René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Memory leak in plt.close() when unshown figures in GUI backends are closed","articleBody":"\u003c!--To help us understand and resolve your issue, please fill out the form to the best of your ability.--\u003e\r\n\u003c!--You can feel free to delete the sections that do not apply.--\u003e\r\n\r\n### Bug report\r\n\r\n**Bug summary**\r\n\r\nWhen creating multiple plots (e.g. in a loop), the allocated memory for the process increases in each iteration even though the figure is cleared each time.\r\n\r\n**Code for reproduction**\r\n\r\n\u003c!--A minimum code snippet required to reproduce the bug.\r\nPlease make sure to minimize the number of dependencies required, and provide\r\nany necessary plotted data.\r\nAvoid using threads, as Matplotlib is (explicitly) not thread-safe.--\u003e\r\n\r\n```python\r\nimport gc\r\nimport matplotlib.pyplot as plt\r\n\r\nfig = plt.figure()\r\nax = fig.add_subplot(111)\r\nfor i in range(5000):\r\n    fig.clf()\r\n    plt.cla()\r\n    ax.plot([0,1,2,3,4,5], [0,1,2,3,4,5])\r\n    plt.close('all')\r\n    plt.close(fig)\r\n\r\n    gc.collect()\r\n```\r\n\r\n**Expected outcome**\r\n\r\nThe allocated memory should not increase in each iteration.\r\n\r\n**Matplotlib version**\r\n\u003c!--Please specify your platform and versions of the relevant libraries you are using:--\u003e\r\n  * Operating system: Arch Linux\r\n  * Matplotlib version (`import matplotlib; print(matplotlib.__version__)`): 3.4.2\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): TkAgg\r\n  * Python version: 3.9.5\r\n  * Jupyter version (if applicable): \r\n  * Other libraries: \r\n\r\n\u003c!--Please tell us how you installed matplotlib and python e.g., from source, pip, conda--\u003e\r\n\u003c!--If you installed from conda, please specify which channel you used if not the default--\u003e\r\nMatplotlib was installed via pip.\r\n","author":{"url":"https://github.com/P-Takenaka","@type":"Person","name":"P-Takenaka"},"datePublished":"2021-05-25T11:23:06.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":6},"url":"https://github.com/20300/matplotlib/issues/20300"}