Closed
Description
Bug summary
When 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.
Code for reproduction
import matplotlib.pyplot as plt
plt.semilogx([1, 2], [3, 4])
plt.savefig('plot.png')Actual outcome
/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
- p.placeable("sym"))
/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
"{" + ZeroOrMore(p.simple | p.unknown_symbol)("name") + "}")
Expected outcome
No warnings/text should be printed.
Additional information
To see the warnings from the above code, save it to e.g. test.py and run it as either
python -Wdefault test.pyor
PYTHONWARNINGS=default python test.py
The two warnings are triggered by the following lines within matplotlib/_mathtext.py:
p.accent <<= (
csnames("accent", [*self._accent_map, *self._wide_accents])
- p.placeable("sym") p.operatorname <<= cmd(
r"\operatorname",
"{" + ZeroOrMore(p.simple | p.unknown_symbol)("name") + "}")where the various attributes on p are instances of pyparsing.Forward.
The 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
Operating system
Linux Mint 20
Matplotlib Version
3.6.3
Matplotlib Backend
QtAgg
Python version
3.8.5
Installation
pip