[Discover] Add feature flag to make ESQL the default query mode

.buildkite/ftr_platform_stateful_configs.yml

@@ -92,6 +92,7 @@ enabled:
   - src/platform/test/functional/apps/discover/context_awareness/config.ts
   - src/platform/test/functional/apps/discover/observability/config.ts
   - src/platform/test/functional/apps/discover/query_mode/config.ts
+  - src/platform/test/functional/apps/discover/query_mode_esql_default/config.ts
   - src/platform/test/functional/apps/discover/tabs/config.ts
   - src/platform/test/functional/apps/discover/tabs2/config.ts
   - src/platform/test/functional/apps/discover/tabs3/config.ts

src/platform/plugins/shared/discover/public/__mocks__/services.ts

@@ -285,6 +285,7 @@ export function createDiscoverServicesMock(): DiscoverServices {
     discoverShared: discoverSharedPluginMock.createStartContract(),
     discoverFeatureFlags: {
       getCascadeLayoutEnabled: jest.fn(() => false),
+      getIsEsqlDefault: jest.fn(() => false),
     },
     embeddableEditor: {
       isByValueEditor: jest.fn(() => false),

src/platform/plugins/shared/discover/public/application/main/state_management/utils/get_initial_app_state.test.ts

@@ -489,6 +489,98 @@ describe('getInitialAppState', () => {
           });
         });
 
+        describe('when esql default is enabled', () => {
+          describe('when the query mode is unset', () => {
+            it('should return an esql initial query', () => {
+              // Given
+              const services = createDiscoverServicesMock();
+              services.storage.get = jest.fn().mockReturnValue(undefined);
+              services.uiSettings.get = jest.fn().mockReturnValue(true);
+              services.discoverFeatureFlags.getIsEsqlDefault = jest.fn(() => true);
+
+              // When
+              const appState = getInitialAppState({
+                hasGlobalState: false,
+                initialUrlState: undefined,
+                persistedTab: undefined,
+                dataView: new DataView({
+                  spec: dataViewMock.toSpec(),
+                  fieldFormats: {} as DataView['fieldFormats'],
+                }),
+                services,
+              });
+
+              // Then
+              expect(appState).toEqual(
+                expect.objectContaining({
+                  query: { esql: 'FROM the-data-view-title' },
+                })
+              );
+            });
+
+            describe('when esql uiSetting is disabled', () => {
+              it('should return the default query', () => {
+                // Given
+                const services = createDiscoverServicesMock();
+                services.storage.get = jest.fn().mockReturnValue(undefined);
+                services.uiSettings.get = jest.fn().mockReturnValue(false);
+                services.discoverFeatureFlags.getIsEsqlDefault = jest.fn(() => true);
+                services.data.query.queryString.getDefaultQuery = jest
+                  .fn()
+                  .mockReturnValue(defaultQuery);
+
+                // When
+                const appState = getInitialAppState({
+                  hasGlobalState: false,
+                  initialUrlState: undefined,
+                  persistedTab: undefined,
+                  dataView: new DataView({
+                    spec: dataViewMock.toSpec(),
+                    fieldFormats: {} as DataView['fieldFormats'],
+                  }),
+                  services,
+                });
+
+                // Then
+                expect(appState).toEqual(
+                  expect.objectContaining({
+                    query: defaultQuery,
+                  })
+                );
+              });
+            });
+
+            describe('when dataView is not a DataView instance', () => {
+              it('should return the default query', () => {
+                // Given
+                const services = createDiscoverServicesMock();
+                services.storage.get = jest.fn().mockReturnValue(undefined);
+                services.uiSettings.get = jest.fn().mockReturnValue(true);
+                services.discoverFeatureFlags.getIsEsqlDefault = jest.fn(() => true);
+                services.data.query.queryString.getDefaultQuery = jest
+                  .fn()
+                  .mockReturnValue(defaultQuery);
+
+                // When
+                const appState = getInitialAppState({
+                  hasGlobalState: false,
+                  initialUrlState: undefined,
+                  persistedTab: undefined,
+                  dataView: dataViewMock,
+                  services,
+                });
+
+                // Then
+                expect(appState).toEqual(
+                  expect.objectContaining({
+                    query: defaultQuery,
+                  })
+                );
+              });
+            });
+          });
+        });
+
         describe.each([
           { queryMode: 'esql', description: 'esql but esql is disabled' },
           { queryMode: 'classic', description: 'classic' },

src/platform/plugins/shared/discover/public/application/main/state_management/utils/get_initial_app_state.ts

@@ -105,13 +105,17 @@ function getDefaultQuery({
   if (hasGlobalState || hasInitialUrlState)
     return initialUrlState?.query || services.data.query.queryString.getDefaultQuery();
 
