René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"`PathSimplifier` fails to ignore `CLOSEPOLY` vertices","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\nThis bug does not seem to have surfaced anywhere yet, but `Path`'s with `NaN` vertices at `CLOSEPOLY` can come through `PathNanRemover` in a \"correct\" state but then `PathSimplifier` can sometimes break it:\r\n\r\n**Code for reproduction**/**Actual Outcome**\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\r\n```python\r\n\u003e\u003e\u003e p = Path([(0, 0), (1, 0), (1, 1), (np.nan, np.nan)],\r\n         [Path.MOVETO, Path.LINETO, Path.LINETO, Path.CLOSEPOLY])\r\n\u003e\u003e\u003e # correctly ignores CLOSEPOLY even though it's NaN\r\n\u003e\u003e\u003e p.cleaned(remove_nans=True)\r\nPath(array([[ 0.,  0.],\r\n       [ 1.,  0.],\r\n       [ 1.,  1.],\r\n       [nan, nan],\r\n       [ 0.,  0.]]), array([ 1,  2,  2, 79,  0], dtype=uint8))\r\n\u003e\u003e\u003e # but now for some reason these NaN's are used to populate LINETO's\r\n\u003e\u003e\u003e p.cleaned(remove_nans=True, simplify=True)\r\nPath(array([[ 0.,  0.],\r\n       [ 1.,  0.],\r\n       [ 1.,  1.],\r\n       [nan, nan],\r\n       [nan, nan],\r\n       [ 0.,  0.]]), array([1, 2, 2, 2, 2, 0], dtype=uint8))\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\nThe values of the vertices in a `CLOSEPOLY` should always be ignored, in favor of the most recent `MOVETO`'s vertex values:\r\n\r\n```python\r\n\u003e\u003e\u003e p.cleaned(remove_nans=True, simplify=True)\r\nPath(array([[ 0.,  0.],\r\n       [ 1.,  0.],\r\n       [ 1.,  1.],\r\n       [0, 0],\r\n       [ 0.,  0.]]), array([1, 2, 2, 2, 0], dtype=uint8))\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:\r\n  * Matplotlib version: \r\n  * Matplotlib backend (`print(matplotlib.get_backend())`):\r\n  * Python version:\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\n\r\n","author":{"url":"https://github.com/brunobeltran","@type":"Person","name":"brunobeltran"},"datePublished":"2020-07-13T20:02:55.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/17914/matplotlib/issues/17914"}