When a custom `closed` property on the underlying buffer calls
`detach()` during the `file_closed()` check in `close()`, the
wrapper's internal buffer becomes None. Subsequent flush/close
operations then fail with AttributeError on NoneType.
Add a guard after the `file_closed()` check to detect if the buffer
was detached reentrantly, and return early in that case (detach has
already flushed the stream).
This mirrors the fix applied in CPython
(https://github.com/python/cpython/issues/142594\).
* rewrite finalize_modules with phased algorithm
Replace the absence of module finalization during interpreter shutdown
with a 5-phase algorithm matching pylifecycle.c finalize_modules():
1. Set special sys attributes to None, restore stdio
2. Set all sys.modules values to None, collect module dicts
3. Clear sys.modules dict
4. Clear module dicts in reverse import order (2-pass _PyModule_ClearDict)
5. Clear sys and builtins dicts last
This ensures __del__ methods are called during shutdown and modules are
cleaned up in reverse import order without hardcoded module names.
* dealloc the rigth way
* fix finalize_modules: only clear __main__ dict, mark daemon thread tests as expected failure
Without GC, clearing all module dicts during finalization causes __del__
handlers to fail (globals are None). Restrict Phase 4 to only clear
__main__ dict — other modules' globals stay intact for their __del__
handlers.
Mark test_daemon_threads_shutdown_{stdout,stderr}_deadlock as expected
failures — without GC+GIL, finalize_modules clears __main__ globals
while daemon threads are still running.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>
* Downgraded skips in tests
* Fixed failing tests
* Fixed test_ftplib + test_socket + test_ssl + test_threaded_import failures
* Removed comments about which tests are run in which environment
* Addressed PR comments
* Annotated skips on failing tests
* Removed unneeded tests
* Removed unneeded sys import from test_ftplib
* Added annotation to test_ftplib
* Readded skipIf to test_cleanup_with_symlink_modes with a more general ENV_POLLUTING_TESTS_WINDOWS
* Addressed PR comments
* Made changes to minimize diff in PR
* Apply suggestion from @youknowone
---------
Co-authored-by: Jeong, YunWon <69878+youknowone@users.noreply.github.com>
Initially this is only meant to be a small update for `test_io.py`.
But it turns out that `test.support` need a lot of cleanup especially
for `test.support.warnings_helper`.
