Xvfb error while trying to open multiple xvfb screens in single python session

General information:

• OS name: Ubuntu
• OS version: 20.04
• OS architecture: 64 bits
• Resolutions:
  • Monitor 1: 1920x1080
• Python version: 3.8.10
• MSS version: 6.1.0

For GNU/Linux users:

• Display server protocol and version, if known: Xorg
• Desktop Environment: Gnome
• Composite Window Manager name and version: Not sure

Description of the warning/error

The error comes when I try to call mss.mss() in a single python session with two different Xvfb screens.

Full message

XIO: fatal IO error 0 (Success) on X server ":3" after 8 requests (8 known processed) with 0 events remaining.

Other details

Steps to reproduce:

from xvfbwrapper import Xvfb
import mss
import os

xvfb = Xvfb(width=1920, height=1080, colordepth=24)
xvfb.start()

with mss.mss() as sct:
    pass
xvfb.stop()

xvfb = Xvfb(width=1920, height=1080, colordepth=24)
xvfb.start()

with mss.mss() as sct:
    pass

The error pops up exactly on this line

[BoboTiG]

Actually those internal details were added for performance and memory leak reasons. Your situation is not so frequent, so I would go with the new function to clear the internal state.

[BoboTiG]

Could you try to reset that attribute before the second use of MSS?

from mss.linux import MSS

# (...)
xvfb.stop()

MSS._display_dict.clear()

xvfb = Xvfb(width=1920, height=1080, colordepth=24)
# (...)