Bug report

Bug summary

Hi,

I believe I have found a memory issue when plotting multiple figures with the macOS backend.

Here is a minimal working example:

importsysimportmatplotlib.pyplotaspltimportnumpyasnpimportmatplotlib#matplotlib.use('agg')data=np.random.rand(60,60)defplot_expr(plot_name):plt.figure(figsize=(9,8))foriinrange(60):plt.plot(data[i, :])plt.savefig(plot_name)plt.close('all')if__name__=="__main__":print(f'python:{sys.version}')print(f'matplotlib:{matplotlib.__version__}')print(f'backend:{matplotlib.get_backend()}')foriinrange(50):print(f'{i}...')plot_expr(f'leak_{i}')

When running the code withmemory-profiler, I obtain something like:

Even though I am explicitly calling theplt.close() function.

When using the'agg' backend instead of the'MacOSX' backend by uncommenting line 6, I get:

Which I would expect to be the normal behavior.

As I have been unable to reproduce this on Linux, I assume that the issue is with the macOS backend.

Matplotlib version

• Operating system:macOS 11.2.1
• Matplotlib version3.3.4
• Matplotlib backendMacOSX
• Python version:3.7.9

I installed Python viavenv and matplotlib viapip.

Cheers,

Théotime