gh-146450: Ensure Android gradle build uses custom cross-build dir (#148319)
Ensures that the testbed's Gradle configuration uses the cross-build environment
variable, and that variable is passed to Gradle by the cross-build script.
Gregory P. Smith [Sun, 12 Apr 2026 06:06:19 +0000 (23:06 -0700)]
gh-146313: Fix multiprocessing ResourceTracker deadlock after os.fork() (GH-146316)
`ResourceTracker.__del__` (added in gh-88887 circa Python 3.12) calls
os.waitpid(pid, 0) which blocks indefinitely if a process created via os.fork()
still holds the tracker pipe's write end. The tracker never sees EOF, never
exits, and the parent hangs at interpreter shutdown.
Fix with two layers:
- **At-fork handler.** An os.register_at_fork(after_in_child=...)
handler closes the inherited pipe fd in the child unless a preserve
flag is set. popen_fork.Popen._launch() sets the flag before its
fork so mp.Process(fork) children keep the fd and reuse the parent's
tracker (preserving gh-80849). Raw os.fork() children close the fd,
letting the parent reap promptly.
- **Timeout safety-net.** _stop_locked() gains a wait_timeout
parameter. When called from `__del__`, it polls with WNOHANG using
exponential backoff for up to 1 second instead of blocking
indefinitely. The at-fork handler makes this unreachable in
well-behaved paths; it remains for abnormal shutdowns.
Chris Eibl [Sun, 12 Apr 2026 05:49:18 +0000 (07:49 +0200)]
GH-148047: Check early whether tail-calling is possible for MSVC builds on Windows (#148036)
Rather than failing late when compiling e.g. a debug configuration
```
build.bat -c debug --tail-call-interp
```
with hundreds of
```
error C4737: Unable to perform required tail call. Performance may be degraded.
```
-- fail early with an explicit error message for configurations that are not supported by MSVC.
This is a follow-up on https://github.com/python/cpython/issues/140513 / https://github.com/python/cpython/pull/140548
gh-89520: Load extension settings and keybindings from user config (GH-28713)
Extension keybindings defined in ~/.idlerc/config-extensions.cfg were silently ignored because GetExtensionKeys, __GetRawExtensionKeys, and GetExtensionBindings only checked default config. Fix these to check user config as well, and update the extensions config dialog to handle user-only extensions correctly.
---------
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com> Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com> Co-authored-by: Gregory P. Smith <68491+gpshead@users.noreply.github.com> Co-authored-by: Gregory P. Smith <greg@krypto.org>
gh-147965: Add shutdown() to multiprocessing.Queue excluded methods (GH-147970)
The multiprocessing.Queue documentation states it implements all
methods of queue.Queue except task_done() and join(). Since
queue.Queue.shutdown() was added in Python 3.13,
multiprocessing.Queue also does not implement it. Update the docs
to include shutdown() in the list of excluded methods.
gh-142831: Fix use-after-free in json encoder during re-entrant mutation (gh-142851)
Hold strong references to borrowed items unconditionally (not only in
free-threading builds) in _encoder_iterate_mapping_lock_held and
_encoder_iterate_fast_seq_lock_held. User callbacks invoked during
encoding can mutate or clear the underlying container, invalidating
borrowed references.
The dict iteration path was already fixed by gh-145244.
Co-authored-by: Kumar Aditya <kumaraditya@python.org> Co-authored-by: Gregory P. Smith <greg@krypto.org>
Gregory P. Smith [Sun, 12 Apr 2026 00:02:56 +0000 (17:02 -0700)]
gh-146287: Fix signed/unsigned mismatch in _hashlib_hmac_digest_size (GH-148407)
* gh-146287: use signed type for HMAC digest size to prevent unsigned wrapping
Change _hashlib_hmac_digest_size() return type from unsigned int to int
so that a hypothetical negative return from EVP_MD_size() is not
silently wrapped to a large positive value. Add an explicit check for
negative digest_size in the legacy OpenSSL path, and use SystemError
(not ValueError) since these conditions indicate internal invariant
violations. Also add debug-build asserts to EVP_get_block_size and
EVP_get_digest_size documenting that the hash context is always
initialized.
gh-145244: Fix use-after-free on borrowed dict key in json encoder (GH-145245)
In encoder_encode_key_value(), key is a borrowed reference from
PyDict_Next(). If the default callback mutates or clears the dict,
key becomes a dangling pointer. The error path then calls
_PyErr_FormatNote("%R", key) on freed memory.
