fix a few menu related bugs

Author: gbeane

src/jabs/ui/main_window/main_window.py

@@ -84,6 +84,7 @@ def __init__(self, app_name: str, app_name_long: str, *args, **kwargs) -> None:
         self._app_name = app_name
         self._app_name_long = app_name_long
         self._project = None
+        self._previous_project = None
         self._project_loader_thread = None
         self._progress_dialog = None
         self._pool_warm_thread = None
@@ -255,15 +256,13 @@ def open_project(self, project_path: str) -> None:
         self._progress_dialog = create_progress_dialog(self, "Loading Project...", 0)
         self._progress_dialog.show()
 
-        # Shut down old project executor if needed
-        if self._project is not None:
-            try:
-                self._project.shutdown_executor()
-            except Exception as e:
-                print(
-                    f"Warning: failed to shut down executor for old project: {e}", file=sys.stderr
-                )
-            self._project = None
+        # Save reference to current project in case the new project load fails
+        # We'll restore it so the user can continue working
+        # Don't shut down its executor yet - only do that if the new project loads successfully
+        self._previous_project = self._project
+
+        # Clear the current project reference while loading
+        self._project = None
 
         session_tracking_enabled = bool(
             self._settings.value(SESSION_TRACKING_ENABLED_KEY, False, type=bool)
@@ -356,6 +355,19 @@ def _project_loaded_callback(self) -> None:
         self._project = self._project_loader_thread.project
         self._project_loader_thread = None
 
+        # Shut down the previous project's executor now that the new project loaded successfully
+        if self._previous_project is not None:
+            try:
+                self._previous_project.shutdown_executor()
+            except Exception as e:
+                print(
+                    f"Warning: failed to shut down executor for previous project: {e}",
+                    file=sys.stderr,
+                )
+
+        # Clear the previous project reference since new project loaded successfully
+        self._previous_project = None
+
         # The central_widget updates main_control_widget
         self._central_widget.set_project(self._project)
         self.video_list.set_project(self._project)
@@ -431,6 +443,13 @@ def _project_load_error_callback(self, error: Exception) -> None:
         self._progress_dialog.close()
         self._progress_dialog.deleteLater()
         self._progress_dialog = None
+
+        # Restore the previous project so the user can continue working
+        # (If there was no previous project, self._project will remain None)
+        if self._previous_project:
+            self._project = self._previous_project
+            self._previous_project = None
+
         QtWidgets.QMessageBox.critical(self, "Error loading project", str(error))
 
     def show_license_dialog(self) -> QtWidgets.QDialog.DialogCode:

src/jabs/ui/main_window/menu_handlers.py

@@ -109,6 +109,14 @@ def archive_behavior_callback(self, behavior: str) -> None:
 
     def show_project_pruning_dialog(self) -> None:
         """Open dialog to prune videos without labels from the project."""
+        if self.window._project is None:
+            QtWidgets.QMessageBox.warning(
+                self.window,
+                "No Project Loaded",
+                "Please load a project before attempting to prune videos.",
+            )
+            return
+
         prune_dialog = ProjectPruningDialog(self.window._project, parent=self.window)
         if prune_dialog.exec() == QtWidgets.QDialog.DialogCode.Accepted:
             # Get the videos to delete from the dialog