René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: Pyparsing warnings emitted in mathtext","articleBody":"### Bug summary\r\n\r\nWhen plotting anything with at least one logarithmic axes (`plt.semilogx()`, `plt.semilogy()`, `plt.loglog()`) I get two warnings emitted due to code in `_mathtext.py`. These warnings are not emitted by default, but appears when running Python with e.g. [`-Wdefault`](https://docs.python.org/3/using/cmdline.html#cmdoption-W).\r\n\r\n### Code for reproduction\r\n\r\n```python\r\nimport matplotlib.pyplot as plt\r\nplt.semilogx([1, 2], [3, 4])\r\nplt.savefig('plot.png')\r\n```\r\n\r\n\r\n### Actual outcome\r\n\r\n```\r\n/path/to/python/lib/python3.9/site-packages/matplotlib/_mathtext.py:1871: UserWarning: warn_name_set_on_empty_Forward: setting results name 'sym' on Forward expression that has no contained expression\r\n  - p.placeable(\"sym\"))\r\n/path/to/python/lib/python3.9/site-packages/matplotlib/_mathtext.py:1876: UserWarning: warn_ungrouped_named_tokens_in_collection: setting results name 'name' on ZeroOrMore expression collides with 'name' on contained expression\r\n  \"{\" + ZeroOrMore(p.simple | p.unknown_symbol)(\"name\") + \"}\")\r\n```\r\n\r\n### Expected outcome\r\n\r\nNo warnings/text should be printed.\r\n\r\n### Additional information\r\n\r\nTo see the warnings from the above code, save it to e.g. `test.py` and run it as either\r\n```bash\r\npython -Wdefault test.py\r\n```\r\nor\r\n```\r\nPYTHONWARNINGS=default python test.py\r\n```\r\n\r\nThe two warnings are triggered by the following lines within `matplotlib/_mathtext.py`:\r\n```python3\r\n        p.accent \u003c\u003c= (\r\n            csnames(\"accent\", [*self._accent_map, *self._wide_accents])\r\n            - p.placeable(\"sym\")\r\n```\r\n\r\n```python3\r\n        p.operatorname \u003c\u003c= cmd(\r\n            r\"\\operatorname\",\r\n            \"{\" + ZeroOrMore(p.simple | p.unknown_symbol)(\"name\") + \"}\")\r\n```\r\nwhere the various attributes on `p` are instances of `pyparsing.Forward`.\r\n\r\nThe warnings appear with Pyparsing versions 3.0.0–3.0.9 but not prior to 3.0.0 (e.g. 2.4.7). Also, the warnings only appear for Matplotlib versions 3.6.0–3.6.3, not e.g. 3.5.3\r\n\r\n\r\n### Operating system\r\n\r\nLinux Mint 20\r\n\r\n### Matplotlib Version\r\n\r\n3.6.3\r\n\r\n### Matplotlib Backend\r\n\r\nQtAgg\r\n\r\n### Python version\r\n\r\n3.8.5\r\n\r\n\r\n### Installation\r\n\r\npip","author":{"url":"https://github.com/jmd-dk","@type":"Person","name":"jmd-dk"},"datePublished":"2023-02-12T16:19:43.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/25204/matplotlib/issues/25204"}