Crash on screenshot (Super + S) when avif_screenshots was disabled at build time

[sly547]

Is there an existing issue for this?

• [x] I have searched the existing issues

Are you using any gamescope patches or a forked version of gamescope?

• [x] The issue occurs on upstream gamescope without any modifications

Current Behavior

With the avif_screenshots build option disabled, pressing Super + S inside gamescope causes a crash:

[..]
gamescope: ../gamescope-3.16.2/src/steamcompmgr.cpp:2723: paint_all(bool)::<lambda()>: Assertion `HAVE_AVIF' failed.
[gamescopereaper] [Info]  reaper: Parent of gamescopereaper was killed. Killing children.
(EE) failed to read Wayland events: Broken pipe
Aborted                    WINEPREFIX=~/.wine-64-dxvk/ gamescope -f -w 1920 -h 1200 wine Fallout3ng.exe

Recompiled with the feature enabled, taking a screenshot works 🎉

[gamescope] [Info]  xwm: Screenshot saved to /tmp/gamescope_2025-11-06_13-00-40.avif

Steps To Reproduce

1. Launch a game. Here: gamescope -f -w 1920 -h 1200 wine Fallout3ng.exe
2. Load savegame (or maybe just stay in the main menu)
3. Press Super + S

Hardware information

- Distro: Gentoo Linux x86_64
- CPU: AMD Ryzen 3600
- GPU: Advanced Micro Devices, Inc. [AMD/ATI] Navi 22 [Radeon RX 6700/6700 XT/6750 XT / 6800M/6850M XT]
- Driver Version: Mesa 25.1.9

Software information

- Desktop environment: labwc
- Session type: wayland
- Gamescope version: 3.16.17
- Gamescope launch command(s): gamescope -f -w 1920 -h 1200

Which gamescope backends have the issue you are reporting?

• [x] Wayland (default for nested gamescope)
• [ ] DRM (default for embedded gamescope, i.e. gamescope-session)
• [ ] SDL
• [ ] OpenVR

Logging, screenshots, or anything else

This is on Gentoo Linux which has some minor patches but I'm rather sure they are not related.