fix(chart-controls): clear stale custom time-shift date error on shift change

The "Shift start date" control (start_date_offset) in the shared Time
Comparison section raises an "A date is required when using custom date shift"
validation error via mapStateToProps when Time shift is "Custom date" and the
date is empty. Because the control did not declare validationDependencies on
time_compare, exploreReducer's SET_FIELD_VALUE never re-ran its mapStateToProps
when the user switched Time shift to another preset, so the stale error
survived in Redux state and blocked further chart updates until a page refresh.

Add validationDependencies: ['time_compare'] so the control re-validates
whenever Time shift changes, mirroring the existing row_limit/server_pagination
pattern. Add a reducer-level regression test covering the clear-then-switch
sequence.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

superset-frontend/packages/superset-ui-chart-controls/src/sections/timeComparison.tsx

@@ -122,6 +122,12 @@ export const timeComparisonControls: ({
             }
             return newState;
           },
+          // Re-run this control's validation whenever `time_compare` changes so
+          // the "date required" error clears once a non-custom shift is picked.
+          // Without it the stale error survives in Redux (see the
+          // dependantControls path in exploreReducer's SET_FIELD_VALUE handler)
+          // and blocks further chart updates until a page refresh.
+          validationDependencies: ['time_compare'],
         },
       },
     ],

superset-frontend/src/explore/reducers/exploreReducer.test.ts

@@ -17,9 +17,11 @@
  * under the License.
  */
 
-import exploreReducer, { ExploreState } from './exploreReducer';
-import { setStashFormData } from '../actions/exploreActions';
 import { QueryFormData } from '@superset-ui/core';
+import { sections, CustomControlItem } from '@superset-ui/chart-controls';
+import { getControlStateFromControlConfig } from 'src/explore/controlUtils';
+import exploreReducer, { ExploreState } from './exploreReducer';
+import { setControlValue, setStashFormData } from '../actions/exploreActions';
 
 test('reset hiddenFormData on SET_STASH_FORM_DATA', () => {
   const initialState: ExploreState = {
@@ -52,3 +54,72 @@ test('skips updates when the field is already updated on SET_STASH_FORM_DATA', (
   const newState = exploreReducer(initialState, restoreAction);
   expect(newState).toBe(initialState);
 });
+
+// Regression guard for the shared Time Comparison section (used by the Table
+// chart, among others): selecting "Custom date" for Time shift and then
+// clearing "Shift start date" raises a required-date validation error. When the
+// user then switches Time shift to a non-custom preset the error must clear.
+// Because `start_date_offset` did not declare `validationDependencies` on
+// `time_compare`, SET_FIELD_VALUE never re-ran its mapStateToProps and the stale
+// error survived in Redux, blocking further chart updates until a page refresh.
+test('SET_FIELD_VALUE clears the custom-shift date error when time_compare leaves "custom"', () => {
+  const REQUIRED_DATE_ERROR = 'A date is required when using custom date shift';
+  const timeComparisonSection = sections.timeComparisonControls({
+    multi: false,
+    showCalculationType: false,
+    showFullChoices: false,
+  });
+  const timeCompareConfig = (
+    timeComparisonSection.controlSetRows[0][0] as CustomControlItem
+  ).config;
+  const startDateOffsetConfig = (
+    timeComparisonSection.controlSetRows[1][0] as CustomControlItem
+  ).config;
+
+  const form_data = {
+    time_compare: 'custom',
+    start_date_offset: '2021-01-01',
+  } as unknown as QueryFormData;
+
+  // Build the control states the way the explore store does so they carry the
+  // real mapStateToProps / validationDependencies from the control config.
+  const controlPanelState = { controls: {}, form_data };
+  const initialState: ExploreState = {
+    form_data,
+    controls: {
+      time_compare: getControlStateFromControlConfig(
+        timeCompareConfig,
+        controlPanelState,
+        'custom',
+      )!,
+      start_date_offset: getControlStateFromControlConfig(
+        startDateOffsetConfig,
+        controlPanelState,
+        '2021-01-01',
+      )!,
+    },
+  };
+
+  // A valid custom date starts without a validation error.
+  expect(initialState.controls.start_date_offset.validationErrors).toEqual([]);
+
+  // 1) Clearing "Shift start date" raises the required-date error (expected).
+  const afterClear = exploreReducer(
+    initialState,
+    setControlValue('start_date_offset', '') as Parameters<
+      typeof exploreReducer
+    >[1],
+  );
+  expect(afterClear.controls.start_date_offset.validationErrors).toEqual([
+    REQUIRED_DATE_ERROR,
+  ]);
+
+  // 2) Switching Time shift to a non-custom preset must clear the stale error.
+  const afterSwitch = exploreReducer(
+    afterClear,
+    setControlValue('time_compare', '1 week ago') as Parameters<
+      typeof exploreReducer
+    >[1],
+  );
+  expect(afterSwitch.controls.start_date_offset.validationErrors).toEqual([]);
+});