Fix a race condition where a thread could receive a partially-initialized
module when another thread's import fails. The race occurs when:
1. Thread 1 starts importing, adds module to sys.modules
2. Thread 2 sees the module in sys.modules via the fast path
3. Thread 1's import fails, removes module from sys.modules
4. Thread 2 returns a stale module reference not in sys.modules
The fix adds verification after the "skip lock" optimization in both Python
and C code paths to check if the module is still in sys.modules. If the
module was removed (due to import failure), we retry the import so the
caller receives the actual exception from the import failure rather than
a stale module reference.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Changing the values requires forking and patching, which is intentional. Simply rebuilding from source does not change the implementation enough to justify changing these values - they would still be `cpython` and compatible with existing `.pyc` files. But people who maintain forks are better served by being able to easily override these values in a place that can be forward-ported reliably.
* Reapply "gh-132947: Apply changes from importlib_metadata 8.7 (#137885)" (#137924)
This reverts commit 3706ef66ef.
* Skip the triggering test on buildbots only.
* Sync with importlib_metadata 8.2.0
Removes deprecated behaviors, including support for `PackageMetadata.__getitem__` returning None for missing keys and Distribution subclasses not implementing abstract methods.
Prioritizes valid dists to invalid dists when retrieving by name (python/cpython/#120492). Adds SimplePath to `importlib.metadata.__all__`.
* Add blurb
Enough other classes in `importlib.abc` inherit from the class and the deprecation was to redirect people to `TraversableResources`. The documentation now makes it clear the class only exists for backwards compatibility.
---------
Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
Optimize `LOAD_FAST` opcodes into faster versions that load borrowed references onto the operand stack when we can prove that the lifetime of the local outlives the lifetime of the temporary that is loaded onto the stack.
Ignore PermissionError when checking cwd during import
On macOS `getcwd(3)` can return EACCES if a path component isn't readable,
resulting in PermissionError. `PathFinder.find_spec()` now catches these and
ignores them - the same treatment as a missing/deleted cwd.
Introduces `test.support.os_helper.save_mode(path, ...)`, a context manager
that restores the mode of a path on exit.
This is allows finer control of exception handling and robust environment
restoration across platforms in `FinderTests.test_permission_error_cwd()`.
Co-authored-by: Jason R. Coombs <jaraco@jaraco.com>
Co-authored-by: Brett Cannon <brett@python.org>
Add the following methods:
* assertHasAttr() and assertNotHasAttr()
* assertIsSubclass() and assertNotIsSubclass()
* assertStartsWith() and assertNotStartsWith()
* assertEndsWith() and assertNotEndsWith()
Also improve error messages for assertIsInstance() and
assertNotIsInstance().
* gh-116608: Apply style and compatibility changes from importlib_metadata.
* gh-121735: Ensure module-adjacent resources are loadable from a zipfile.
* gh-121735: Allow all modules to be processed by the ZipReader.
* Add blurb
* Remove update-zips script, unneeded.
* Remove unnecessary references to removed static fixtures.
* Remove zipdata fixtures, unused.
Add __all__ to the following modules:
importlib.machinery, importlib.util and xml.sax.
Add also "# noqa: F401" in collections.abc,
subprocess and xml.sax.
* Sort __all__; remove collections.abc.__all__; remove private names
* Add tests
`drop_gil()` assumes that its caller is attached, which means that the current
thread holds the GIL if and only if the GIL is enabled, and the enabled-state
of the GIL won't change. This isn't true, though, because `detach_thread()`
calls `_PyEval_ReleaseLock()` after detaching and
`_PyThreadState_DeleteCurrent()` calls it after removing the current thread
from consideration for stop-the-world requests (effectively detaching it).
Fix this by remembering whether or not a thread acquired the GIL when it last
attached, in `PyThreadState._status.holds_gil`, and check this in `drop_gil()`
instead of `gil->enabled`.
This fixes a crash in `test_multiprocessing_pool_circular_import()`, so I've
reenabled it.
The `pool_in_threads.py` test file may crash in free-threaded builds,
which can lead to the Tsan test hanging. Skip it for now until we fix
the underlying issue.
