Bug summary

First invocation of plt.plot() resets mpl.rcParams['figure.dpi'].

Code for reproduction

# Only tested in Jupyter

import matplotlib as mpl
import matplotlib.pyplot as plt

mpl.rcParams['figure.dpi'] = 300

print(mpl.rcParams['figure.dpi'])
plt.plot()
print(mpl.rcParams['figure.dpi'])

Actual outcome

300.0
72.0

Expected outcome

300.0
300.0

Additional information

This happens only at the very first invocation of plt.plot(), while on subsequent plt.plot() calls mpl.rcParams['figure.dpi'] will no longer be overwritten.

Other rcParams values seem not to be affected (but I've not tested them all).

I have never observed this behavior in any of the previous matplotlib versions, so the bug must have been introduced in the latest version (3.5.2).

Operating system

Windows 10

Matplotlib Version

3.5.2

Matplotlib Backend

module://matplotlib_inline.backend_inline

Python version

Python 3.9.12

Jupyter version

3.4.0

Installation

conda