Bug report

I built both CPython checkouts with:

CC=clang CXX=clang++ LDFLAGS='-fuse-ld=lld' ./configure --with-tail-call-interp --enable-experimental-jit=yes --with-pydebug --with-address-sanitizer --with-undefined-behavior-sanitizer

./python -VV:

• 3.15: Python 3.15.0rc3+dev (heads/3.15:874d1122deb, Oct 7 2026, 14:48:22) [Clang 23.1.1 ]
• main: Python 3.16.0a0 (heads/main:37cc8dd0b9a, Oct 7 2026, 14:51:35) [Clang 23.1.1 ]

From a SQLAlchemy checkout, I ran:

uv sync --all-extras --all-groups --all-packages --python /home/boss/projects/oss/cpython/3.15/python
uv sync --all-extras --all-groups --all-packages --python /home/boss/projects/oss/cpython/main/python

On 3.15, setuptools.build_meta.prepare_metadata_for_build_editable created the metadata, then LeakSanitizer reported 852 bytes leaked in 6 allocations. On main, setuptools.build_meta.build_editable created the wheel, then LeakSanitizer reported 703 bytes leaked in 6 allocations. Both builds exited with status 1, so uv sync failed.

Relevant excerpt from the main run (not the full log):

==254631==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 264 byte(s) in 1 object(s) allocated from:
    #0 0x55eb6fe15b81 in malloc (/home/boss/projects/oss/cpython/main/python+0xf66b81)
    #1 0x55eb703eaa37 in _PyMem_DebugRawAlloc /home/boss/projects/oss/cpython/main/Objects/obmalloc.c:3103:24
    #2 0x55eb70392647 in _PyObject_NewVar /home/boss/projects/oss/cpython/main/Objects/object.c:570:26
    #3 0x55eb701df82c in _PyCode_New /home/boss/projects/oss/cpython/main/Objects/codeobject.c:734:10
    #4 0x55eb70b941d8 in r_object /home/boss/projects/oss/cpython/main/Python/marshal.c:1734:29

SUMMARY: AddressSanitizer: 703 byte(s) leaked in 6 allocation(s).

Expected: the build process exits without a LeakSanitizer error.

CPython versions tested on:

3.15, 3.16, CPython main branch

Operating systems tested on:

Linux