Fix SharedMemoryArray.__del__ AttributeError during interpreter shutdown - #1386
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Fix SharedMemoryArray.__del__ AttributeError during interpreter shutdown#1386rootkiller6788 wants to merge 1 commit into
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During interpreter shutdown, module-level names in shared_memory_array.py (such as mmap and shared_memory) may be set to None. The __del__ method referenced these globals directly, so a lingering SharedMemoryArray raised AttributeError: 'NoneType' object has no attribute 'mmap' at shutdown, cluttering logs (issue google#398). Bind the mmap.mmap and shared_memory.SharedMemory types and the _del_shm helper as default arguments (bound at import time), and access the class attributes via type(self), so __del__ no longer depends on module globals. Adds a regression test that clears the relevant module globals and verifies deletion still unlinks the shared memory block.
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Problem
At interpreter shutdown,
SharedMemoryArray.__del__can raise:This is reported in #398 and clutters shutdown logs in data pipelines that use shared memory (e.g.
BatchOperation._enable_shared_memory()).Root cause
__del__referenced module-level names directly:During interpreter shutdown CPython clears module dicts, setting these globals to
None. ASharedMemoryArrayinstance that outlives the module then hitsNone.mmapand raises.Fix
Bind the
mmap.mmapandshared_memory.SharedMemorytypes and the_del_shmhelper as default arguments (bound at import time, so they survive module teardown), and reach the class attributes viatype(self)instead of theSharedMemoryArrayglobal.Test
Added
test_del_after_module_globals_cleared, which clearsmmap,shared_memory,SharedMemoryArrayand_del_shmon the module and verifies deletion still unlinks the shared memory block without raising.📚 Documentation preview 📚: https://google-grain--1386.org.readthedocs.build/