Preferences: support loading factory settings only for app-templates

When app-templates are enabled, support resetting defaults only for the
app-templates.

Without this, it's not possible to reset app-template preferences
without also resetting the default preferences for all settings the
app-template does not override (used when there is no application
template loaded, and other app-templates).

These additional menu items are shown in menus when an app-template has
been loaded.

Address issue raised by T96427.

Reviewed By: mont29, brecht

Ref D16150

4 files changed, 79 insertions, 23 deletions

diff --git a/release/scripts/startup/bl_ui/space_topbar.py b/release/scripts/startup/bl_ui/space_topbar.py
index b1ddd2c611d..3320e1e24a7 100644
--- a/release/scripts/startup/bl_ui/space_topbar.py
+++ b/release/scripts/startup/bl_ui/space_topbar.py
@@ -411,9 +411,16 @@ class TOPBAR_MT_file_defaults(Menu):
                 app_template, has_ext=False))
 
         layout.operator("wm.save_homefile")
-        props = layout.operator("wm.read_factory_settings")
         if app_template:
+            display_name = bpy.path.display_name(iface_(app_template))
+            props = layout.operator("wm.read_factory_settings", text="Load Factory Blender Settings")
             props.app_template = app_template
+            props = layout.operator("wm.read_factory_settings", text="Load Factory %s Settings" % display_name)
+            props.app_template = app_template
+            props.use_factory_startup_app_template_only = True
+            del display_name
+        else:
+            layout.operator("wm.read_factory_settings")
 
 
 # Include technical operators here which would otherwise have no way for users to access.
diff --git a/release/scripts/startup/bl_ui/space_userpref.py b/release/scripts/startup/bl_ui/space_userpref.py
index 441babefd60..a9736feb057 100644
--- a/release/scripts/startup/bl_ui/space_userpref.py
+++ b/release/scripts/startup/bl_ui/space_userpref.py
@@ -109,7 +109,16 @@ class USERPREF_MT_save_load(Menu):
         sub_revert.operator("wm.read_userpref", text="Revert to Saved Preferences")
 
         layout.operator_context = 'INVOKE_AREA'
-        layout.operator("wm.read_factory_userpref", text="Load Factory Preferences")
+
+        app_template = prefs.app_template
+        if app_template:
+            display_name = bpy.path.display_name(iface_(app_template))
+            layout.operator("wm.read_factory_userpref", text="Load Factory Blender Preferences")
+            props = layout.operator("wm.read_factory_userpref", text="Load Factory %s Preferences" % display_name)
+            props.use_factory_startup_app_template_only = True
+            del display_name
+        else:
+            layout.operator("wm.read_factory_userpref", text="Load Factory Preferences")
 
 
 class USERPREF_PT_save_preferences(Panel):
diff --git a/source/blender/windowmanager/intern/wm_files.c b/source/blender/windowmanager/intern/wm_files.c
index 92844dddf4c..e835a5db57b 100644
--- a/source/blender/windowmanager/intern/wm_files.c
+++ b/source/blender/windowmanager/intern/wm_files.c
@@ -1068,6 +1068,12 @@ void wm_homefile_read_ex(bContext *C,
   const bool use_data = params_homefile->use_data;
   const bool use_userdef = params_homefile->use_userdef;
   bool use_factory_settings = params_homefile->use_factory_settings;
+  /* Currently this only impacts preferences as it doesn't make much sense to keep the default
+   * startup open in the case the app-template doesn't happen to define it's own startup.
+   * Unlike preferences where we might want to only reset the app-template part of the preferences
+   * so as not to reset the preferences for all other Blender instances, see: T96427. */
+  const bool use_factory_settings_app_template_only =
+      params_homefile->use_factory_settings_app_template_only;
   const bool use_empty_data = params_homefile->use_empty_data;
   const char *filepath_startup_override = params_homefile->filepath_startup_override;
   const char *app_template_override = params_homefile->app_template_override;
@@ -1180,7 +1186,11 @@ void wm_homefile_read_ex(bContext *C,
 
   /* load preferences before startup.blend */
   if (use_userdef) {
-    if (!use_factory_settings && BLI_exists(filepath_userdef)) {
+    if (use_factory_settings_app_template_only) {
+      /* Use the current preferences as-is (only load in the app_template preferences). */
+      skip_flags |= BLO_READ_SKIP_USERDEF;
+    }
+    else if (!use_factory_settings && BLI_exists(filepath_userdef)) {
       UserDef *userdef = BKE_blendfile_userdef_read(filepath_userdef, NULL);
       if (userdef != NULL) {
         BKE_blender_userdef_data_set_and_free(userdef);
@@ -2254,19 +2264,23 @@ static int wm_userpref_read_exec(bContext *C, wmOperator *op)
   const bool use_data = false;
   const bool use_userdef = true;
   const bool use_factory_settings = STREQ(op->type->idname, "WM_OT_read_factory_userpref");
+  const bool use_factory_settings_app_template_only =
+      (use_factory_settings && RNA_boolean_get(op->ptr, "use_factory_startup_app_template_only"));
 
