Cherry-pick patch to fix mirror mode crash when monitor resolutions don't match

LP: #2026228

debian/patches/Check-best_mode-exist-before-adding-flag.patch

+From: Dirk Su <dirk.su@canonical.com>
+Date: Mon, 26 Jun 2023 16:38:48 +0800
+Subject: Check best_mode exist before adding flag
+
+When there is no compatible clone mode, the best_mode will be NULL
+. It will cause gnome-control-center crash when access to the
+variable.
+
+(cherry picked from commit b7c0c42317db9bea85cbf83667babf2d73a10b4a)
+---
+ panels/display/cc-display-config-dbus.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/panels/display/cc-display-config-dbus.c b/panels/display/cc-display-config-dbus.c
+index e054d00..e6733ec 100644
+--- a/panels/display/cc-display-config-dbus.c
++++ b/panels/display/cc-display-config-dbus.c
+@@ -1440,7 +1440,8 @@ cc_display_config_dbus_generate_cloning_modes (CcDisplayConfig *pself)
+         best_mode = virtual_mode;
+     }
+ 
+-  best_mode->flags |= MODE_PREFERRED;
++  if (best_mode)
++    best_mode->flags |= MODE_PREFERRED;
+ 
+   return clone_modes;
+ }

debian/patches/series

@@ -30,3 +30,4 @@ ubuntu/sound-Add-a-button-to-select-the-default-theme.patch
 ubuntu/applications-Launch-snap-store-if-it-is-installed.patch
 ubuntu/display-Allow-fractional-scaling-to-be-enabled.patch
 ubuntu/mouse-Add-animations-following-the-accent-colors.patch
+Check-best_mode-exist-before-adding-flag.patch