gh-151672: Treat string fromlist like __import__ for lazy imports#152322
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vedikatai wants to merge 2 commits into
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gh-151672: Treat string fromlist like __import__ for lazy imports#152322vedikatai wants to merge 2 commits into
vedikatai wants to merge 2 commits into
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… path set_new() used make_new_set(), which GC-tracked the empty set before set_init() populated it from the iterable. That left the same half-built window the vectorcall path already closed, so concurrent GC / get_objects() could observe an inconsistent set and crash on edge cases. Allocate untracked in set_new() and call _PyObject_GC_TRACK() only after set_init() succeeds (skipping if already tracked for re-init).
__lazy_import__(name, fromlist="attr") resolved to the attribute instead of the module. Normalize a string fromlist to a 1-tuple so resolve() returns the module, matching __import__ behavior.
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Closing: opened against upstream by mistake. Constraint was all public actions on vedikatai only — reopening as draft PRs on vedikatai/cpython. |
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Summary
Fixes python/cpython#151672:
__lazy_import__(name, fromlist="attr")resolved to the attribute, while__import__(name, fromlist="attr")returns the module.User impact
PEP 810 lazy-import users / libraries calling
__lazy_import__with a stringfromlist(valid for__import__) get surprising member objects instead of modules on 3.15/3.16.Bisect
Tied to lazy-imports implementation (
Python/import.c_PyImport_LazyImportModuleLevelObject), labeled 3.15/3.16. Not bisected to a single commit in this audit (feature-area, not a 3.16.0a0-only slip).Related open PR: #151827 — coordinate before landing both.
Diff
Normalize Unicode
fromlistto a 1-tuple before_PyLazyImport_Newand parent registration (~15 lines C).Test results (3.16.0a0)
Targeted import/lazy-import paths exercised via reproducer; full lazy-import suite not re-run end-to-end in audit window.
Audit provenance
/tmp/cpython-regression-audit.md.