fix(gaq): make async opt-in explicit + fix per-dashboard override persistence

Address review feedback on #43429:
- async opt-in was applied inside the shared v1ChartDataRequest, so direct
  callers that read response.json.result (AlertReportModal, ViewQueryModal,
  fetchTopNValues, useResultsPane) would receive a 202 {task_ids} and break.
  Gate injection on an explicit getChartDataRequest({enableAsyncMode}) that only
  the 202-handling callers set (exploreJSON, FilterValue, FiltersConfigForm,
  DrillByModal, ChartVersionPreview).
- the dashboard properties async override was never applied when a dashboard
  already had json_metadata.async_mode: the editor copy carried it so the
  '=== undefined' guard skipped the dropdown. Omit async_mode from the Advanced
  JSON editor copy (dropdown is the sole source of truth, mirroring
  show_chart_timestamps) and apply the dropdown value unconditionally on save.

Author: villebro

superset-frontend/src/components/Chart/DrillBy/DrillByModal.tsx

@@ -405,6 +405,8 @@ export default function DrillByModal({
     const requestDrillData = () =>
       getChartDataRequest({
         formData: drilledFormData,
+        // 202 is handled below via handleChartDataResponse.
+        enableAsyncMode: true,
       });
     requestDrillData()
       .then(({ response, json }) =>
@@ -502,6 +504,8 @@ export default function DrillByModal({
       const requestDrillData = () =>
         getChartDataRequest({
           formData: drilledFormData,
+          // 202 is handled below via handleChartDataResponse.
+          enableAsyncMode: true,
         });
       requestDrillData()
         .then(({ response, json }) =>

superset-frontend/src/components/Chart/chartAction.ts

@@ -254,6 +254,9 @@ export interface RequestParams {
   // Per-dashboard async-mode override (from json_metadata.async_mode), used to
   // resolve whether this render requests async execution.
   async_mode_override?: AsyncModeOverride;
+  // Whether the caller handles an HTTP 202 async task response (see
+  // GetChartDataRequestParams.enableAsyncMode).
+  enableAsyncMode?: boolean;
   [key: string]: unknown;
 }
 
@@ -283,6 +286,11 @@ export interface GetChartDataRequestParams {
   force?: boolean;
   requestParams?: RequestParams;
   ownState?: JsonObject;
+  // Opt into asynchronous execution. Only set by callers that handle an HTTP 202
+  // task response (via handleChartDataResponse / waitForAsyncData); direct
+  // consumers that read `response.json.result` must leave this false so they keep
+  // the synchronous flow.
+  enableAsyncMode?: boolean;
 }
 
 // runAnnotationQuery params interface
@@ -449,9 +457,11 @@ const v1ChartDataRequest = async (
   }).toString();
 
   // Opt full JSON chart-data renders into async execution per the resolved policy
-  // (feature flag + deployment default + optional per-dashboard override). The
-  // server treats an absent async_mode as synchronous, so this is additive.
+  // (feature flag + deployment default + optional per-dashboard override). Only
+  // callers that handle a 202 task response set enableAsyncMode; the server treats
+  // an absent async_mode as synchronous, so this is additive.
   const asyncMode =
+    requestParams.enableAsyncMode === true &&
     resultFormat === 'json' &&
     resultType === 'full' &&
     resolveAsyncMode(requestParams.async_mode_override);
@@ -480,9 +490,11 @@ export async function getChartDataRequest({
   force = false,
   requestParams = {},
   ownState = {},
+  enableAsyncMode = false,
 }: GetChartDataRequestParams): Promise<ChartDataRequestResponse> {
   let querySettings: RequestParams = {
     ...requestParams,
+    enableAsyncMode,
   };
 
   if (domainShardingEnabled) {
@@ -743,6 +755,8 @@ export function exploreJSON(
         force: fromCache ? false : force,
         requestParams,
         ownState,
+        // exploreJSON handles 202 via handleChartDataResponse.
+        enableAsyncMode: true,
       });
 
     const chartDataRequest = requestChartData();

superset-frontend/src/dashboard/components/PropertiesModal/index.tsx

@@ -209,6 +209,9 @@ const PropertiesModal = ({
         'map_label_colors',
         'color_scheme_domain',
         'show_chart_timestamps',
+        // Edited via the async-mode dropdown, not the raw JSON editor, so the
+        // dropdown is the single source of truth (mirrors show_chart_timestamps).
+        'async_mode',
       ]);
 
       setJsonMetadata(metaDataCopy ? jsonStringify(metaDataCopy) : '');
@@ -357,14 +360,13 @@ const PropertiesModal = ({
     // refresh") rather than falling through to the dropdown value (#42116).
     jsonMetadataObj.refresh_frequency =
       jsonMetadataObj.refresh_frequency ?? refreshFrequency;
-    // Persist the per-dashboard async override (unless set directly in the
-    // Advanced JSON editor). 'default' clears it so the deployment default applies.
-    if (jsonMetadataObj.async_mode === undefined) {
-      if (asyncMode === 'default') {
-        delete jsonMetadataObj.async_mode;
-      } else {
-        jsonMetadataObj.async_mode = asyncMode;
-      }
+    // Persist the per-dashboard async override from the dropdown (the sole source
+    // of truth — async_mode is omitted from the Advanced JSON editor). 'default'
+    // clears it so the deployment default applies.
+    if (asyncMode === 'default') {
+      delete jsonMetadataObj.async_mode;
+    } else {
+      jsonMetadataObj.async_mode = asyncMode;
     }
     jsonMetadataObj.show_chart_timestamps = Boolean(showChartTimestamps);
     const customLabelColors = jsonMetadataObj.label_colors || {};

superset-frontend/src/dashboard/components/nativeFilters/FilterBar/FilterControls/FilterValue.tsx

@@ -283,6 +283,8 @@ const FilterValue: FC<FilterValueProps> = ({
           formData: newFormData,
           force: fromCache ? false : shouldRefresh,
           ownState: filterOwnState,
+          // 202 is handled below via waitForAsyncData.
+          enableAsyncMode: true,
         });
       requestFilterData()
         .then(({ response, json }) => {

superset-frontend/src/dashboard/components/nativeFilters/FiltersConfigModal/FiltersConfigForm/FiltersConfigForm.tsx

@@ -530,6 +530,8 @@ const FiltersConfigForm = (
         getChartDataRequest({
           formData,
           force: fromCache ? false : force,
+          // 202 is handled below via waitForAsyncData.
+          enableAsyncMode: true,
         });
       requestDefaultValues()
         .then(({ response, json }) => {

superset-frontend/src/features/versionHistory/ChartVersionPreview.tsx

@@ -181,6 +181,8 @@ export default function ChartVersionPreview() {
       const requestPreviewData = () =>
         getChartDataRequest({
           formData: previewFormData,
+          // 202 is handled below via handleChartDataResponse.
+          enableAsyncMode: true,
         });
       const { response, json } = await requestPreviewData();
       const result = await handleChartDataResponse(