Add command-line option to not do liboverride autoresync on fileload.

The new --disable-liboverride-auto-resync commandline option will prevent
running liboverride auto-resync immediately after loading a blendfile.

This is an alternative way to setting the User Preferences Debug option
`No Override Auto Resync`.

-------

Some quick performances tests:
Loading a Gold production file goes from 26.5s to 25.9s.

Combined with the recent `--disable-depsgraph-on-file-load` option, it
goes from 3.5s to 2.9s, so another nice extra 15% speedup when only
bare-metal blendfile loading is needed.

Pull Request: https://projects.blender.org/blender/blender/pulls/132017

source/blender/blenkernel/BKE_global.hh

@@ -292,6 +292,14 @@ enum {
    */
   G_BACKGROUND_NO_DEPSGRAPH = 1 << 2,
 
+  /**
+   * Do not perform automatic resync of library overrides on blendfile load.
+   *
+   * NOTE: runtime version of #UserDef_Experimental.no_override_auto_resync, both values are OR'ed
+   * together.
+   */
+  G_LIBOVERRIDE_NO_AUTO_RESYNC = 1 << 3,
+
   // G_FILE_DEPRECATED_9 = (1 << 9),
   G_FILE_NO_UI = (1 << 10),
 
@@ -330,7 +338,8 @@ enum {
  * This means we can change the values without worrying about do-versions.
  */
 #define G_FILE_FLAG_ALL_RUNTIME \
-  (G_BACKGROUND_NO_DEPSGRAPH | G_FILE_NO_UI | G_FILE_RECOVER_READ | G_FILE_RECOVER_WRITE)
+  (G_BACKGROUND_NO_DEPSGRAPH | G_LIBOVERRIDE_NO_AUTO_RESYNC | G_FILE_NO_UI | \
+   G_FILE_RECOVER_READ | G_FILE_RECOVER_WRITE)
 
 /** #Global.moving, signals drawing in (3d) window to denote transform */
 enum {

source/blender/blenkernel/BKE_lib_override.hh

@@ -40,6 +40,12 @@ struct ReportList;
 struct Scene;
 struct ViewLayer;
 
+namespace blender::bke::liboverride {
+
+bool is_auto_resync_enabled();
+
+}  // namespace blender::bke::liboverride
+
 /**
  * Initialize empty overriding of \a reference_id by \a local_id.
  */

source/blender/blenkernel/intern/blendfile.cc

@@ -1202,7 +1202,7 @@ static void setup_app_data(bContext *C,
 
   BLI_assert(BKE_main_namemap_validate(bmain));
 
-  if (mode != LOAD_UNDO && !USER_EXPERIMENTAL_TEST(&U, no_override_auto_resync)) {
+  if (mode != LOAD_UNDO && liboverride::is_auto_resync_enabled()) {
     reports->duration.lib_overrides_resync = BLI_time_now_seconds();
 
     BKE_lib_override_library_main_resync(

source/blender/blenkernel/intern/blendfile_link_append.cc

@@ -64,6 +64,8 @@
 
 static CLG_LogRef LOG = {"bke.blendfile_link_append"};
 
+using namespace blender::bke;
+
 /* -------------------------------------------------------------------- */
 /** \name Link/append context implementation and public management API.
  * \{ */
@@ -1997,9 +1999,7 @@ void BKE_blendfile_library_relocate(BlendfileLinkAppendContext *lapp_context,
   BKE_library_main_rebuild_hierarchy(bmain);
 
   /* Resync overrides if needed. */
-  if (!USER_EXPERIMENTAL_TEST(&U, no_override_auto_resync) &&
-      lapp_context->params->context.scene != nullptr)
-  {
+  if (liboverride::is_auto_resync_enabled() && lapp_context->params->context.scene != nullptr) {
     BlendFileReadReport report{};
     report.reports = reports;
     BKE_lib_override_library_main_resync(bmain,

source/blender/blenkernel/intern/lib_override.cc

@@ -77,6 +77,16 @@ using namespace blender::bke;
 static CLG_LogRef LOG = {"bke.liboverride"};
 static CLG_LogRef LOG_RESYNC = {"bke.liboverride_resync"};
 
+namespace blender::bke::liboverride {
+
+bool is_auto_resync_enabled()
+{
+  return !USER_EXPERIMENTAL_TEST(&U, no_override_auto_resync) &&
+         (G.fileflags & G_LIBOVERRIDE_NO_AUTO_RESYNC) == 0;
+}
+
+}  // namespace blender::bke::liboverride
+
 static void lib_override_library_property_copy(IDOverrideLibraryProperty *op_dst,
                                                IDOverrideLibraryProperty *op_src);
 static void lib_override_library_property_operation_copy(

source/blender/makesrna/intern/rna_userdef.cc

@@ -7510,7 +7510,8 @@ static void rna_def_userdef_experimental(BlenderRNA *brna)
   RNA_def_property_ui_text(prop,
                            "No Override Auto Resync",
                            "Disable library overrides automatic resync detection and process on "
-                           "file load (can be useful to help fixing broken files)");
+                           "file load (can be useful to help fixing broken files). Also see the "
+                           "`--disable-liboverride-auto-resync` command line option");
 
   prop = RNA_def_property(srna, "use_new_point_cloud_type", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, nullptr, "use_new_point_cloud_type", 1);

source/creator/creator_args.cc

@@ -1124,6 +1124,20 @@ static int arg_handle_disable_depsgraph_on_file_load(int /*argc*/,
   return 0;
 }
 
+static const char arg_handle_disable_liboverride_auto_resync_doc[] =
+    "\n"
+    "\tDo not perform library override automatic resync when loading a new blendfile.\n"
+    "\n"
+    "\tNOTE: this is an alternative way to get the same effect as when setting the\n"
+    "\t`No Override Auto Resync` User Preferences Debug option.";
+static int arg_handle_disable_liboverride_auto_resync(int /*argc*/,
+                                                      const char ** /*argv*/,
+                                                      void * /*data*/)
+{
+  G.fileflags |= G_LIBOVERRIDE_NO_AUTO_RESYNC;
+  return 0;
+}
+
 static const char arg_handle_log_level_set_doc[] =
     "<level>\n"
     "\tSet the logging verbosity level (higher for more details) defaults to 1,\n"
@@ -2693,6 +2707,12 @@ void main_args_setup(bContext *C, bArgs *ba, bool all)
                CB(arg_handle_disable_depsgraph_on_file_load),
                nullptr);
 
+  BLI_args_add(ba,
+               nullptr,
+               "--disable-liboverride-auto-resync",
+               CB(arg_handle_disable_liboverride_auto_resync),
+               nullptr);
+
   BLI_args_add(ba, "-a", nullptr, CB(arg_handle_playback_mode), nullptr);
 
   BLI_args_add(ba, "-d", "--debug", CB(arg_handle_debug_mode_set), ba);