fix: gtk module search paths for snap (#177976)

resources/linux/snap/electron-launch

@@ -216,6 +216,12 @@ fi
 
 append_dir GTK_PATH "$SNAP/usr/lib/$ARCH/gtk-3.0"
 append_dir GTK_PATH "$SNAP/usr/lib/gtk-3.0"
+# We don't have gtk libraries in this path but
+# enforcing this environment variable will disallow
+# gtk binaries like `gtk-query-immodules` to not search
+# in system default library paths.
+# Based on https://gitlab.gnome.org/GNOME/gtk/-/blob/main/gtk/gtkmodules.c#L104-136
+export GTK_EXE_PREFIX="$SNAP/usr"
 
 # ibus and fcitx integration
 GTK_IM_MODULE_DIR="$SNAP_USER_COMMON/.cache/immodules"

resources/linux/snap/snapcraft.yaml

@@ -35,6 +35,7 @@ parts:
       - libgl1
       - libglib2.0-0
       - libgtk-3-0
+      - libibus-1.0-5
       - libnss3
       - libpango-1.0-0
       - libsecret-1-0

src/vs/platform/native/electron-main/nativeHostMainService.ts

@@ -454,11 +454,13 @@ export class NativeHostMainService extends Disposable implements INativeHostMain
 		const gtkIMModuleFile = process.env['GTK_IM_MODULE_FILE'];
 		const gdkBackend = process.env['GDK_BACKEND'];
 		const gioModuleDir = process.env['GIO_MODULE_DIR'];
+		const gtkExePrefix = process.env['GTK_EXE_PREFIX'];
 		delete process.env['GDK_PIXBUF_MODULE_FILE'];
 		delete process.env['GDK_PIXBUF_MODULEDIR'];
 		delete process.env['GTK_IM_MODULE_FILE'];
 		delete process.env['GDK_BACKEND'];
 		delete process.env['GIO_MODULE_DIR'];
+		delete process.env['GTK_EXE_PREFIX'];
 
 		shell.openExternal(url);
 
@@ -468,6 +470,7 @@ export class NativeHostMainService extends Disposable implements INativeHostMain
 		process.env['GTK_IM_MODULE_FILE'] = gtkIMModuleFile;
 		process.env['GDK_BACKEND'] = gdkBackend;
 		process.env['GIO_MODULE_DIR'] = gioModuleDir;
+		process.env['GTK_EXE_PREFIX'] = gtkExePrefix;
 	}
 
 	moveItemToTrash(windowId: number | undefined, fullPath: string): Promise<void> {