Merge pull request #2700 from plotly/fix/dynamic-callback-inputmap

Fix dynamic callbacks reset graphs.

Author: alexcjohnson

dash/dash-renderer/src/APIController.react.js

@@ -166,7 +166,7 @@ function storeEffect(props, events, setErrorLoading) {
             );
         } else if (
             dependenciesRequest.status === STATUS.OK &&
-            isEmpty(graphs)
+            (isEmpty(graphs) || graphs.reset)
         ) {
             dispatch(
                 setGraphs(

dash/dash-renderer/src/actions/requestDependencies.ts

@@ -3,9 +3,10 @@ import {setGraphs} from './index';
 import apiThunk from './api';
 
 export function requestDependencies() {
-    return (dispatch: any) => {
+    return (dispatch: any, getState: any) => {
         batch(() => {
-            dispatch(setGraphs({}));
+            const {graphs} = getState();
+            dispatch(setGraphs({...graphs, reset: true}));
             dispatch(
                 apiThunk('_dash-dependencies', 'GET', 'dependenciesRequest')
             );

tests/integration/callbacks/test_dynamic_callback.py

@@ -42,3 +42,34 @@ def on_click2(n_clicks2):
 
     dash_duo.wait_for_element("#dynamic").click()
     dash_duo.wait_for_text_to_equal("#output-2", "Dynamic clicks 2")
+
+
+def test_dync002_dynamic_callback_without_element(dash_duo):
+    app = Dash()
+
+    app.layout = html.Div(
+        [
+            html.Button("Add callbacks", id="add-callbacks"),
+            html.Div(id="output"),
+        ]
+    )
+
+    @app.callback(
+        Output("output", "children"),
+        Input("add-callbacks", "n_clicks"),
+        _allow_dynamic_callbacks=True,
+        prevent_initial_call=True,
+    )
+    def on_add_callback(_):
+        @app.callback(Output("no-exist", "children"), Input("invalid", "n_clicks"))
+        def addition(_):
+            return "additional"
+
+        return html.Div("add callbacks")
+
+    dash_duo.start_server(app)
+
+    dash_duo.wait_for_element("#add-callbacks").click()
+    dash_duo.wait_for_text_to_equal("#output", "add callbacks")
+
+    assert dash_duo.get_logs() == []