[WIP: FIX] python 3.15.0rc2 (host/run + PREFIX/lib)

[skupr-anaconda]

Destination channel: ad-testing/label/py315

Links

• Jira
• Upstream repository
• Predecessor: python 3.15.0rc2: split libpython shared output #259

Explanation of changes:

• Same C16+C17 libpython split as python 3.15.0rc2: split libpython shared output #259, plus Charles's follow-ups (pipefail, stricter prefix-replacement NEEDED check, osx PGO dylib link, anaconda.yaml libpython).
• mkdir -p ${PREFIX}/lib before copying shared libs in install_shared.sh.
• libpython: pin_subpackage('python') stays on build; host: [] and run: [] (no host/run cycle).
• python-freethreading / python-gil / python-jit use explicit run: keys.

Notes:

• Replacement for python 3.15.0rc2: split libpython shared output #259 (do not merge both). Human merge only.
• Do not publish 3.15 to pkgs/main (PKG-15601 PBC).
• linux-64 FT fail on python 3.15.0rc2: split libpython shared output #259 graph 07ffe00c was HTTP 403 on pkgs/main (infra), not this delta.

[skupr-anaconda]

Reviewer notes: purpose + staging artifact layout

Inspected graph 31575e93 (07e8e80) and staging pbp/fs/python-feedstock/pr261/07e8e80. File lists below are from the .conda payloads (GIL _101_cp315 unless noted).

What this PR is for

Split the Unix shared library out of python into a new libpython output (CF C16/C17 / #259), so:

• python = interpreter + stdlib + headers + extension modules. No libpython*.so / .dylib.
• libpython = shared lib for embedders (GDB, etc.). host: [] / run: [] — no cycle with python. Weak run_exports: libpython >=3.15.0rc2,<4.0a0.
• libpython-static = .a / .nolto.a only (unix install script). Exact pin on matching python.
• Win: libpython is skipped; the DLLs stay in python. libpython-static still publishes but is empty.

The interpreter does not NEEDED libpython. Linking extensions to libpython is redundant on Linux and harmful on Darwin (multiply-defined symbols). Prefix-replacement tests now distinguish libpython (must NEEDED the shared lib) vs libpython-static (must not).

Dest: ad-testing/label/py315. Do not merge with #259. Do not ship 3.15 to pkgs/main.

Graph (this SHA)

50 completed / 3 failed. Two linux-64 tests (libpython-static, python-jit) died on repo.anaconda.com HTTP 429 / conda-client registration after the solver succeeded — infra, not this split. One linter task also failed.

Staging matrix (3.15.0rc2)

subdir	python	libpython	libpython-static	notes
linux-64, linux-aarch64, osx-arm64	GIL + FT	GIL + FT	GIL + FT
win-64	GIL + FT	— skipped	empty (0 files)	DLLs inside python
osx-64, win-arm64	—	—	—	empty indexes
noarch	—	—	—	python-gil, python-freethreading, python-jit (__unix / __win)

libpython (new)

linux-64 GIL (hb63ce8a_101_cp315, ~12 MB .conda):

lib/libpython3.15.so.1.0    ~40 MB  SONAME libpython3.15.so.1.0  RPATH $ORIGIN/.
lib/libpython3.15.so        → libpython3.15.so.1.0
lib/libpython3.so           ~15 KB  stub, NEEDED libpython3.15.so.1.0

linux-64 FT: libpython3.15t.so{,.1.0} + libpython3.so.
osx-arm64 GIL: lib/libpython3.15.dylib + lib/libpython3.dylib only (no .1.0).

python

Does not contain libpython*. Does not depend on libpython.
run_exports: python_abi 3.15.* *_cp315 (FT: *_cp315t + track_features: free-threading). Frozen AR: tk 9.0.4, openssl 3.5.8, glibc 2.28, PSF-2.0.

linux-64 GIL (h67b78d7_101_cp315, 2814 files):

• bin/{python,python3,python3.15,python3.15-config,python3-config,idle3,idle3.15,pydoc,pydoc3,pydoc3.15}
• include/ (296), lib/python3.15/ (791 .py + 1555 .pyc + 76 lib-dynload/*.so)
• compiler_compat/{ld,README}, manpages
• Interpreter: PIE ELF, NEEDED pthread/dl/util/m/gcc_s/libc only, RPATH $ORIGIN/../lib, not stripped (debug_info)

linux-64 FT: same under lib/python3.15t/, extra bin/python3.15t{,-config}.

win-64 GIL (2013 files): python.exe / pythonw.exe / python3.dll / python315.dll (+ pdbs), libs/python3.lib + python315.lib, 37 .pyd in lib/python/lib-dynload/ (no DLLs/).

libpython-static

linux-64 GIL: lib/libpython3.15.a, lib/libpython3.15.nolto.a, lib/python3.15/config-3.15-x86_64-linux-gnu/libpython3.15.a (~387 MB payload).
win-64: 0 files (unix-only install_static.sh; empty artifact still published).

Noarch

package	files	role
python-gil	0	metapackage: python 3.15.0rc2.* + python_abi * *_cp315
python-freethreading	0	same + *_cp315t
python-jit unix	2	activate/deactivate → PYTHON_JIT=1
python-jit win	4	same + .bat

Bottom line for review

Layout matches the intended CF-style split. Shared lib is out of python and into libpython on Unix. Empty win libpython (skipped) / empty win libpython-static / empty ABI metapackages are by recipe. Remaining CI red is the 429 on two tests, not missing files in libpython.