Make _find_and_load() acquire the module locks for the full
dotted-name chain (parent before child) when loading a nested module, so
both threads contend on the same first lock and serialise instead of
deadlocking.
When acquiring a parent's lock would itself deadlock with another thread
that is loading that parent (cross-package circular imports), the parent's
lock is skipped and the partially-initialised parent is accepted -- the
same policy _lock_unlock_module() already applies on the existing code
path -- so concurrent circular imports that worked before continue to work.
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>
Many functions related to compiling or parsing Python code, such as
compile(), ast.parse(), symtable.symtable(),
and importlib.abc.InspectLoader.source_to_code() now allow to pass
the module name used when filtering syntax warnings.
* 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>
Entries may be added or removed from `sys.meta_path` concurrently. For
example, setuptools temporarily adds and removes the `distutils` finder from
the beginning of the list. The local copy ensures that we don't skip over any
entries.
Some packages modify `sys.modules` during import. For example, `collections`
inserts the entry for `collections.abc` into `sys.modules` during import. We
need to ensure that we re-check `sys.modules` *after* the parent module is
fully initialized.
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>
* 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.
As of 529a160 (gh-118204), building with HAVE_DYNAMIC_LOADING stopped working. This is a minimal fix just to get builds working again. There are actually a number of long-standing deficiencies with HAVE_DYNAMIC_LOADING builds that need to be resolved separately.
Gregory P. Smith