New warning: ‘fmt’ may be used uninitialized in this function [-Wmaybe-uninitialized]

[Eclips4]

Bug report

Bug description:

Popped up in https://github.com/python/cpython/pull/116101/files and https://github.com/python/cpython/pull/116096/files

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response

Linked PRs

• gh-116102: Silence a Compiler Warning in _xxinterpqueues #116230

[sobolevn]

Thanks a lot for your helpful reports!

I wanted to post the same :)

[sobolevn]

I think that there are multiple issues here:

» ./python.exe
Python 3.13.0a4+ (heads/main:186fa938766, Feb 29 2024, 13:50:11) [Clang 15.0.0 (clang-1500.0.40.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import _xxinterpqueues
>>> a = _xxinterpqueues.create(2, 0)
>>> _xxinterpqueues.get(a, 'a')
('a', 3)
>>> 
KeyboardInterrupt
>>> ^D
Assertion failed: (queues->count == 0), function _queues_fini, file _xxinterpqueuesmodule.c, line 689.
[1]    57640 abort      ./python.exe

1. Why ('a', 3) is returned? 3 is not the default fmt for this queue
2. Why does it crash? Assertion failed: (queues->count == 0), function _queues_fini, file _xxinterpqueuesmodule.c, line 689.

CC @ericsnowcurrently

[ericsnowcurrently]

1. Why ('a', 3) is returned? 3 is not the default fmt for this queue

It should have raised QueueEmpty. When run your code locally I get QueueEmpty.

2. Why does it crash? Assertion failed: (queues->count == 0), function _queues_fini, file _xxinterpqueuesmodule.c, line 689.

I'm going to look into this.

[ericsnowcurrently]

I've fixed the warning.

As to "Why does it crash?", it's because the low-level module requires you to call _xxinterpqueues.destroy(). Note that I didn't really intend for people to use the low-level module directly. If this is a problem, we can address it separately from this issue.

[sobolevn]

@ericsnowcurrently I will open a new one, because I don't have the same result as you with QueueEmpty :(

[sobolevn]

Done: #116239

[sobolevn]

If this is a problem, we can address it separately from this issue.

Can we call .destroy() on module shut-down? It might fix this problem.
Tell me to open a new issue if you think that this is worth fixing, though :)

[ericsnowcurrently]

Can we call .destroy() on module shut-down? It might fix this problem.

I'm taking care of this in gh-116328.