René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: Matplotlib causes segmentation fault when hovering mouse over graph","articleBody":"### Bug summary\n\nWhen hovering over a graph created with a GTK4 backend, it causes a segmentation fault.\n\n### Code for reproduction\n\n```Python\nimport matplotlib.pyplot as plt\r\nplt.plot(1, 2)\r\nplt.show()\n```\n\n\n### Actual outcome\n\nA graph window shows up. However, when you hover your mouse over the window, some cryptic errors are thrown, and then it causes a segmentation fault:\r\n\r\n```\r\n/home/enprogrammerare/.local/lib/python3.10/site-packages/matplotlib/backends/backend_gtk4.py:160: Warning: g_object_get_qdata: assertion 'G_IS_OBJECT (object)' failed\r\n  guiEvent=controller.get_current_event(),\r\n/home/enprogrammerare/.local/lib/python3.10/site-packages/matplotlib/backends/backend_gtk4.py:160: Warning: g_object_is_floating: assertion 'G_IS_OBJECT (object)' failed\r\n  guiEvent=controller.get_current_event(),\r\n/home/enprogrammerare/.local/lib/python3.10/site-packages/matplotlib/backends/backend_gtk4.py:160: Warning: g_object_ref_sink: assertion 'G_IS_OBJECT (object)' failed\r\n  guiEvent=controller.get_current_event(),\r\n\r\n** (python3:238467): CRITICAL **: 20:20:20.387: pygobject_register_wrapper: assertion 'PyObject_TypeCheck(self, \u0026PyGObject_Type)' failed\r\nSegmentation fault (core dumped)\r\n```\r\n\r\n\r\n\r\n\n\n### Expected outcome\n\nAn empty interactive graph window shows up, which you can hover your mouse over without causing a segmentation fault.\n\n### Additional information\n\nThis bug started to happen when I recently updated Matplotlib to the latest version. In earlier versions, things worked as expected. However, I updated several libraries at the same time, so it might be one of them that is the problem.\r\n\r\nIt only happens when using a GTK4 backend (both Cairo and Agg cause problems). GTK3 works though.\r\n\r\nUsing faulthandler:\r\n```\r\nimport matplotlib.pyplot as plt\r\nimport faulthandler\r\n\r\nfaulthandler.enable()\r\nplt.plot(1,2)\r\nplt.show()\r\n```\r\nYou get the following output:\r\n```\r\n/home/enprogrammerare/.local/lib/python3.10/site-packages/matplotlib/backends/backend_gtk4.py:160: Warning: g_object_get_qdata: assertion 'G_IS_OBJECT (object)' failed\r\n  guiEvent=controller.get_current_event(),\r\n/home/enprogrammerare/.local/lib/python3.10/site-packages/matplotlib/backends/backend_gtk4.py:160: Warning: g_object_is_floating: assertion 'G_IS_OBJECT (object)' failed\r\n  guiEvent=controller.get_current_event(),\r\n/home/enprogrammerare/.local/lib/python3.10/site-packages/matplotlib/backends/backend_gtk4.py:160: Warning: g_object_ref_sink: assertion 'G_IS_OBJECT (object)' failed\r\n  guiEvent=controller.get_current_event(),\r\n\r\n** (python3:239212): CRITICAL **: 20:31:10.373: pygobject_register_wrapper: assertion 'PyObject_TypeCheck(self, \u0026PyGObject_Type)' failed\r\nFatal Python error: Segmentation fault\r\n\r\nCurrent thread 0x00007029b9993000 (most recent call first):\r\n  File \"/usr/lib/python3/dist-packages/gi/overrides/Gio.py\", line 42 in run\r\n  File \"/home/enprogrammerare/.local/lib/python3.10/site-packages/matplotlib/backends/_backend_gtk.py\", line 206 in start_main_loop\r\n  File \"/home/enprogrammerare/.local/lib/python3.10/site-packages/matplotlib/backend_bases.py\", line 3547 in show\r\n  File \"/home/enprogrammerare/.local/lib/python3.10/site-packages/matplotlib/pyplot.py\", line 614 in show\r\n  File \"\u003cstdin\u003e\", line 1 in \u003cmodule\u003e\r\n\r\nExtension modules: numpy._core._multiarray_umath, numpy.linalg._umath_linalg, PIL._imaging, kiwisolver._cext, gi._gi, cairo._cairo, gi._gi_cairo (total: 7)\r\nSegmentation fault (core dumped)\r\n```\n\n### Operating system\n\nUbuntu 22.04.2\n\n### Matplotlib Version\n\n3.10.0\n\n### Matplotlib Backend\n\nGTK4\n\n### Python version\n\n3.10.12\n\n### Jupyter version\n\n_No response_\n\n### Installation\n\npip","author":{"url":"https://github.com/en-programmerare","@type":"Person","name":"en-programmerare"},"datePublished":"2024-12-19T19:34:32.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":8},"url":"https://github.com/29350/matplotlib/issues/29350"}