Bug report

Bug summary

Units (e.g. datetime) and scales (e.g. log) both come with their own default locators (various DateLocators, LogLocator) and formatters (various DateFormatters, LogFormatter), which are being set inAxis._update_axisinfo andAxis.set_scale, respectively.

If a locator or formatter hasalready been manually set on the axis, then setting units willnot override the user-set locator/formatter -- this is tracked using the slighly awkwardly namedisDefault_{maj,min}{loc,fmt}. On the other hand, setting a scalewill override locator/formatters previously set.

Code for reproduction

frompylabimport*subplot(121)xticks([])xscale("log")subplot(122)xticks([])plot_date([1,2], [3,4])show()

Actual outcome

Expected outcome

Consistent behavior between the two cases.#18571 (comment) is one where scales also respecting user-set locators/formatters would be nice, but I can also see an argument for the opposite behavior for simplicity...

Matplotlib version

• Operating system: linux
• Matplotlib version: HEAD
• Matplotlib backend (print(matplotlib.get_backend())): any
• Python version: 38
• Jupyter version (if applicable):
• Other libraries: