Bug summary

setting figure size using the figsize parameter to matplotlib.pyplot.figure works just fine, but setting it to a different value in the same script fails in case the first argument to the figure call is an identifier.

Code for reproduction

import matplotlib.pyplot
# first call
fig = matplotlib.pyplot.figure(1,figsize=(1,2))
fig.get_figheight()
fig.get_figwidth()
# second call
fig = matplotlib.pyplot.figure(1,figsize=(3,4))
fig.get_figheight()
fig.get_figwidth()

Actual outcome

>>> import matplotlib.pyplot
>>> # first call
>>> fig = matplotlib.pyplot.figure(1,figsize=(1,2))
Qt: Session management error: Could not open network socket
>>> fig.get_figheight()
2.0
>>> fig.get_figwidth()
1.0
>>> # second call
>>> fig = matplotlib.pyplot.figure(1,figsize=(3,4))
>>> fig.get_figheight()
2.0
>>> fig.get_figwidth()
1.0
>>> 

Expected outcome

The second call should change the figure size and the get_figheight/get_figwidth methods should report the changed size.

Additional information

Note that the problem does not occur if no identifier is provided to the figure call, so this works just fine:

fig = matplotlib.pyplot.figure(figsize=(3,4))
fig.get_figheight()
fig.get_figwidth()

Operating system

Fedora 39 linux

Matplotlib Version

3.8.2

Matplotlib Backend

QtAgg

Python version

Python 3.12.2

Jupyter version

n.a.

Installation

Linux package manager