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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"PEP 688: Crash if `__release_buffer__` is called while an exception is active","articleBody":"```\r\nclass A:\r\n    def __buffer__(self, flags):\r\n            return memoryview(bytes(8))\r\n    def __release_buffer__(self, view):\r\n            pass # do not need to do anything here, just needs to exist\r\n\r\nb = bytearray(8)\r\nm = memoryview(b) # now b.extend will raise an exception due to exports\r\nb.extend(A())\r\n```\r\nIn a debug build this crashes with `Assertion failed: (!PyErr_Occurred()), function _PyType_Lookup, file typeobject.c, line 4707.`\r\n\r\nReported by @chilaxan. I'll work on a fix later today.\r\n\r\nMost likely, the fix will be to call `PyErr_Fetch`/`PyErr_Restore` around calls to Python `__release_buffer__` methods.\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-104378\n* gh-104417\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/JelleZijlstra","@type":"Person","name":"JelleZijlstra"},"datePublished":"2023-05-10T21:56:23.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/104371/cpython/issues/104371"}