improve laggy subset finalization (#3175)

* only call subset_selected_changed_callback for matching subset updates
* optimize handling subset_state changes
* prevent unnecessary state-update
* avoid (some cases of) startswith since can be expensive on some machines

jdaviz/app.py

@@ -610,7 +610,7 @@ def _on_layers_changed(self, msg):
                 self.state.layer_icons = {
                     **self.state.layer_icons,
                     layer_name: alpha_index(len([ln for ln, ic in self.state.layer_icons.items()
-                                                 if not ic.startswith('mdi-') and
+                                                 if not ic[:4] == 'mdi-' and
                                                  self._get_assoc_data_parent(ln) is None]))
                 }
 
@@ -621,12 +621,14 @@ def _on_layers_changed(self, msg):
             if children_layers is not None:
                 parent_icon = self.state.layer_icons[layer_name]
                 for i, child_layer in enumerate(children_layers, start=1):
-                    child_layer_icons[child_layer] = f'{parent_icon}{i}'
+                    if child_layer not in self.state.layer_icons:
+                        child_layer_icons[child_layer] = f'{parent_icon}{i}'
 
-        self.state.layer_icons = {
-            **self.state.layer_icons,
-            **child_layer_icons
-        }
+        if child_layer_icons:
+            self.state.layer_icons = {
+                **self.state.layer_icons,
+                **child_layer_icons
+            }
 
     def _change_reference_data(self, new_refdata_label, viewer_id=None):
         """

jdaviz/configs/cubeviz/plugins/spectral_extraction/spectral_extraction.py

@@ -252,8 +252,9 @@ def _aperture_items_changed(self, msg):
             return
         if not hasattr(self, 'aperture'):
             return
+        orig_labels = [item['label'] for item in msg['old']]
         for item in msg['new']:
-            if item not in msg['old']:
+            if item['label'] not in orig_labels:
                 if item.get('type') != 'spatial':
                     continue
                 subset_lbl = item.get('label')

jdaviz/core/template_mixin.py

@@ -1936,14 +1936,14 @@ def _update_subset(self, subset, attribute=None):
              or (subset.label == self.selected))):
             # updated the currently selected subset, clear all cache
             self._clear_cache()
-            update_has_subregions = True
+            selected_has_changed = True
         else:
-            update_has_subregions = False
+            selected_has_changed = False
 
         if subset.label not in self.labels:
             # NOTE: this logic will need to be revisited if generic renaming of subsets is added
             # see https://github.com/spacetelescope/jdaviz/pull/1175#discussion_r829372470
-            if subset.label.startswith('Subset') and self._is_valid_item(subset):
+            if subset.label[:6] == 'Subset' and self._is_valid_item(subset):
                 # NOTE: += will not trigger traitlet update
                 self.items = self.items + [self._subset_to_dict(subset)]  # noqa
         else:
@@ -1958,11 +1958,11 @@ def _update_subset(self, subset, attribute=None):
                               else self._subset_to_dict(subset)
                               for s in self.items]
 
-        if update_has_subregions:
+        if selected_has_changed:
             self._update_has_subregions()
 
-        if self._subset_selected_changed_callback is not None:
-            self._subset_selected_changed_callback()
+            if self._subset_selected_changed_callback is not None:
+                self._subset_selected_changed_callback()
 
     def _update_has_subregions(self):
         if "selected_has_subregions" in self._plugin_traitlets.keys():