matplotlib: missing "plt.get_cmap" and "colors.rgb2hex"

[jli]

Environment data

• Language Server version: 2021.3.1
• OS and version: darwin x64
• Python version (and distribution if applicable, e.g. Anaconda): 3.9.2 (and matplotlib==3.3.4)
• python.analysis.indexing: undefined
• python.analysis.typeCheckingMode: basic

Expected behaviour

The functionsmatplotlib.pyplot.get_cmap and matplotlib.colors.rgb2hex should be recognized.

Actual behaviour

I get red squiggles.

Code Snippet / Additional information

#%%
from matplotlib import cm, colors
from matplotlib import pyplot as plt

def cmap_hex_squiggs(colormap: str, val: float) -> str:
    # "get_cmap" is not a known member of module
    cmap = plt.get_cmap(colormap)
    # "rgb2hex" is not a known member of module
    hex = colors.rgb2hex(cmap(val))
    return hex

def cmap_hex_no_squiggs(colormap: str, val: float) -> str:
    cmap = cm.get_cmap(colormap)
    hex = colors.to_hex(cmap(val))
    return hex

Upon googling, it seems like colors.rgb2hex was renamed to to_hex between matplotlib 1.5.0 and 2.0.0, and it seems like cm.get_cmap is more canonical (per https://matplotlib.org/stable/tutorials/colors/colormaps.html). But FWIW, these old/alternative names still work.

[jakebailey]

Thanks for the report. Note that the stubs we bundle are not yet high quality enough to do strict type checking and are mainly intended to improve the completion experience (versus actually check valid code).

[jakebailey]

I've added the members to colors; they weren't documented but are listed in the code as there for backwards compatibility.

get_cmap is also not documented as in pyplot and is only exported due to an import side effect, but it does appear to be there in the real code without any uses, so I'll add it too.

[jakebailey]

This issue has been fixed in version 2021.3.2, which we've just released. You can find the changelog here: https://github.com/microsoft/pylance-release/blob/main/CHANGELOG.md#202132-17-march-2021