widgets.status: disable 'Revert Unstaged Edits' when nothing is selected

Prevent the 'Revert Unstaged Edits...' action from being used when there
is nothing to revert.  This ensures that the hotkey does not activate
when there is nothing to do.

Signed-off-by: David Aguilar <davvid@gmail.com>

Author: davvid

cola/widgets/status.py

@@ -336,6 +336,13 @@ def _updated(self):
         self.restore_selection()
         self.restore_scrollbar()
         self.update_column_widths()
+        self.update_actions()
+
+    def update_actions(self, selected=None):
+        if selected is None:
+            selected = selection.selection()
+        can_revert_unstaged_edits = bool(selected.staged or selected.modified)
+        self.revert_unstaged_edits_action.setEnabled(can_revert_unstaged_edits)
 
     def set_staged(self, items):
         """Adds items to the 'Staged' subtree."""
@@ -770,7 +777,10 @@ def _open_parent_dir(self):
     def show_selection(self):
         """Show the selected item."""
         # Sync the selection model
-        selection.selection_model().set_selection(self.selection())
+        selected = self.selection()
+        selection.selection_model().set_selection(selected)
+        self.update_actions(selected=selected)
+
         selected_indexes = self.selected_indexes()
         if not selected_indexes:
             if self.m.amending():