Description

chacabuco

opened on Sep 28, 2023

Issue body actions

Bug summary

with mypy, MinuteLocator results in error:

error: Call to untyped function "MinuteLocator" in typed context [no-untyped-call]

Code for reproduction

import matplotlib.dates as mdates

mdates.MinuteLocator(byminute=range(0, 60, 5))
# run mypy --strict

Actual outcome

error: Call to untyped function "MinuteLocator" in typed context [no-untyped-call]

Expected outcome

No Mypy error

Additional information

No response

Operating system

Ubuntu

Matplotlib Version

3.8.0

Matplotlib Backend

QTAgg

Python version

3.8.10

Jupyter version

No response

Installation

pip

Reacted by John Hagen

Activity

1. oscargus

   added

   topic: date handling

   topic: typing

   on Sep 28, 2023
2. ksunden commented on Sep 28, 2023

   

   ksunden

   on Sep 28, 2023

   Member

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   Units handling is a second portion which was omitted from the first round of type hinting.

   While much of it should be relatively straightforward (at the very least formatters/locators/etc, as in this example) the units portions of the code have quite a bit of dynamic behavior that is not always possible to capture in a static typing context.

   We can (and should) do better where we are able, but addressing units as a whole is a relatively large typing task.

   Similar to #26941, the base class for Locators is type hinted, and so some level of benefit from type hints can be gained by using that, but it does not address the constructor call.

   In general I think that --strict is often too strict especially when it comes to the no-untyped-call check

   I would perhaps suggest adding a config for matplotlib to ignore this rule:

   https://mypy.readthedocs.io/en/stable/config_file.html#example-mypy-ini

   https://mypy.readthedocs.io/en/stable/config_file.html#example-pyproject-toml

   [[tool.mypy.overrides]]
   module = "matplotlib"
   disallow_untyped_calls = false

   because while I would welcome improving our type hints, there may well continue to be portions that are not type hinted.
3. rcomer

   marked Missing type hints for matplotlib.dates.DateFormatter #29994 as a duplicate of this issue on Aug 4, 2025
4. rcomer commented on Aug 4, 2025

   

   rcomer

   on Aug 4, 2025

   Member

   More actions

   #30126 made a start (against a duplicate issue) but has possibly stalled.

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