René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Crash in `DistributionFinder.context` because it is using `vars(self).update(kwargs)` under memory preasure","articleBody":"# Crash report\n\nOriginal report: https://gist.github.com/devdanzin/bf9fec4554c58c2a279b05b7ff8e6d9b (it produces the correct repro, but everything else is not correct, since it is AI generated and can be fuzzy).\n\nHere's the real picture.\n\nThis class raises an error: \n\nhttps://github.com/python/cpython/blob/1785f4b35f899704df0be54cba3776906186b2b1/Lib/importlib/metadata/__init__.py#L742-L750\n\nRepro:\n\n```python\nimport faulthandler, importlib.metadata\nfaulthandler.enable()\nfrom _testcapi import set_nomemory\nfor start in range(40):\n    set_nomemory(start)\n    try:\n        importlib.metadata.metadata(\"f\")\n    except BaseException:\n        pass\nprint(\"done, no crash\")\n```\n\nError:\n\n```\nFatal Python error: _Py_Dealloc: Deallocator of type 'Context' cleared the current exception\nPython runtime state: initialized\n\nStack (most recent call first):\n  File \"/Users/sobolev/Desktop/cpython/Lib/importlib/metadata/__init__.py\", line 465 in from_name\n  File \"/Users/sobolev/Desktop/cpython/Lib/importlib/metadata/__init__.py\", line 1091 in metadata\n  File \"/Users/sobolev/Desktop/cpython/ex.py\", line 7 in \u003cmodule\u003e\n\nExtension modules: _testcapi (total: 1)\n[1]    14108 abort      ./python.exe ex.py\n```\n\nI tested this hack, no crash:\n\n```python\ndiff --git Lib/importlib/metadata/__init__.py Lib/importlib/metadata/__init__.py\nindex 32f4b7d2d6e..43ec93db749 100644\n--- Lib/importlib/metadata/__init__.py\n+++ Lib/importlib/metadata/__init__.py\n@@ -777,7 +777,8 @@ class Context:\n         \"\"\"\n \n         def __init__(self, **kwargs):\n-            vars(self).update(kwargs)\n+            for k, v in kwargs.items():\n+                setattr(self, k, v)\n \n         @property\n         def path(self) -\u003e list[str]:\n```\n\nBut, this is clearly not a proper fix. Because for some reason the exception is cleared somewhere.\n\nAfter:\n\n```\n» ./python.exe ex.py\nobject address  : 0x20002128190\nobject refcount : 3\nobject type     : 0x101267e70\nobject type name: MemoryError\nobject repr     : \nlost sys.stderr\nobject address  : 0x20002128110\nobject refcount : 3\nobject type     : 0x101267e70\nobject type name: MemoryError\nobject repr     : \nlost sys.stderr\n```\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-152981\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/sobolevn","@type":"Person","name":"sobolevn"},"datePublished":"2026-06-24T13:52:48.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/152083/cpython/issues/152083"}