[3.14] gh-135676: Reword the f-string (and t-string) section (GH-137469) (GH-142227)
Much of the information was duplicated in stdtypes.rst; this PR keeps
lexical/syntactical details in Lexical Analysis and the evaluation & runtime
behaviour in Standard types, with cross-references between the two.
Since the t-string section only listed differences from f-strings, and the
grammar for the two is equivalent, that section was moved to Standard types
almost entirely.
(cherry picked from commit aea5531583aaa8bfdf3ebca914e9c694617c3489)
Co-authored-by: Petr Viktorin <encukou@gmail.com> Co-authored-by: Blaise Pabon <blaise@gmail.com> Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com> Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com>
[3.14] Being more flexible in when not to explicitly set the sysroot when compiling for WASI (GH-142242) (GH-142246)
Being more flexible in when not to explicitly set the sysroot when compiling for WASI (GH-142242)
(cherry picked from commit c5252045d3a7164f1829503d122091b5e469fda3)
This fixes a regression introduced in gh-140558. The interpreter would
crash if we inserted a non `str` key into a split table that matches an
existing key.
(cherry picked from commit 547d8daf780646e2800bec598ed32085817c8606)
Stan Ulbrych [Wed, 3 Dec 2025 12:43:06 +0000 (12:43 +0000)]
[3.14] gh-135676: Simplify docs on lexing names (GH-140464) (GH-142015)
This simplifies the Lexical Analysis section on Names (but keeps it technically correct) by putting all the info about non-ASCII characters in a separate (and very technical) section.
It uses a mental model where the parser doesn't handle Unicode complexity “immediately”, but:
- parses any non-ASCII character (outside strings/comments) as part of a name, since these can't (yet) be e.g. operators
- normalizes the name
- validates the name, using the xid_start/xid_continue sets
[3.14] gh-59000: Fix pdb breakpoint resolution for class methods when module not imported (GH-141949) (#142171)
gh-59000: Fix pdb breakpoint resolution for class methods when module not imported (GH-141949)
(cherry picked from commit 5e58548ebe8f7ac8c6cb0bad775912caa4090515)
The GC for the free threaded build would get slower with each collection due
to effectively double counting objects freed by the GC.
(cherry picked from commit eb892868b31322d7cf271bc25923e14b1f67ae38)
[3.14] gh-119342: Fix a potential denial of service in plistlib (GH-119343) (GH-142143)
Reading a specially prepared small Plist file could cause OOM because file's
read(n) preallocates a bytes object for reading the specified amount of
data. Now plistlib reads large data by chunks, therefore the upper limit of
consumed memory is proportional to the size of the input file.
(cherry picked from commit 694922cf40aa3a28f898b5f5ee08b71b4922df70)
[3.14] gh-119452: Fix a potential virtual memory allocation denial of service in http.server (GH-119455)
The CGI server on Windows could consume the amount of memory specified
in the Content-Length header of the request even if the client does not
send such much data. Now it reads the POST request body by chunks,
so that the memory consumption is proportional to the amount of sent
data.
[3.14] GH-91636: Clear weakrefs created by finalizers. (GH-136401) (#141993)
GH-91636: Clear weakrefs created by finalizers. (GH-136401)
Weakrefs to unreachable garbage that are created during running of
finalizers need to be cleared. This avoids exposing objects that
have `tp_clear` called on them to Python-level code.
(cherry picked from commit b6b99bf7f1edab77c485faf4e23da868f3a7b68c)
Co-authored-by: Neil Schemenauer <nas-github@arctrix.com>
[3.14] gh-87512: Fix `subprocess` using `timeout=` on Windows blocking with a large `input=` (GH-142058) (#142068)
gh-87512: Fix `subprocess` using `timeout=` on Windows blocking with a large `input=` (GH-142058)
On Windows, Popen._communicate() previously wrote to stdin synchronously, which could block indefinitely if the subprocess didn't consume input= quickly and the pipe buffer filled up. The timeout= parameter was only checked when joining the reader threads, not during the stdin write.
This change moves the Windows stdin writing to a background thread (similar to how stdout/stderr are read in threads), allowing the timeout to be properly enforced. If timeout expires, TimeoutExpired is raised promptly and the writer thread continues in the background. Subsequent calls to communicate() will join the existing writer thread.
Adds test_communicate_timeout_large_input to verify that TimeoutExpired is raised promptly when communicate() is called with large input and a timeout, even when the subprocess doesn't consume stdin quickly.
This test already passed on POSIX (where select() is used) but failed on Windows where the stdin write blocks without checking the timeout.
(cherry picked from commit 5b1862bdd8021b5295df95d730c2d2efa827fa88)
Co-authored-by: Gregory P. Smith <68491+gpshead@users.noreply.github.com> Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
[3.14] gh-141473: Fix subprocess.Popen.communicate to send input to stdin upon a subsequent post-timeout call (GH-141477) (#142059)
gh-141473: Fix subprocess.Popen.communicate to send input to stdin upon a subsequent post-timeout call (GH-141477)
* gh-141473: Fix subprocess.Popen.communicate to send input to stdin
* Docs: Clarify that `input` is one time only on `communicate()`
* NEWS entry
* Add a regression test.
GH-134453: Fix subprocess memoryview input handling on POSIX (GH-134949)
Fix inconsistent subprocess.Popen.communicate() behavior between Windows
and POSIX when using memoryview objects with non-byte elements as input.
On POSIX systems, the code was incorrectly comparing bytes written against
element count instead of byte count, causing data truncation for large
inputs with non-byte element types.
