fix: pre-emptively disable hw accel where required

Author: jnsgruk

snap/local/opt/Mattermost/fix-default-download-dir

@@ -36,7 +36,8 @@ fi
 if [[ -f "$CONFIG_PATH" ]]; then
     # Check for a likely broken path and replace if needed
     if grep "downloadLocation" "$CONFIG_PATH" | grep -q "snap/mattermost-desktop"; then
-        sed -i -E "s|downloadLocation.*$|downloadLocation\": \"$DOWNLOAD_DIR\",|g" "$CONFIG_PATH"
+        jq --arg p "$DOWNLOAD_DIR" '.downloadLocation = $p' "$CONFIG_PATH" > "$CONFIG_PATH.tmp"
+        mv "$CONFIG_PATH.tmp" "$CONFIG_PATH"
     fi
 else
     # No config file exists, so write a sensible default downloadLocation into a new config

snap/local/opt/Mattermost/fix-hardware-accel-with-no-renderer

@@ -0,0 +1,29 @@
+#!/bin/bash
+
+# Since v6.0.0, Mattermost Desktop fails to launch on machines
+# that do not support hardware acceleration.
+#
+# The issue was reported upstream:
+# https://github.com/mattermost/desktop/issues/3559
+#
+# The Mattermost configuration file can be adjusted to disable
+# hardware acceleration, which enables the app to start.
+#
+# This script attempts to detect cases where there is unlikely
+# to be adequate hardware acceleration, and either updates an
+# existing configuration file or creates a new one with the
+# appropriate setting.
+
+CONFIG_PATH="${SNAP_USER_DATA}/.config/Mattermost/config.json"
+
+# If the rendering device string is 'llvmpipe' then it's likely that the
+# app will crash with hardware acceleration enabled.
+if glxinfo | grep -q llvmpipe; then
+    # Disable hardware acceleration in the configuration file.
+    if [[ -f "$CONFIG_PATH" ]]; then
+        jq '.enableHardwareAcceleration = false' "$CONFIG_PATH" > "$CONFIG_PATH.tmp"
+        mv "$CONFIG_PATH.tmp" "$CONFIG_PATH"
+    fi
+fi
+
+exec "$@"

snap/snapcraft.yaml

@@ -42,6 +42,10 @@ parts:
     override-build: |
       craftctl default
       sed -i 's|Icon=mattermost-desktop|Icon=/usr/share/icons/hicolor/256x256/apps/mattermost-desktop.png|' ${CRAFT_PART_INSTALL}/usr/share/applications/mattermost-desktop.desktop
+    stage-packages:
+      # Needed for the fix-hardware-accel-with-no-renderer script
+      - mesa-utils
+      - jq
     prime:
       - -opt/Mattermost/chrome-sandbox
 
@@ -53,7 +57,9 @@ parts:
 apps:
   mattermost-desktop:
     extensions: [gnome]
-    command-chain: [opt/Mattermost/fix-default-download-dir]
+    command-chain:
+      - opt/Mattermost/fix-default-download-dir
+      - opt/Mattermost/fix-hardware-accel-with-no-renderer
     command: launcher.sh
     desktop: usr/share/applications/mattermost-desktop.desktop
     autostart: mattermost-desktop.desktop