mypyc 1.16 regression: x86_64-cpython-3{9,10,11,12,13} error: ‘FOO_finalize’ undeclared here (not in a function); did you mean ‘FOO_init’?

[mr-c]

Crash Report
compiling Python modules using mypyc failed with a gcc error, where it did not using mypy 1.15

Python 3.9: https://github.com/common-workflow-language/schema_salad/actions/runs/15347015751/job/43185437280?pr=927#step:6:450

Python 3.10: https://github.com/common-workflow-language/schema_salad/actions/runs/15347015751/job/43185437282?pr=927#step:6:439

Python 3.11: https://github.com/common-workflow-language/schema_salad/actions/runs/15347015751/job/43185437303?pr=927#step:6:433

Python 3.12: https://github.com/common-workflow-language/schema_salad/actions/runs/15347015751/job/43185437295?pr=927#step:6:425

Python 3.13: https://github.com/common-workflow-language/schema_salad/actions/runs/15347015751/job/43185437315?pr=927#step:6:425

Traceback

    building '5df31530eea7292b5dae__mypyc' extension
    creating build/temp.linux-x86_64-cpython-39/build
    gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -fPIC -I/tmp/pip-build-env-qntpj1xx/overlay/lib/python3.9/site-packages/mypyc/lib-rt -Ibuild -I/opt/_internal/cpython-3.9.22/include/python3.9 -c build/__native_5df31530eea7292b5dae.c -o build/temp.linux-x86_64-cpython-39/build/__native_5df31530eea7292b5dae.o -O3 -g0 -Werror -Wno-unused-function -Wno-unused-label -Wno-unreachable-code -Wno-unused-variable -Wno-unused-command-line-argument -Wno-unknown-warning-option -Wno-unused-but-set-variable -Wno-ignored-optimization-argument -Wno-cpp
    build/__native_5df31530eea7292b5dae.c:110530:32: error: ‘ref_resolver___NormDict_finalize’ undeclared here (not in a function); did you mean ‘ref_resolver___NormDict_init’?
    110530 |     .tp_finalize = (destructor)ref_resolver___NormDict_finalize,
           |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           |                                ref_resolver___NormDict_init
    cc1: note: unrecognized command-line option ‘-Wno-ignored-optimization-argument’ may have been intended to silence earlier diagnostics
    cc1: note: unrecognized command-line option ‘-Wno-unknown-warning-option’ may have been intended to silence earlier diagnostics
    cc1: note: unrecognized command-line option ‘-Wno-unused-command-line-argument’ may have been intended to silence earlier diagnostics
    error: command '/opt/rh/gcc-toolset-14/root/usr/bin/gcc' failed with exit code 1
    error: subprocess-exited-with-error
    
    × Building wheel for schema-salad (pyproject.toml) did not run successfully.
    │ exit code: 1
    ╰─> See above for output.

To Reproduce

1. Checkout https://github.com/common-workflow-language/schema_salad/tree/dependabot/pip/mypy-mypyc--1.16.0
2. tox -e py39-mypy (or py310-mypy, up to py313-mypy); or make a virtualenv and activate it, and make dev mypyc

Your Environment

• Mypy version used: 1.16
• Mypy command-line flags: MYPYPATH=mypy-stubs SCHEMA_SALAD_USE_MYPYC=1 pip install --verbose -e .
• Mypy configuration options from mypy.ini (and other config files): https://github.com/common-workflow-language/schema_salad/blob/dependabot/pip/mypy-mypyc--1.16.0/mypy.ini
• Python version used: 3.9 - 3.13
• Operating system and version: Ubuntu Linux 24.04.2

[JukkaL]

Thanks for reporting the issue! The next step would be to find the root cause by bisecting mypy and mypyc commits.

[JukkaL]

This PR looks related:

• [mypyc] Calling tp_finalize from tp_dealloc. #18519

Now we need a self-contained reproducer, which we can use to check if the above PR is the root cause, or to bisect across all commits otherwise.

[mr-c]

Thank you @JukkaL ; I have to finish other work right now, so I can't dig in further today. Here's the is Python source code for the class related to the error: https://github.com/common-workflow-language/schema_salad/blob/0f8e2e888b38bff4e07a91807da430ca2a635376/schema_salad/ref_resolver.py#L96-L119

[mr-c]

I nerdsniped myself, here is a minimal reproducer

ref_resolver.py

from typing import Any, Callable, Union

from ruamel.yaml.comments import CommentedMap, CommentedSeq

class NormDict(dict[str, Union[CommentedMap, CommentedSeq, str, None]]):
    """A Dict where all keys are normalized using the provided function."""

