René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: Nondeterminism in SVG clipPath element id attributes","articleBody":"### Bug summary\r\n\r\nHello - I'm trying to make the [`astroplan`](https://github.com/astropy/astroplan) documentation build [reproducibly](https://reproducible-builds.org/) in Debian, and have found a snag: despite configuring the [`svg.hashsalt`](https://matplotlib.org/stable/users/explain/customizing.html?highlight=svg.hashsalt#matplotlibrc-sample) to successfully make `path` identifiers in some SVG plots generated by `matplotlib` deterministic, there is a remaining problem that `clipPath` identifiers are nondeterministic.\r\n\r\nThe cause appears to be the use of Python object ID (via [`id(...)` calls here](https://github.com/matplotlib/matplotlib/blob/c23ccdde6f0f8c071b09a88770e24452f2859e99/lib/matplotlib/backends/backend_svg.py#L622)) when [generating `clippath` IDs](https://github.com/matplotlib/matplotlib/blob/c23ccdde6f0f8c071b09a88770e24452f2859e99/lib/matplotlib/backends/backend_svg.py#L631).\r\n\r\n### Code for reproduction\r\n\r\n```Python\r\nimport matplotlib as mpl\r\nimport matplotlib.pyplot as plt\r\nimport sys\r\n\r\nmpl.rcParams[\"svg.hashsalt\"] = \"fixed-salt\"\r\n\r\nfig = plt.gcf()\r\nfig.add_subplot(projection=\"polar\")\r\n\r\nplt.savefig(sys.stdout.buffer, format=\"svg\")\r\n```\r\n\r\n\r\n### Actual outcome\r\n\r\nDifferences appear in the `clipPath` identifiers and their references from elsewhere in the SVG output.\r\n\r\n### Expected outcome\r\n\r\nWhen an `svg.hashsalt` value is configured, the SVG output should be deterministic.\r\n\r\n### Additional information\r\n\r\nThis could arguably be an enhancement request rather than a bug.\r\n\r\nConfiguring a static `PYTHONHASHSEED` value does not help to produce deterministic results.\r\n\r\n### Operating system\r\n\r\nDebian GNU/Linux (trixie)\r\n\r\n### Matplotlib Version\r\n\r\n3.6.3\r\n\r\n### Matplotlib Backend\r\n\r\nTkAgg\r\n\r\n### Python version\r\n\r\nPython 3.11.8\r\n\r\n### Jupyter version\r\n\r\nN/A\r\n\r\n### Installation\r\n\r\nLinux package manager","author":{"url":"https://github.com/jayaddison","@type":"Person","name":"jayaddison"},"datePublished":"2024-02-28T11:45:24.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":6},"url":"https://github.com/27831/matplotlib/issues/27831"}