Persist undo/redo history correctly across OpenShot sessions (OpenSho…

…t#2474)

* Updating default history limit to 15 items (for new users)
* Remove "discard history" logic, since we now want to persist it between sessions
* Correctly remove "history" attribute from undo/redo data (since history is a huge data set of undo/redo actions). Also, do not save or load update actions of type "load". Also clear actionHistory when loading a new project. These changes should prevent the OSP project file from becoming HUGE. At most, 15 changes in the undo and redo history should only increase file size by 100k or less (which I think is a fair trade off).
* Do not clear redo history if "ignore_history" is true
* Only clear redo history when a non-history update is performed

src/classes/project_data.py

@@ -339,10 +339,6 @@ def load(self, file_path):
             # Check if paths are all valid
             self.check_if_paths_are_valid()
 
-            # Discard history
-            log.info("Discarding history")
-            self._data["history"] = { "undo": [], "redo": [] }
-
             # Copy any project thumbnails to main THUMBNAILS folder
             loaded_project_folder = os.path.dirname(self.current_filepath)
             project_thumbnails_folder = os.path.join(loaded_project_folder, "thumbnail")
@@ -703,10 +699,6 @@ def save(self, file_path, move_temp_files=True, make_paths_relative=True):
         if make_paths_relative:
             self.convert_paths_to_relative(file_path)
 
-        # Discard history
-        log.info("Discarding history")
-        self._data["history"] = { "undo": [], "redo": [] }
-
         # Append version info
         v = openshot.GetVersion()
         self._data["version"] = { "openshot-qt" : info.VERSION,

src/classes/updates.py

@@ -79,9 +79,15 @@ def json(self, is_array=False, only_value=False):
                          "partial": self.partial_update,
                          "old_values": copy.deepcopy(self.old_values)}
 
-        # Always remove 'history' key (if found)
-        if "history" in data_dict:
-            data_dict.pop("history")
+        # Always remove 'history' key (if found). This prevents nested "history"
+        # attributes when a project dict is loaded.
+        try:
+            if data_dict.get("value") and "history" in data_dict.get("value"):
+                data_dict.get("value").pop("history", None)
+            if data_dict.get("old_values") and "history" in data_dict.get("old_values"):
+                data_dict.get("old_values").pop("history", None)
+        except Exception:
+            log.info('Warning: failed to clear history attribute from undo/redo data.')
 
         if not is_array:
             # Use a JSON Object as the root object
@@ -106,6 +112,16 @@ def load_json(self, value):
         self.old_values = update_action_dict.get("old_values")
         self.partial_update = update_action_dict.get("partial")
 
+        # Always remove 'history' key (if found). This prevents nested "history"
+        # attributes when a project dict is loaded.
+        try:
+            if self.values and "history" in self.values:
+                self.values.pop("history", None)
+            if self.old_values and "history" in self.old_values:
+                self.old_values.pop("history", None)
+        except Exception:
+            log.info('Warning: failed to clear history attribute from undo/redo data.')
+
 
 class UpdateManager:
     """ This class is used to track and distribute changes to listeners. Typically, only 1 instance of this class is needed,
@@ -130,14 +146,14 @@ def load_history(self, project):
 
         # Loop through each, and load serialized data into updateAction objects
         for actionDict in history.get("redo", []):
-            if "history" not in actionDict.keys():
-                action = UpdateAction()
-                action.load_json(json.dumps(actionDict))
+            action = UpdateAction()
+            action.load_json(json.dumps(actionDict))
+            if action.type != "load":
                 self.redoHistory.append(action)
         for actionDict in history.get("undo", []):
-            if "history" not in actionDict.keys():
-                action = UpdateAction()
-                action.load_json(json.dumps(actionDict))
+            action = UpdateAction()
+            action.load_json(json.dumps(actionDict))
+            if action.type != "load":
                 self.actionHistory.append(action)
 
         # Notify watchers of new status
@@ -151,9 +167,11 @@ def save_history(self, project, history_length):
         # Loop through each, and serialize
         history_length_int = int(history_length)
         for action in self.redoHistory[-history_length_int:]:
-            redo_list.append(json.loads(action.json()))
+            if action.type != "load":
+                redo_list.append(json.loads(action.json()))
         for action in self.actionHistory[-history_length_int:]:
-            undo_list.append(json.loads(action.json()))
+            if action.type != "load":
+                undo_list.append(json.loads(action.json()))
 
         # Set history data in project
         self.ignore_history = True
@@ -274,6 +292,7 @@ def load(self, values):
 
         self.last_action = UpdateAction('load', '', values)
         self.redoHistory.clear()
+        self.actionHistory.clear()
         self.dispatch_action(self.last_action)
 
     # Perform new actions, clearing redo history for taking a new path
@@ -290,7 +309,9 @@ def update(self, key, values, partial_update=False):
         """ Update the UpdateManager with an UpdateAction (this action will then be distributed to all listeners) """
 
         self.last_action = UpdateAction('update', key, values, partial_update)
-        self.redoHistory.clear()
+        if self.last_action.key and self.last_action.key[0] != "history":
+            # Clear redo history for any update except a "history" update
+            self.redoHistory.clear()
         if not self.ignore_history:
             self.actionHistory.append(self.last_action)
         self.dispatch_action(self.last_action)

src/settings/_default.settings

@@ -220,7 +220,7 @@
     "category": "Autosave",
     "min": 0,
     "setting": "history-limit",
-    "value": 20,
+    "value": 15,
     "type": "spinner-int"
   },
   {