🔨 Renamed CantHaveMultipleOutputs for less confusion.

Author: T4rk1n

dash/dash.py

@@ -795,7 +795,7 @@ def duplicate_check():
                     output.component_id,
                     output.component_property
                 ).replace('    ', '')
-            raise exceptions.CantHaveMultipleOutputs(msg)
+            raise exceptions.DuplicateCallbackOutput(msg)
 
     def _validate_callback_output(self, output_value, output):
         valid = [str, dict, int, float, type(None), Component]

dash/exceptions.py

@@ -51,6 +51,11 @@ class CantHaveMultipleOutputs(CallbackException):
     pass
 
 
+# Renamed for less confusion with multi output.
+class DuplicateCallbackOutput(CantHaveMultipleOutputs):
+    pass
+
+
 class PreventUpdate(CallbackException):
     pass
 

tests/test_integration.py

@@ -12,7 +12,7 @@
 import dash
 
 from dash.dependencies import Input, Output, State
-from dash.exceptions import PreventUpdate, CantHaveMultipleOutputs
+from dash.exceptions import PreventUpdate, DuplicateCallbackOutput
 from .IntegrationTests import IntegrationTests
 from .utils import assert_clean_console, invincible, wait_for
 
@@ -562,7 +562,7 @@ def on_click(n_clicks, n_clicks_timestamp):
 
             return n_clicks, n_clicks_timestamp
 
-        # Dummy callback for CantHaveMultipleOutputs
+        # Dummy callback for DuplicateCallbackOutput test.
         @app.callback(Output('output3', 'children'),
                       [Input('output-btn', 'n_clicks')])
         def dummy_callback(n_clicks):
@@ -572,7 +572,7 @@ def dummy_callback(n_clicks):
             return 'Output 3: {}'.format(n_clicks)
 
         # Test that a multi output can't be included in a single output
-        with self.assertRaises(CantHaveMultipleOutputs) as context:
+        with self.assertRaises(DuplicateCallbackOutput) as context:
             @app.callback(Output('output1', 'children'),
                           [Input('output-btn', 'n_clicks')])
             def on_click_duplicate(n_clicks):
@@ -584,7 +584,7 @@ def on_click_duplicate(n_clicks):
         self.assertTrue('output1' in context.exception.args[0])
 
         # Test a multi output cannot contain a used single output
-        with self.assertRaises(CantHaveMultipleOutputs) as context:
+        with self.assertRaises(DuplicateCallbackOutput) as context:
             @app.callback([Output('output3', 'children'),
                            Output('output4', 'children')],
                           [Input('output-btn', 'n_clicks')])