    def __init__(self, normalize: Callable[[str], str] = str) -> None:
        super().__init__()
        self.normalize = normalize

    def __eq__(self, other: Any) -> bool:
        return super().__eq__(other)

    def __getitem__(self, key: Any) -> Any:
        return super().__getitem__(self.normalize(key))

    def __setitem__(self, key: Any, value: Any) -> Any:
        return super().__setitem__(self.normalize(key), value)

    def __delitem__(self, key: Any) -> Any:
        return super().__delitem__(self.normalize(key))

    def __contains__(self, key: Any) -> bool:
        return super().__contains__(self.normalize(key))

    def __del__(self) -> None:
        del self.normalize

$ pip install mypy==1.15.0
[…]
$ mypyc ref_resolver.py 
running build_ext
building 'ref_resolver' extension
creating build/temp.linux-x86_64-cpython-311
creating build/temp.linux-x86_64-cpython-311/build
x86_64-linux-gnu-gcc -Wsign-compare -DNDEBUG -g -fwrapv -O2 -Wall -g -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -g -fwrapv -O2 -fPIC -I/home/michael/ss2/env3.11/lib/python3.11/site-packages/mypyc/lib-rt -I/home/michael/ss2/env3.11/include -I/usr/include/python3.11 -c build/__native.c -o build/temp.linux-x86_64-cpython-311/build/__native.o -O3 -g1 -Werror -Wno-unused-function -Wno-unused-label -Wno-unreachable-code -Wno-unused-variable -Wno-unused-command-line-argument -Wno-unknown-warning-option -Wno-unused-but-set-variable -Wno-ignored-optimization-argument -Wno-cpp
creating build/lib.linux-x86_64-cpython-311
x86_64-linux-gnu-gcc -shared -Wl,-O1 -Wl,-Bsymbolic-functions -g -fwrapv -O2 build/temp.linux-x86_64-cpython-311/build/__native.o -L/usr/lib/x86_64-linux-gnu -o build/lib.linux-x86_64-cpython-311/ref_resolver.cpython-311-x86_64-linux-gnu.so
copying build/lib.linux-x86_64-cpython-311/ref_resolver.cpython-311-x86_64-linux-gnu.so ->

$ rm -Rf ref_resolver.*.so .mypy_cache/ build/
$ pip install mypy==1.16.0
[…]
$ mypyc ref_resolver.py 
running build_ext
building 'ref_resolver' extension
creating build/temp.linux-x86_64-cpython-311
creating build/temp.linux-x86_64-cpython-311/build
x86_64-linux-gnu-gcc -Wsign-compare -DNDEBUG -g -fwrapv -O2 -Wall -g -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection -g -fwrapv -O2 -fPIC -I/home/michael/ss2/env3.11/lib/python3.11/site-packages/mypyc/lib-rt -I/home/michael/ss2/env3.11/include -I/usr/include/python3.11 -c build/__native.c -o build/temp.linux-x86_64-cpython-311/build/__native.o -O3 -g1 -Werror -Wno-unused-function -Wno-unused-label -Wno-unreachable-code -Wno-unused-variable -Wno-unused-command-line-argument -Wno-unknown-warning-option -Wno-unused-but-set-variable -Wno-ignored-optimization-argument -Wno-cpp
build/__native.c:162:32: error: ‘NormDict_finalize’ undeclared here (not in a function); did you mean ‘NormDict_init’?
  162 |     .tp_finalize = (destructor)NormDict_finalize,
      |                                ^~~~~~~~~~~~~~~~~
      |                                NormDict_init
cc1: note: unrecognized command-line option ‘-Wno-ignored-optimization-argument’ may have been intended to silence earlier diagnostics
cc1: note: unrecognized command-line option ‘-Wno-unknown-warning-option’ may have been intended to silence earlier diagnostics
cc1: note: unrecognized command-line option ‘-Wno-unused-command-line-argument’ may have been intended to silence earlier diagnostics
error: command '/usr/lib/ccache/x86_64-linux-gnu-gcc' failed with exit code 1
$ x86_64-linux-gnu-gcc --version
x86_64-linux-gnu-gcc (Debian 12.2.0-14+deb12u1) 12.2.0

[JelleZijlstra]

You nerd-sniped me further because surely that's too complex for a minimal reproducer. This still reproduces it:

class NormDict(dict):
    def __del__(self) -> None:
        pass

$ mypyc mypyc_crash.py 
running build_ext
building 'mypyc_crash' extension
clang -fno-strict-overflow -Wsign-compare -Wunreachable-code -DNDEBUG -g -O3 -Wall -I/Users/jelle/py/venvs/taxonomy312/lib/python3.12/site-packages/mypyc/lib-rt -I/Users/jelle/py/venvs/taxonomy312/include -I/Users/jelle/.pyenv/versions/3.12.2/include/python3.12 -c build/__native.c -o build/temp.macosx-14.4-arm64-cpython-312/build/__native.o -O3 -g1 -Werror -Wno-unused-function -Wno-unused-label -Wno-unreachable-code -Wno-unused-variable -Wno-unused-command-line-argument -Wno-unknown-warning-option -Wno-unused-but-set-variable -Wno-ignored-optimization-argument -Wno-cpp
build/__native.c:37:32: error: use of undeclared identifier 'NormDict_finalize'
    .tp_finalize = (destructor)NormDict_finalize,
                               ^
1 error generated.
error: command '/usr/bin/clang' failed with exit code 1

[mr-c]

I did a git bisect using the following script and @JelleZijlstra 's minimal reproducer

#!/bin/bash
python -m pip install -e .
rm -Rf build .mypy_cache mypyc_crash.*.so
python -m mypyc mypyc_crash.py

Which found 8104d01 from #18519 matching the previous suggestion by @JelleZijlstra .

@advait-dixit can you take a look at this?

[advait-dixit]

Yes, I can take a look at this and report back on Monday.