From 3a2fafba7380eefdc628b7ff593497a39bf2318f Mon Sep 17 00:00:00 2001
From: Campbell Barton <campbell@blender.org>
Date: Tue, 30 Apr 2024 13:49:31 +1000
Subject: [PATCH] Revert "Fix hang on startup under Wayland with the WayFire
 compositor"

This reverts commit 3a5389d5abe00aa229b5c6d35d346cb8f7cbe649.

It seems XDG_CURRENT_DESKTOP isn't reliably set,
causing no titlebar on GNOME, see #121241.

The WAYFIRE workaround will need to be resolved another way.
---
 intern/ghost/intern/GHOST_SystemWayland.cc | 38 ++++++++++++++--------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/intern/ghost/intern/GHOST_SystemWayland.cc b/intern/ghost/intern/GHOST_SystemWayland.cc
index 6c7a7fd8acb..51706bc15ee 100644
--- a/intern/ghost/intern/GHOST_SystemWayland.cc
+++ b/intern/ghost/intern/GHOST_SystemWayland.cc
@@ -191,6 +191,15 @@ static bool use_gnome_confine_hack = false;
  */
 #define USE_KDE_TABLET_HIDDEN_CURSOR_HACK
 
+/**
+ * When GNOME is found, require `libdecor`.
+ * This is a hack because it seems there is no way to check if the compositor supports
+ * server side decorations when initializing WAYLAND.
+ */
+#ifdef WITH_GHOST_WAYLAND_LIBDECOR
+#  define USE_GNOME_NEEDS_LIBDECOR_HACK
+#endif
+
 /** \} */
 
 /* -------------------------------------------------------------------- */
@@ -1353,6 +1362,7 @@ struct GWL_Display {
 
 #ifdef WITH_GHOST_WAYLAND_LIBDECOR
   GWL_LibDecor_System *libdecor = nullptr;
+  bool libdecor_required = false;
 #endif
   GWL_XDG_Decor_System *xdg_decor = nullptr;
 
@@ -6970,6 +6980,16 @@ static void global_handle_add(void *data,
 
     added = display->registry_entry != registry_entry_prev;
   }
+  else {
+    /* Not found. */
+#ifdef USE_GNOME_NEEDS_LIBDECOR_HACK
+    if (STRPREFIX(interface, "gtk_shell")) { /* `gtk_shell1` at time of writing. */
+      /* Only require `libdecor` when built with X11 support,
+       * otherwise there is nothing to fall back on. */
+      display->libdecor_required = true;
+    }
+#endif
+  }
 
   CLOG_INFO(LOG,
             2,
@@ -7127,34 +7147,24 @@ GHOST_SystemWayland::GHOST_SystemWayland(bool background)
   }
 
 #ifdef WITH_GHOST_WAYLAND_LIBDECOR
-  bool libdecor_required = false;
-  {
-    /* This seems to be the most reliable way to check if GNOME is running.
-     * Ideally it would be possible to check if the compositor supports SSD. */
-    const char *xdg_current_desktop = getenv("XDG_CURRENT_DESKTOP");
-    if (xdg_current_desktop && STREQ(xdg_current_desktop, "GNOME")) {
-      libdecor_required = true;
-    }
-  }
-
-  if (libdecor_required) {
+  if (display_->libdecor_required) {
     /* Ignore windowing requirements when running in background mode,
      * as it doesn't make sense to fall back to X11 because of windowing functionality
      * in background mode, also LIBDECOR is crashing in background mode `blender -b -f 1`
      * for e.g. while it could be fixed, requiring the library at all makes no sense. */
     if (background) {
-      libdecor_required = false;
+      display_->libdecor_required = false;
     }
 #  ifdef WITH_GHOST_X11
     else if (!has_libdecor && !ghost_wayland_is_x11_available()) {
       /* Only require LIBDECOR when X11 is available, otherwise there is nothing to fall back to.
        * It's better to open without window decorations than failing entirely. */
-      libdecor_required = false;
+      display_->libdecor_required = false;
     }
 #  endif /* WITH_GHOST_X11 */
   }
 
-  if (libdecor_required) {
+  if (display_->libdecor_required) {
     gwl_xdg_decor_system_destroy(display_, display_->xdg_decor);
     display_->xdg_decor = nullptr;