Changes:
- Cast memoryview inputs to byte view when input is already a memoryview
- Fix progress tracking to use len(input_view) instead of len(self._input)
- Add comprehensive test coverage for memoryview inputs
🤖 Generated with [Claude Code](https://claude.ai/code)
* old-man-yells-at-ReST
* Update 2025-05-30-18-37-44.gh-issue-134453.kxkA-o.rst
* assertIsNone review feedback
* fix memoryview_nonbytes test to fail without our fix on main, and have a nicer error.
[3.14] gh-116738: Fix thread-safety issue in re module for free threading (gh-141923) (gh-141990)
Added atomic operations to `scanner_begin()` and `scanner_end()` to prevent
race conditions on the `executing` flag in free-threaded builds. Also added
tests for concurrent usage of the `re` module.
Without the atomic operations, `test_scanner_concurrent_access()` triggers
`assert(self->executing)` failures, or a thread sanitizer run emits errors.
(cherry picked from commit bc9e63dd9d2931771415cca1b0ed774471d523c0)
Petr Viktorin [Wed, 26 Nov 2025 11:54:56 +0000 (12:54 +0100)]
[3.14] GH-139653: Only raise an exception (or fatal error) when the stack pointer is about to overflow the stack. (GH-141711) (GH-141944)
Only raises if the stack pointer is both below the limit *and* above the stack base.
This prevents false positives for user-space threads, as the stack pointer will be outside those bounds
if the stack has been swapped.
Co-authored-by: Rok Mandeljc <rok.mandeljc@gmail.com> Co-authored-by: Mark Shannon <mark@hotpy.org> Co-authored-by: Victor Stinner <vstinner@python.org>
[3.14] gh-141907: Better handle support for SHA3 for test_hashlib (GH-141908) (#141918)
gh-141907: Better handle support for SHA3 for test_hashlib (GH-141908)
* test_hashlib: better handle support for SHA3
It's possible that the SSL library supports only SHA3 algo and doesn't
have SHAKE one.
The current test wrongly detect this and set both HASH and HASHXOF to
None expecting to have the extra SHA3 attributes present but this should
only be true for SHAKE algo.
To better handle this, move the HASH condition to a dedicated try-expect
condition and check if HASHXOF is None in the relevant code effectively
checking if SHA3 is supported by the SSL library but SHAKE algo needs to
use the sha3module one.
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> Co-authored-by: Christian Marangi <ansuelsmth@gmail.com> Co-authored-by: Gregory P. Smith <greg@krypto.org>
Co-authored-by: Peter Bierma <zintensitydev@gmail.com> Co-authored-by: Stan Ulbrych <stan@ulbrych.org> Co-authored-by: Victor Stinner <vstinner@python.org>
[3.14] gh-129441: Fix some flakiness in test_instrumentation (gh-141881) (gh-141913)
Most of the `self.assertTrue(self.called)` checks are flaky because
the worker threads may sometimes finish before the main thread calls
`self.during_threads()`.
(cherry picked from commit 71126ab19c76d8227fc3b9c7c59b957ca82af4dd)
[3.14] gh-106318: Add example for str.isascii() (GH-137558) (#141898)
Co-authored-by: Adorilson Bezerra <adorilson@gmail.com> Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com> Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
[3.14] gh-135335: Simplify preload regression test using __main__ (GH-138686) (#141886)
gh-135335: Simplify preload regression test using __main__ (GH-138686)
Simplify preload regression test using `__main__`
With the fix for gh-126631 `__main__` modules can be preloaded and the regression
test for gh-135335 can be simplified to just use a self-contained script rather
than requiring a module.
[3.14] gh-120158: Fix inconsistent monitoring state when setting events too frequently (gh-141845) (gh-141879)
If we overflowed the global version counter (i.e., after 2*24 calls to
`_PyMonitoring_SetEvents`), we bailed out after setting global monitoring
events but before instrumenting code objects, which led to assertion errors
later on.
Also add a `time.sleep()` to `test_free_threading.test_monitoring` to avoid
overflowing the global version counter.
(cherry picked from commit e457d60daafe66534283e0f79c81517634408e57)
[3.14] gh-141801: Use accessors for ASN1_STRING fields in libssl (GH-141802) (#141847)
gh-141801: Use accessors for ASN1_STRING fields in libssl (GH-141802)
* gh-141801: Use accessors for ASN1_STRING fields
While ASN1_STRING is currently exposed, it is better to use the
accessors. See https://github.com/openssl/openssl/issues/29117 where, if
the type were opaque, OpenSSL's X509 objects could be much more
memory-efficient.
[3.14] gh-116738: Make csv module thread-safe (gh-141365) (gh-141825)
Added a critical section to protect the states of `ReaderObj` and `WriterObj` in the free-threading build. Without the critical sections, both new free-threading tests were crashing.
(cherry picked from commit fb26d9c2ef739cbfdc134da5ab89470511f1f5fd)
Co-authored-by: Peter Bierma <zintensitydev@gmail.com> Co-authored-by: Stan Ulbrych <89152624+StanFromIreland@users.noreply.github.com> Co-authored-by: Victor Stinner <vstinner@python.org>
The dataclasses `__init__` function is generated dynamically by a call to `exec()` and so doesn't have deferred reference counting enabled. Enable deferred reference counting on functions when assigned as an attribute to type objects to avoid reference count contention when creating dataclass instances.
(cherry picked from commit ce791541769a41beabec0f515cd62e504d46ff1c)
[3.14] gh-141570: can_colorize: Expect fileno() to raise OSError, as documented (GH-141716) (#141747)
gh-141570: can_colorize: Expect fileno() to raise OSError, as documented (GH-141716)
In Fedora, we've been given a slightly incomplete reproducer for a problematic
Python 3.14 color-related change in argparse that leads to an exception when
Python is used from mod_wsgi: https://bugzilla.redhat.com/2414940
mod_wsgi replaces sys.stdout with a custom object that raises OSError on .fileno():
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