Memory leak in test_capi with subinterpreter creation

[ashm-dev]

Bug report

Bug description:

LeakSanitizer detects memory leaks when running test_capi with refleak detection. The leaks occur during subinterpreter creation via Py_NewInterpreterFromConfig().

Affected Versions

• Python 3.12
• Python 3.13
• Python 3.14
• CPython main branch

Steps to Reproduce

1. Build CPython with AddressSanitizer and debug mode:

CC=clang CXX=clang++ ./configure --with-address-sanitizer --with-pydebug --with-undefined-behavior-sanitizer --disable-optimizations && make -j$(nproc)

2. Run test_capi with refleak detection:

./python -X dev -X showrefcount -m test -R 5:5 test_capi -j$(nproc)

Logs

312.log
313.log
314.log
main.log

CPython versions tested on:

3.15, CPython main branch, 3.14, 3.13, 3.12

Operating systems tested on:

Linux

Linked PRs

• gh-140301: Fix memory leak in subinterpreter PyConfig cleanup #140303
• [3.14] gh-140301: Fix memory leak in subinterpreter PyConfig cleanup (GH-140303) #140360

[ZeroIntensity]

In the future, would you mind including locations (preferably a GitHub source link) in your reports? It's extra work for us when you just drop large log files.

[ashm-dev]

Sure, I'll include GitHub source links in future reports. Thanks for the feedback!

[ashm-dev]

I'll take a shot at fixing this, but no promises :)