gh-122208: Don't delivery PyDict_EVENT_ADDED until it can't fail#122207
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DinoV merged 3 commits intopython:mainfrom Jul 24, 2024
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gh-122208: Don't delivery PyDict_EVENT_ADDED until it can't fail#122207DinoV merged 3 commits intopython:mainfrom
DinoV merged 3 commits intopython:mainfrom
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carljm
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Looks good, thanks for the fix! Sorry about the debugging session that I presume must have led to this find :)
| MAINTAIN_TRACKING(mp, key, value); | ||
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| if (ix == DKIX_EMPTY) { | ||
| assert(!_PyDict_HasSplitTable(mp)); |
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Was it intentional to remove this assertion? Doesn't seem related to the dict watcher stuff.
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No, thanks for catching that, I'll remove it.
Luckily there was no debugging involved! Just trying to re-factor some existing code to use dict watchers and I was worried about what would happen when the updates would fail (as the existing code handled it). So this will actually make that somewhat cleaner!
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Thanks @DinoV for the PR 🌮🎉.. I'm working now to backport this PR to: 3.12, 3.13. |
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Summary: Back port of: python/cpython#122207 fixing python/cpython#122208 The current dictionary watchers implementation delivers the added event before it checks to see if we need to re-size the dictionary. This resize can fail so the value isn't added, and then the tracker is out of sync with the true state of the dictionary. This moves the delivery of the event to after any necessary allocations have happened. Reviewed By: jbower-fb Differential Revision: D60182094 fbshipit-source-id: f34940e98ce1caadeee364f9d126d35839661961
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Summary: Back port of: python/cpython#122207 fixing python/cpython#122208 The current dictionary watchers implementation delivers the added event before it checks to see if we need to re-size the dictionary. This resize can fail so the value isn't added, and then the tracker is out of sync with the true state of the dictionary. This moves the delivery of the event to after any necessary allocations have happened. Reviewed By: jbower-fb Differential Revision: D60182094 fbshipit-source-id: f34940e98ce1caadeee364f9d126d35839661961
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python#122207) Don't delivery PyDict_EVENT_ADDED until it can't fail
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python#122207) Don't delivery PyDict_EVENT_ADDED until it can't fail
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Currently
PyDict_EVENT_ADDEDcan be delivered when the insert is going to fail due to an OOM. This means the listener has no capability of knowing the true state of the dictionary if it fails.This modifies the events to be delivered before the change has happened but only after any underlying necessary allocations have occurred.
addedevent before it's guaranteed to be successful leading to possible incosistent state #122208