perf: only add notifiers when they exist

ipython · Sep 14, 2022 · aa23cc0 · aa23cc0
1 parent 7ad779a
commit aa23cc0
Showing 1 changed file with 10 additions and 8 deletions.
diff --git a/traitlets/traitlets.py b/traitlets/traitlets.py
@@ -1414,14 +1414,16 @@ def _notify_observers(self, event):
         name, type = event.name, event.type
 
         callables = []
-        callables.extend(self._trait_notifiers.get(name, {}).get(type, []))
-        callables.extend(self._trait_notifiers.get(name, {}).get(All, []))
-        callables.extend(
-            self._trait_notifiers.get(All, {}).get(type, [])  # type:ignore[call-overload]
-        )
-        callables.extend(
-            self._trait_notifiers.get(All, {}).get(All, [])  # type:ignore[call-overload]
-        )
+        if name in self._trait_notifiers:
+            callables.extend(self._trait_notifiers.get(name, {}).get(type, []))
+            callables.extend(self._trait_notifiers.get(name, {}).get(All, []))
+        if All in self._trait_notifiers:
+            callables.extend(
+                self._trait_notifiers.get(All, {}).get(type, [])  # type:ignore[call-overload]
+            )
+            callables.extend(
+                self._trait_notifiers.get(All, {}).get(All, [])  # type:ignore[call-overload]
+            )
 
         # Now static ones
         magic_name = "_%s_changed" % name