Bug summary

When usingmatplotlib.colorbar.make_axes function,plt.close() does not clear the new colorbar axes from memory. Tested for the Qt5 backend only. Maybe related to#22002, at least in the sense that I see no leak for Qt5 when no colorbar axes are added.

Code for reproduction

%pylabqt5frommatplotlibimportcolorbarimportpsutilimportgcp=psutil.Process()foriinrange(5):fig,ax=plt.subplots(1,1)ax.imshow(random.normal(size=(100,100)))cax=colorbar.make_axes(ax)plt.savefig("test.png")plt.pause(0.1)plt.close(fig)delfigdelaxdelcaxgc.collect()print(p.memory_full_info().uss/1e6)

Actual outcome

250.744832
255.209472
259.514368
264.13056
268.099584

Expected outcome

Constant memory usage, as is when the line
cax = colorbar.make_axes(ax)
is commented out.

Additional information

No response

Operating system

Windows

Matplotlib Version

3.4.2

Matplotlib Backend

Qt5Agg (PyQt)

Python version

3.7.6

Jupyter version

No response

Installation

from source (.tar.gz)