generated for ex…

    674f558

    pythongh-101517: fix line number propagation in code generated for ex…

    eb2b5a5
17. iritkatriel commented on Apr 14, 2023

    

    iritkatriel

    on Apr 14, 2023

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    PR is here: #103550

    I didn't use the warnings module, just print like in a few other places in this module (I'm assuming there's a good reason for that).
18. carljm

    added 2 commits that reference this issue on Apr 17, 2023

    Merge branch 'main' into superopt

    5136459

    Merge branch 'superopt' into superopt_spec

    079c65a
19. iritkatriel

    added a commit that references this issue on Apr 24, 2023

    gh-101517: fix line number propagation in code generated for except* (#…

    1c01f8d
20. carljm

    added 2 commits that reference this issue on Apr 24, 2023

    Merge branch 'main' into superopt

    0de5bc6

    Merge branch 'superopt' into superopt_spec

    1972ca4
21. iritkatriel

    added 2 commits that reference this issue on Apr 25, 2023

    pythongh-101517: fix line number propagation in code generated for ex…

    e62d5d9

    [3.11] gh-101517: fix line number propagation in code generated for e…

    93a9535
22. iritkatriel commented on Apr 25, 2023

    

    iritkatriel

    on Apr 25, 2023

    Member

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    This was fixed (in 3.11 as well). We will follow up on the more general problem in #103795.
23. iritkatriel

    closed this as completedon Apr 25, 2023

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