Merge pull request jupyter-widgets#3486 from meeseeksmachine/auto-bac…

…kport-of-pr-3484-on-7.x Backport PR jupyter-widgets#3484 on branch 7.x (Check self.keys before accessing trait in set_state())
jasongrout · Jun 11, 2022 · 7665944 · 7665944
2 parents 32a2d68 + 4ec8dee
commit 7665944
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Showing 2 changed files with 4 additions and 4 deletions.
diff --git a/ipywidgets/widgets/tests/test_set_state.py b/ipywidgets/widgets/tests/test_set_state.py
@@ -308,8 +308,8 @@ class ValueWidget(Widget):
     assert widget.value == 1
 
     widget._send = mock.MagicMock()
-    # this mimics a value coming from the front end
-    widget.set_state({'value': 42})
+    # this mimics a state coming from the front end
+    widget.set_state({'value': 42, 'unexpected_field': 43})
     assert widget.value == 42
 
     # we expect this to be echoed

diff --git a/ipywidgets/widgets/widget.py b/ipywidgets/widgets/widget.py
@@ -602,8 +602,8 @@ def set_state(self, sync_data):
         # Send an echo update message immediately
         if JUPYTER_WIDGETS_ECHO:
             echo_state = {}
-            for attr,value in sync_data.items():
-                if self.trait_metadata(attr, 'echo_update', default=True):
+            for attr, value in sync_data.items():
+                if attr in self.keys and self.trait_metadata(attr, 'echo_update', default=True):
                     echo_state[attr] = value
             if echo_state:
                 echo_state, echo_buffer_paths, echo_buffers = _remove_buffers(echo_state)