Regression: XShape rendering artifacts

Affected version

• Arch Linux with Mutter 3.34.3+14+g59e9b073-1
• Happens on both X11 and Wayland sessions

Bug summary

Rendering artifacts for all applications that use the XShape extension. This happens only when there are no windows underneath the shaped window, just the desktop wallpaper. Can be tested by running the oclock or xeyes xorg demos. Most notably affects the Android emulator from the Android SDK, which uses XShape.

Note: applications that use transparency to achieve shaping (instead of the XShape extension) have no issues.

Steps to reproduce

1. sudo pacman -S xorg-oclock
2. oclock
3. drag the oclock window around, having no other windows underneath

What happens

Rendering artifacts in the excluded region

Additional informations

Graphics card: Intel HD3000