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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Confusing error message when home config directory not writable","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\nIf matplotlib is run in an environment without a writable home directory, a very confusing error message is printed in which the configdir and the tempdir are interchanged. \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\n1. In Linux, create a user `someone` with no home directory. \r\n2. Run Python with a command like\r\n\r\n    sudo -u someone python3\r\n\r\n3. In the Python shell, type `import matplotlib`\r\n\r\n**Actual outcome**\r\n\r\n\u003c!--The output produced by the above code, which may be a screenshot, console output, etc.--\u003e\r\n\r\n```\r\nMatplotlib created a temporary config/cache directory at /root/.config/matplotlib because the default path (/tmp/matplotlib-9yoi7m8l) is not a writable directory; it is highly recommended to set the MPLCONFIGDIR environment variable to a writable directory, in particular to speed up the import of Matplotlib and to better support multiprocessing.\r\n```\r\n\r\n**Expected outcome**\r\n\r\n\u003c!--A description of the expected outcome from the code snippet--\u003e\r\n\u003c!--If this used to work in an earlier version of Matplotlib, please note the version it used to work on--\u003e\r\n```\r\nMatplotlib created a temporary config/cache directory at /tmp/matplotlib-9yoi7m8l because the default path (/root/.config/matplotlib) is not a writable directory; it is highly recommended to set the MPLCONFIGDIR environment variable to a writable directory, in particular to speed up the import of Matplotlib and to better support multiprocessing.\r\n```\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: Ubuntu 18.04\r\n  * Matplotlib version: 3.3.0\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): agg\r\n  * Python version: 3.9.0b4\r\n  * Jupyter version (if applicable): N/A\r\n  * Other libraries: N/A\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\n\r\nMatplotlib was compiled from source. The error is at line 482 in `__init__.py` at the root level in the source tree. The parameters are the wrong way round.","author":{"url":"https://github.com/trampgeek","@type":"Person","name":"trampgeek"},"datePublished":"2020-07-22T03:41:11.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/18011/matplotlib/issues/18011"}