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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Hard crash when deleting from Dictionary","articleBody":"### Environment\r\n\r\n-   Pythonnet version: 3.0.5\r\n-   Python version: both 3.12 and 3.13\r\n-   Operating System: MacOS Sequoia 15.1.1\r\n-   .NET Runtime: both 7.0.410 and 8.0.403\r\n\r\n### Details\r\n\r\n-   Describe what you were trying to get done.\r\n\r\nRemove an element from a .NET Dictionary using the del operator (`__delitem__`).\r\n\r\n-   What commands did you run to trigger this issue?\r\n     If you can provide a [Minimal, Complete, and Verifiable example](http://stackoverflow.com/help/mcve) this will help us understand the issue.\r\n\r\nI reduced the problem to the following example, simply run from the command line:\r\n```python\r\nimport pythonnet\r\npythonnet.load('coreclr')\r\nprint(pythonnet.get_runtime_info(), end='\\n\\n')\r\n\r\nimport clr\r\n\r\nfrom System.Collections.Generic import Dictionary\r\nfrom System import Int32, String\r\n\r\nDT = Dictionary[Int32, String]\r\nd = DT()\r\nd[10] = '10'\r\nd[20] = '20'\r\nprint('__delitem__ is implemented by {}'.format(\r\n    next(iter(cls for cls in DT.mro() if hasattr(cls, '__delitem__')))\r\n))\r\ndel d[20]  # crash\r\n```\r\n\r\n-   If there was a crash, please include the traceback here.\r\n\r\nThe program crashed with the following output:\r\n```\r\nRuntime: CoreCLR\r\n=============\r\n  Version:      \u003cundefined\u003e\r\n  Initialized:  True\r\n  Shut down:    False\r\n  Properties:\r\n    HOST_RUNTIME_CONTRACT = 0x600003a840c8\r\n    PROBING_DIRECTORIES =\r\n    RUNTIME_IDENTIFIER = osx-arm64\r\n    FX_DEPS_FILE = /usr/local/share/dotnet/shared/Microsoft.NETCore.App…\r\n    APP_CONTEXT_DEPS_FILES = /usr/local/share/dotnet/shared/Microsoft.N…\r\n    APP_CONTEXT_BASE_DIRECTORY =\r\n    PLATFORM_RESOURCE_ROOTS = :\r\n    NATIVE_DLL_SEARCH_DIRECTORIES = :/usr/local/share/dotnet/shared/Mic…\r\n    TRUSTED_PLATFORM_ASSEMBLIES = /usr/local/share/dotnet/shared/Micros…\r\n\r\n__delitem__ is implemented by \u003cclass 'System.Collections.Generic.Dictionary[Int32,String]'\u003e\r\nUnhandled exception. System.NullReferenceException: Object reference not set to an instance of an object.\r\n   at Python.Runtime.BorrowedReference.DangerousGetAddress() in /home/benedikt/.cache/uv/sdists-v6/.tmpkW03e6/pythonnet-3.0.5/src/runtime/Native/BorrowedReference.cs:line 18\r\n   at Python.Runtime.NewReference..ctor(BorrowedReference reference, Boolean canBeNull) in /home/benedikt/.cache/uv/sdists-v6/.tmpkW03e6/pythonnet-3.0.5/src/runtime/Native/NewReference.cs:line 20\r\n   at Python.Runtime.Runtime.PyTuple_SetItem(BorrowedReference pointer, IntPtr index, BorrowedReference value) in /home/benedikt/.cache/uv/sdists-v6/.tmpkW03e6/pythonnet-3.0.5/src/runtime/Runtime.cs:line 1482\r\n   at Python.Runtime.ClassBase.mp_ass_subscript_impl(BorrowedReference ob, BorrowedReference idx, BorrowedReference v) in /home/benedikt/.cache/uv/sdists-v6/.tmpkW03e6/pythonnet-3.0.5/src/runtime/Types/ClassBase.cs:line 498\r\n[1]    56976 abort      python3.12 /tmp/ramdisk/delme_test_pythonnet.py\r\n```\r\n\r\nNotice that `__delitem__` is also implemented by the `MutableMappingMixin` class [here](https://github.com/pythonnet/pythonnet/blob/dfd746b339dc24d530f7d64768e1c8acf9d84cb4/src/runtime/Mixins/collections.py#L58), which simply calls the `Remove()` method, but `Dictionary` has its own implementation (that I can't find), which takes precedence.\r\nThe former would have worked correctly (tested), as `Remove()` works as usual.","author":{"url":"https://github.com/DiegoBaldassarMilleuno","@type":"Person","name":"DiegoBaldassarMilleuno"},"datePublished":"2024-12-13T11:01:16.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":5},"url":"https://github.com/2530/pythonnet/issues/2530"}