Tool System: store the fallback tool for re-use

The fallback tool was run-time only data,
now it's stored in the blend file.

release/scripts/startup/bl_ui/space_toolsystem_common.py

@@ -354,6 +354,16 @@ class ToolSelectPanelHelper:
                 i += 1
         return None, -1
 
+    @classmethod
+    def _tool_group_active_set_by_id(cls, context, idname_group, idname):
+        item_group = cls._tool_get_group_by_id(context, idname_group, coerce=True)
+        if item_group:
+            for i, item in enumerate(item_group):
+                if item and item.idname == idname:
+                    cls._tool_group_active[item_group[0].idname] = i
+                    return True
+        return False
+
     @staticmethod
     def _tool_active_from_context(context, space_type, mode=None, create=False):
         if space_type in {'VIEW_3D', 'PROPERTIES'}:
@@ -660,10 +670,10 @@ class ToolSelectPanelHelper:
             *,
             is_horizontal_layout=False,
     ):
-        tool_fallback = tool.tool_fallback
+        idname_fallback = tool.idname_fallback
         space_type = tool.space_type
         cls = ToolSelectPanelHelper._tool_class_from_space_type(space_type)
-        item_fallback, _index = cls._tool_get_by_id(context, tool_fallback)
+        item_fallback, _index = cls._tool_get_by_id(context, idname_fallback)
         if item_fallback is not None:
             draw_settings = item_fallback.draw_settings
             if draw_settings is not None:
@@ -700,11 +710,11 @@ class ToolSelectPanelHelper:
             draw_settings(context, layout, tool)
 
         if context.preferences.experimental.use_tool_fallback:
-            tool_fallback = tool.tool_fallback
+            idname_fallback = tool.idname_fallback
         else:
-            tool_fallback = None
+            idname_fallback = None
 
-        if tool_fallback and tool_fallback != item.idname:
+        if idname_fallback and idname_fallback != item.idname:
             tool_settings = context.tool_settings
 
             # Show popover which looks like an enum but isn't one.
@@ -862,6 +872,7 @@ class WM_MT_toolsystem_submenu(Menu):
 
 def _activate_by_item(context, space_type, item, index, *, as_fallback=False):
     cls = ToolSelectPanelHelper._tool_class_from_space_type(space_type)
+    tool = ToolSelectPanelHelper._tool_active_from_context(context, space_type, create=True)
     tool_fallback_id = cls.tool_fallback_id
 
     if as_fallback:
@@ -889,6 +900,12 @@ def _activate_by_item(context, space_type, item, index, *, as_fallback=False):
         # Done, now get the current tool to replace the item & index.
         tool_active = ToolSelectPanelHelper._tool_active_from_context(context, space_type)
         item, index = cls._tool_get_by_id(context, getattr(tool_active, "idname", None))
+    else:
+        # Ensure the active fallback tool is read from saved state (even if the fallback tool is not in use).
+        stored_idname_fallback = tool.idname_fallback
+        if stored_idname_fallback:
+            cls._tool_group_active_set_by_id(context, tool_fallback_id, stored_idname_fallback)
+        del stored_idname_fallback
 
     # Find fallback keymap.
     item_fallback = None
@@ -897,7 +914,6 @@ def _activate_by_item(context, space_type, item, index, *, as_fallback=False):
         item_fallback, _index = cls._tool_get_active_by_index(context, select_index)
     # End calculating fallback.
 
-    tool = ToolSelectPanelHelper._tool_active_from_context(context, space_type, create=True)
     tool.setup(
         idname=item.idname,
         keymap=item.keymap[0] if item.keymap is not None else "",

source/blender/makesdna/DNA_workspace_types.h

@@ -35,8 +35,7 @@ typedef struct bToolRef_Runtime {
   char gizmo_group[64];
   char data_block[64];
 
-  /** Optionally use these when not interacting directly with the primary tools gizmo. */
-  char idname_fallback[64];
+  /** Keymap for #bToolRef.idname_fallback, if set. */
   char keymap_fallback[64];
 
