[Discover] Fix ES|QL embeddable without data view spec failing to load (#241217)

## Summary

This PR fixes an issue where adding an ES|QL based Discover session
without an ad hoc data view spec as a dashboard panel fails. Instead, it
now checks for an ad hoc data view in ES|QL tabs, and generates one from
the query if none exists (similar to Discover itself).

Fixes #241218.

### Checklist

- [ ] Any text added follows [EUI's writing
guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/src/platform/packages/shared/kbn-i18n/README.md)
- [ ]
[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials
- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [ ] If a plugin configuration key changed, check if it needs to be
allowlisted in the cloud and added to the [docker
list](https://github.com/elastic/kibana/blob/main/src/dev/build/tasks/os_packages/docker_generator/resources/base/bin/kibana-docker)
- [x] This was checked for breaking HTTP API changes, and any breaking
changes have been approved by the breaking-change committee. The
`release_note:breaking` label should be applied in these situations.
- [x] [Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed
- [x] The PR description includes the appropriate Release Notes section,
and the correct `release_note:*` label is applied per the
[guidelines](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)
- [x] Review the [backport
guidelines](https://docs.google.com/document/d/1VyN5k91e5OVumlc0Gb9RPa3h1ewuPE705nRtioPiTvY/edit?usp=sharing)
and apply applicable `backport:*` labels.

Author: davismcphee

src/platform/plugins/shared/discover/public/embeddable/initialize_search_embeddable_api.tsx

@@ -24,7 +24,12 @@ import type { DiscoverGridSettings, SavedSearch } from '@kbn/saved-search-plugin
 import type { SortOrder, VIEW_MODE } from '@kbn/saved-search-plugin/public';
 import type { DataGridDensity, DataTableColumnsMeta } from '@kbn/unified-data-table';
 
-import type { AggregateQuery, Filter, Query } from '@kbn/es-query';
+import {
+  isOfAggregateQueryType,
+  type AggregateQuery,
+  type Filter,
+  type Query,
+} from '@kbn/es-query';
 import type { DiscoverServices } from '../build_services';
 import { EDITABLE_SAVED_SEARCH_KEYS } from '../../common/embeddable/constants';
 import { getSearchEmbeddableDefaults } from './get_search_embeddable_defaults';
@@ -34,17 +39,25 @@ import type {
   SearchEmbeddableSerializedAttributes,
   SearchEmbeddableStateManager,
 } from './types';
+import { getEsqlDataView } from '../application/main/state_management/utils/get_esql_data_view';
 
 const initializeSearchSource = async (
-  dataService: DiscoverServices['data'],
+  discoverServices: DiscoverServices,
   serializedSearchSource?: SerializedSearchSourceFields
 ) => {
   const [searchSource, parentSearchSource] = await Promise.all([
-    dataService.search.searchSource.create(serializedSearchSource),
-    dataService.search.searchSource.create(),
+    discoverServices.data.search.searchSource.create(serializedSearchSource),
+    discoverServices.data.search.searchSource.create(),
   ]);
+
   searchSource.setParent(parentSearchSource);
-  const dataView = searchSource.getField('index');
+
+  const query = searchSource.getField('query');
+  let dataView = searchSource.getField('index');
+
+  if (isOfAggregateQueryType(query)) {
+    dataView = await getEsqlDataView(query, dataView, discoverServices);
+  }
 
   return { searchSource, dataView };
 };
@@ -84,7 +97,7 @@ export const initializeSearchEmbeddableApi = async (
 }> => {
   /** We **must** have a search source, so start by initializing it  */
   const { searchSource, dataView } = await initializeSearchSource(
-    discoverServices.data,
+    discoverServices,
     initialState.serializedSearchSource
   );
   const searchSource$ = new BehaviorSubject<ISearchSource>(searchSource);

src/platform/test/functional/apps/discover/embeddable/_esql_embeddable.ts

@@ -0,0 +1,55 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+import expect from '@kbn/expect';
+import type { FtrProviderContext } from '../ftr_provider_context';
+
+export default function ({ getService, getPageObjects }: FtrProviderContext) {
+  const dataGrid = getService('dataGrid');
+  const dashboardAddPanel = getService('dashboardAddPanel');
+  const filterBar = getService('filterBar');
+  const esArchiver = getService('esArchiver');
+  const kibanaServer = getService('kibanaServer');
+  const { dashboard, header, timePicker } = getPageObjects(['dashboard', 'header', 'timePicker']);
+
+  describe('discover ES|QL embeddable', () => {
+    before(async () => {
+      await esArchiver.loadIfNeeded(
+        'src/platform/test/functional/fixtures/es_archiver/logstash_functional'
+      );
+      await kibanaServer.importExport.load(
+        'src/platform/test/functional/fixtures/kbn_archiver/discover'
+      );
+      await timePicker.setDefaultAbsoluteRangeViaUiSettings();
+    });
+
+    after(async () => {
+      await timePicker.resetDefaultAbsoluteRangeViaUiSettings();
+      await kibanaServer.importExport.unload(
+        'src/platform/test/functional/fixtures/kbn_archiver/discover'
+      );
+      await kibanaServer.savedObjects.cleanStandardList();
+    });
+
+    beforeEach(async () => {
+      await dashboard.navigateToApp();
+      await filterBar.ensureFieldEditorModalIsClosed();
+      await dashboard.gotoDashboardLandingPage();
+      await dashboard.clickNewDashboard();
+    });
+
+    it('should add an ES|QL based Discover session panel to a dashboard', async () => {
+      await dashboardAddPanel.addSavedSearch('ES|QL Discover Session');
+      await header.waitUntilLoadingHasFinished();
+      await dashboard.waitForRenderComplete();
+      await dashboard.verifyNoRenderErrors();
+      expect(await dataGrid.getDocCount()).to.be(1000);
+    });
+  });
+}

src/platform/test/functional/apps/discover/embeddable/index.ts

@@ -27,5 +27,6 @@ export default function ({ getService, loadTestFile }: FtrProviderContext) {
     loadTestFile(require.resolve('./_saved_search_embeddable'));
     loadTestFile(require.resolve('./multiple_data_views'));
     loadTestFile(require.resolve('./_log_stream_embeddable.ts'));
+    loadTestFile(require.resolve('./_esql_embeddable.ts'));
   });
 }

src/platform/test/functional/fixtures/kbn_archiver/discover.json

@@ -49,3 +49,36 @@
   "type": "search",
   "version": "WzUsMl0="
 }
+
+{
+  "id": "15ba60d9-a202-49f4-aabe-b9b97efe9a32",
+  "type": "search",
+  "version": "WzExLDFd",
+  "attributes": {
+    "title": "ES|QL Discover Session",
+    "description": "ES|QL Discover Session Description",
+    "tabs": [
+      {
+        "id": "c94f57e3-dc37-4a78-8f5b-17269f479b0e",
+        "label": "Untitled",
+        "attributes": {
+          "columns": [],
+          "isTextBasedQuery": true,
+          "timeRestore": false,
+          "kibanaSavedObjectMeta": {
+            "searchSourceJSON": "{\"query\":{\"esql\":\"FROM logstash-* | SORT @timestamp desc | LIMIT 1000\"},\"filter\":[]}"
+          },
+          "sort": [
+            [
+              "@timestamp",
+              "desc"
+            ]
+          ]
+        }
+      }
+    ]
+  },
+  "references": [],
+  "coreMigrationVersion": "8.8.0",
+  "typeMigrationVersion": "10.9.0"
+}