[Bug]: `axes.labelsize` is ignored

[urob]

y### Bug summary

In Matplotlib Version 3.7.0, setting axes.labelsize via a mplstyle file or by updating rcParams does not change the font size of xlabel and ylabel.

Code for reproduction

import matplotlib.pyplot as plt

size = 24
plt.style.use("default")
plt.rcParams.update(
    {
        "axes.labelsize": size,  # has no effect
        "axes.titlesize": size,  # works as expected
        "xtick.labelsize": size,  # works as expected
        "ytick.labelsize": size,  # works as expected
    }
)

fig, ax = plt.subplots(constrained_layout=True)
ax.plot([0, 1], [0, 1])
ax.set(title="Title", xlabel="x-label", ylabel="y-label")
plt.show()

Actual outcome

Expected outcome

I would expect the xlabel and ylabel to have font size 24 (same as the tick-labels and the title).

Additional information

The issue seems to only occur in Matplotlib Version 3.7.0 (installed from conda-forge). When downgrading to Version 3.6.2, everything works expected. Here is a minimal conda-environment to reproduce the issue:

# env.yml -- install via "conda env create -f env.yml"
name: minimal_example
channels:
  - conda-forge
dependencies:
  - python=3.10
  # - matplotlib=3.6.2  # works
  - matplotlib=3.7.0  # does not work

In either case, setting the xlabel size directly via plt.xlabel("x-label", size=24) or via ax.set_xlabel("x-label", size=24) works as expected.

Operating system

Windows 11

Matplotlib Version

3.7.0

Matplotlib Backend

module://backend_interagg

Python version

3.10.9

Jupyter version

No response

Installation

conda

[rcomer]

Thanks for the clear report @urob. I have reproduced this, and agree we seem to have broken this at v3.7.

[rcomer]

Bisects to #21253.

[rcomer]

But actually is already fixed by #25237.