   /** Use to infer primary operator to use when setting accelerator keys. */
@@ -51,6 +50,9 @@ typedef struct bToolRef {
   struct bToolRef *next, *prev;
   char idname[64];
 
+  /** Optionally use these when not interacting directly with the primary tools gizmo. */
+  char idname_fallback[64];
+
   /** Use to avoid initializing the same tool multiple times. */
   short tag;
 

source/blender/makesrna/intern/rna_workspace.c

@@ -192,18 +192,6 @@ static int rna_WorkSpaceTool_widget_length(PointerRNA *ptr)
   return tref->runtime ? strlen(tref->runtime->gizmo_group) : 0;
 }
 
-static void rna_WorkSpaceTool_tool_fallback_get(PointerRNA *ptr, char *value)
-{
-  bToolRef *tref = ptr->data;
-  strcpy(value, tref->runtime ? tref->runtime->idname_fallback : "");
-}
-
-static int rna_WorkSpaceTool_tool_fallback_length(PointerRNA *ptr)
-{
-  bToolRef *tref = ptr->data;
-  return tref->runtime ? strlen(tref->runtime->idname_fallback) : 0;
-}
-
 #else /* RNA_RUNTIME */
 
 static void rna_def_workspace_owner(BlenderRNA *brna)
@@ -270,6 +258,10 @@ static void rna_def_workspace_tool(BlenderRNA *brna)
   RNA_def_property_ui_text(prop, "Identifier", "");
   RNA_def_struct_name_property(srna, prop);
 
+  prop = RNA_def_property(srna, "idname_fallback", PROP_STRING, PROP_NONE);
+  RNA_def_property_ui_text(prop, "Identifier Fallback", "");
+  RNA_def_struct_name_property(srna, prop);
+
   prop = RNA_def_property(srna, "index", PROP_INT, PROP_NONE);
   RNA_def_property_clear_flag(prop, PROP_EDITABLE);
   RNA_def_property_ui_text(prop, "Index", "");
@@ -300,14 +292,6 @@ static void rna_def_workspace_tool(BlenderRNA *brna)
   RNA_def_property_ui_text(prop, "Widget", "");
   RNA_def_property_string_funcs(
       prop, "rna_WorkSpaceTool_widget_get", "rna_WorkSpaceTool_widget_length", NULL);
-  RNA_define_verify_sdna(1);
-
-  prop = RNA_def_property(srna, "tool_fallback", PROP_STRING, PROP_NONE);
-  RNA_def_property_clear_flag(prop, PROP_EDITABLE);
-  RNA_def_property_ui_text(prop, "Fallback", "");
-  RNA_def_property_string_funcs(
-      prop, "rna_WorkSpaceTool_tool_fallback_get", "rna_WorkSpaceTool_tool_fallback_length", NULL);
-  RNA_define_verify_sdna(1);
 
   RNA_api_workspace_tool(srna);
 }

source/blender/makesrna/intern/rna_workspace_api.c

@@ -63,7 +63,9 @@ static void rna_WorkSpaceTool_setup(ID *id,
   STRNCPY(tref_rt.op, op_idname);
   tref_rt.index = index;
 
-  STRNCPY(tref_rt.idname_fallback, idname_fallback);
+  /* While it's logical to assign both these values from setup,
+   * it's useful to stored this in DNA for re-use, exceptional case: write to the 'tref'. */
+  STRNCPY(tref->idname_fallback, idname_fallback);
   STRNCPY(tref_rt.keymap_fallback, keymap_fallback);
 
   WM_toolsystem_ref_set_from_runtime(C, (WorkSpace *)id, tref, &tref_rt, idname);

source/blender/windowmanager/intern/wm_toolsystem.c

@@ -366,7 +366,7 @@ void WM_toolsystem_ref_set_from_runtime(struct bContext *C,
     }
   }
   if (use_fallback_keymap == false) {
-    tref->runtime->idname_fallback[0] = '\0';
+    tref->idname_fallback[0] = '\0';
     tref->runtime->keymap_fallback[0] = '\0';
   }