Fix by holding strong references to key and value unconditionally
during encoding, not just in the free-threading build.
Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
gh-145105: Fix crash in csv.reader with re-entrant iterator (GH-145106)
When a custom iterator calls next() on the same csv.reader from
within __next__, the inner iteration sets self->fields to NULL.
The outer iteration then crashes in parse_save_field() by passing
NULL to PyList_Append.
Add a guard after PyIter_Next() to detect that fields was set to
NULL by a re-entrant call, and raise csv.Error instead of crashing.
Gregory P. Smith [Sat, 11 Apr 2026 21:54:23 +0000 (14:54 -0700)]
gh-146302: make Py_IsInitialized() thread-safe and reflect true init completion (GH-146303)
## Summary
- Move the `runtime->initialized = 1` store from before `site.py` import to the end of `init_interp_main()`, so `Py_IsInitialized()` only returns true after initialization has fully completed
- Access `initialized` and `core_initialized` through new inline accessors using acquire/release atomics, to also protect from data race undefined behavior
- `PySys_AddAuditHook()` now uses the accessor, so with the flag move it correctly skips audit hook invocation during all init phases (matching the documented "after runtime initialization" behavior) ... We could argue that running these earlier would be good even if the intent was never explicitly expressed, but that'd be its own issue.
## Motivation
`Py_IsInitialized()` returned 1 while `Py_InitializeEx()` was still running — specifically, before `site.py` had been imported. See https://github.com/PyO3/pyo3/issues/5900 where a second thread could acquire the GIL and start executing Python with an incomplete `sys.path` because `site.py` hadn't finished.
The flag was also a plain `int` with no atomic operations, making concurrent reads a C-standard data race, though unlikely to manifest.
## Regression test:
The added test properly fails on `main` with `ERROR: Py_IsInitialized() was true during site import`.
---
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Petr Viktorin [Wed, 8 Apr 2026 07:15:11 +0000 (09:15 +0200)]
gh-145921: Add "_DuringGC" functions for tp_traverse (GH-145925)
There are newly documented restrictions on tp_traverse:
The traversal function must not have any side effects.
It must not modify the reference counts of any Python
objects nor create or destroy any Python objects.
* Add several functions that are guaranteed side-effect-free,
with a _DuringGC suffix.
* Use these in ctypes
* Consolidate tp_traverse docs in gcsupport.rst, moving unique
content from typeobj.rst there
Co-authored-by: Lysandros Nikolaou <lisandrosnik@gmail.com> Co-authored-by: Victor Stinner <vstinner@python.org>
gh-145846: Fix memory leak in _lsprof clearEntries() context chain (#145847)
clearEntries() only freed the top currentProfilerContext but did not
walk the previous linked list. When clear() is called during active
profiling with nested calls, all contexts except the top one were
leaked. Fix by iterating the entire linked list, matching the existing
freelistProfilerContext cleanup pattern.
Co-authored-by: Victor Stinner <vstinner@python.org>
gh-146333: Fix quadratic regex backtracking in configparser option parsing (GH-146399)
Use negative lookahead in option regex to prevent backtracking, and to avoid changing logic outside the regexes (since people could use the regex directly).
Petr Viktorin [Tue, 7 Apr 2026 07:06:17 +0000 (09:06 +0200)]
gh-146636: abi3t: Define Py_GIL_DISABLED but do not use it (GH-148142)
When compiling for abi3t, define Py_GIL_DISABLED, so that users who
check it to enable additional locking aren't broken.
But also avoid using Py_GIL_DISABLED in Python headers themselves
-- abi3 and abi3t ought to be the same except
the _Py_OPAQUE_PYOBJECT differences.
A check for this is coming in a later PR.
It will require rewriting some preprocessor conditions, some of these
changes are included in this PR.
For _Py_IsOwnedByCurrentThread & supporting functions
I opted to move them to a cpython/ header, as they're rather self-contained.
gh-144503: Pass sys.argv to forkserver as real argv elements (GH-148194)
Avoid embedding the parent's sys.argv into the forkserver -c command
string via repr(). When sys.argv is large (e.g. thousands of file
paths from a pre-commit hook), the resulting single argument could
exceed the OS per-argument length limit (MAX_ARG_STRLEN on Linux,
typically 128 KiB), causing posix_spawn to fail and the parent to
observe a BrokenPipeError.
Instead, append the argv entries as separate command-line arguments
after -c; the forkserver child reads them back as sys.argv[1:]. This
cannot exceed any limit the parent itself did not already satisfy.
projects / thirdparty / Python / cpython.git / log