   UserDef U_backup = U;
 
-  wm_homefile_read(C,
-                   &(const struct wmHomeFileRead_Params){
-                       .use_data = use_data,
-                       .use_userdef = use_userdef,
-                       .use_factory_settings = use_factory_settings,
-                       .use_empty_data = false,
-                       .filepath_startup_override = NULL,
-                       .app_template_override = WM_init_state_app_template_get(),
-                   },
-                   op->reports);
+  wm_homefile_read(
+      C,
+      &(const struct wmHomeFileRead_Params){
+          .use_data = use_data,
+          .use_userdef = use_userdef,
+          .use_factory_settings = use_factory_settings,
+          .use_factory_settings_app_template_only = use_factory_settings_app_template_only,
+          .use_empty_data = false,
+          .filepath_startup_override = NULL,
+          .app_template_override = WM_init_state_app_template_get(),
+      },
+      op->reports);
 
   wm_userpref_read_exceptions(&U, &U_backup);
   SET_FLAG_FROM_TEST(G.f, use_factory_settings, G_FLAG_USERPREF_NO_SAVE_ON_EXIT);
@@ -2307,6 +2321,16 @@ void WM_OT_read_factory_userpref(wmOperatorType *ot)
 
   ot->invoke = WM_operator_confirm;
   ot->exec = wm_userpref_read_exec;
+
+  PropertyRNA *prop;
+
+  /* So it's possible to reset app-template settings without resetting other defaults. */
+  prop = RNA_def_boolean(ot->srna,
+                         "use_factory_startup_app_template_only",
+                         false,
+                         "Factory Startup App-Template Only",
+                         "");
+  RNA_def_property_flag(prop, PROP_HIDDEN | PROP_SKIP_SAVE);
 }
 
 /** \} */
@@ -2349,6 +2373,10 @@ static int wm_homefile_read_exec(bContext *C, wmOperator *op)
                                                      "WM_OT_read_factory_settings");
   const bool use_factory_settings = use_factory_startup_and_userdef ||
                                     RNA_boolean_get(op->ptr, "use_factory_startup");
+  const bool use_factory_settings_app_template_only =
+      (use_factory_startup_and_userdef &&
+       RNA_boolean_get(op->ptr, "use_factory_startup_app_template_only"));
+
   bool use_userdef = false;
   char filepath_buf[FILE_MAX];
   const char *filepath = NULL;
@@ -2405,16 +2433,18 @@ static int wm_homefile_read_exec(bContext *C, wmOperator *op)
     app_template = WM_init_state_app_template_get();
   }
 
-  wm_homefile_read(C,
-                   &(const struct wmHomeFileRead_Params){
-                       .use_data = true,
-                       .use_userdef = use_userdef,
-                       .use_factory_settings = use_factory_settings,
-                       .use_empty_data = use_empty_data,
-                       .filepath_startup_override = filepath,
-                       .app_template_override = app_template,
-                   },
-                   op->reports);
+  wm_homefile_read(
+      C,
+      &(const struct wmHomeFileRead_Params){
+          .use_data = true,
+          .use_userdef = use_userdef,
+          .use_factory_settings = use_factory_settings,
+          .use_factory_settings_app_template_only = use_factory_settings_app_template_only,
+          .use_empty_data = use_empty_data,
+          .filepath_startup_override = filepath,
+          .app_template_override = app_template,
+      },
+      op->reports);
 
   if (use_splash) {
     WM_init_splash(C);
@@ -2459,6 +2489,14 @@ static void read_homefile_props(wmOperatorType *ot)
 
   prop = RNA_def_boolean(ot->srna, "use_empty", false, "Empty", "");
   RNA_def_property_flag(prop, PROP_HIDDEN | PROP_SKIP_SAVE);
+
+  /* So it's possible to reset app-template settings without resetting other defaults. */
+  prop = RNA_def_boolean(ot->srna,
+                         "use_factory_startup_app_template_only",
+                         false,
+                         "Factory Startup App-Template Only",
+                         "");
+  RNA_def_property_flag(prop, PROP_HIDDEN | PROP_SKIP_SAVE);
 }
 
 void WM_OT_read_homefile(wmOperatorType *ot)
diff --git a/source/blender/windowmanager/wm_files.h b/source/blender/windowmanager/wm_files.h
index 1c09f861c6c..1ab8808b70b 100644
--- a/source/blender/windowmanager/wm_files.h
+++ b/source/blender/windowmanager/wm_files.h
@@ -31,6 +31,8 @@ struct wmHomeFileRead_Params {
    * Used for "Restore Factory Settings".
    */
   unsigned int use_factory_settings : 1;
+  /** Read factory settings from the app-templates only (keep other defaults). */
+  unsigned int use_factory_settings_app_template_only : 1;
   /**
    * Load the startup file without any data-blocks.
    * Useful for automated content generation, so the file starts without data.