-  // Lastly fall back to the last selected query mode if available
-  const hasEsqlEnabled = services.uiSettings.get(ENABLE_ESQL);
-
+  // If the last query mode used by the user was classic, just return the default query
   const queryMode = services.storage.get(DISCOVER_QUERY_MODE_KEY);
-  if (hasEsqlEnabled && queryMode === 'esql' && dataView instanceof DataView)
+  if (queryMode === 'classic') return services.data.query.queryString.getDefaultQuery();
+
+  // If the last query mode used by the user was esql, or if esql is default, return the initial esql query
+  const canUseEsql = services.uiSettings.get(ENABLE_ESQL) && dataView instanceof DataView;
+  const isEsqlDefault = services.discoverFeatureFlags.getIsEsqlDefault();
+  if (canUseEsql && (queryMode === 'esql' || isEsqlDefault))
     return { esql: getInitialESQLQuery(dataView, true) };
 
+  // Lastly, fall back to classic if we can't use anything else
   return services.data.query.queryString.getDefaultQuery();
 }
 

src/platform/plugins/shared/discover/public/build_services.ts

@@ -71,7 +71,10 @@ import type { DiscoverSingleDocLocator } from './application/doc/locator';
 import type { DiscoverAppLocator } from '../common';
 import type { ProfilesManager } from './context_awareness';
 import type { DiscoverEBTManager } from './ebt_manager';
-import { CASCADE_LAYOUT_ENABLED_FEATURE_FLAG_KEY } from './constants';
+import {
+  CASCADE_LAYOUT_ENABLED_FEATURE_FLAG_KEY,
+  IS_ESQL_DEFAULT_FEATURE_FLAG_KEY,
+} from './constants';
 import { EmbeddableEditorService } from './plugin_imports/embeddable_editor_service';
 
 /**
@@ -89,6 +92,7 @@ export interface UrlTracker {
 
 export interface DiscoverFeatureFlags {
   getCascadeLayoutEnabled: () => boolean;
+  getIsEsqlDefault: () => boolean;
 }
 
 export interface DiscoverServices {
@@ -201,6 +205,8 @@ export const buildServices = ({
     discoverFeatureFlags: {
       getCascadeLayoutEnabled: () =>
         core.featureFlags.getBooleanValue(CASCADE_LAYOUT_ENABLED_FEATURE_FLAG_KEY, false),
+      getIsEsqlDefault: () =>
+        core.featureFlags.getBooleanValue(IS_ESQL_DEFAULT_FEATURE_FLAG_KEY, false),
     },
     docLinks: core.docLinks,
     embeddable: plugins.embeddable,

src/platform/plugins/shared/discover/public/constants.ts

@@ -12,3 +12,4 @@ export const ADHOC_DATA_VIEW_RENDER_EVENT = 'ad_hoc_data_view';
 export const SEARCH_SESSION_ID_QUERY_PARAM = 'searchSessionId';
 
 export const CASCADE_LAYOUT_ENABLED_FEATURE_FLAG_KEY = 'discover.cascadeLayoutEnabled';
+export const IS_ESQL_DEFAULT_FEATURE_FLAG_KEY = 'discover.isEsqlDefault';

src/platform/test/functional/apps/discover/group4/_discover_fields_api.ts

@@ -74,7 +74,7 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
       await dataGrid.clickRowToggle();
       await discover.isShowingDocViewer();
       await discover.clickDocViewerTab('doc_view_source');
-      await discover.expectSourceViewerToExist();
+      await discover.isInEsqlMode();
     });
   });
 }

src/platform/test/functional/apps/discover/query_mode/_default_query_mode.ts

@@ -16,8 +16,6 @@ export default function ({ getPageObjects, getService }: FtrProviderContext) {
     'unifiedSearch',
   ]);
 
-  const testSubjects = getService('testSubjects');
-
   describe('Default query mode', () => {
     afterEach(async () => {
       await discover.resetQueryMode();
@@ -31,7 +29,7 @@ export default function ({ getPageObjects, getService }: FtrProviderContext) {
         expect(queryMode).to.be(null);
 
         // Go to discover and validate classic mode
-        await testSubjects.existOrFail('discover-dataView-switch-link');
+        await discover.isInClassicMode();
       });
     });
 
@@ -45,7 +43,7 @@ export default function ({ getPageObjects, getService }: FtrProviderContext) {
 
         // Reload the app and validate ES|QL mode is persisted
         await common.navigateToApp('discover', { path: '' });
-        await discover.expectSourceViewerToExist();
+        await discover.isInEsqlMode();
       });
     });
 
@@ -60,7 +58,7 @@ export default function ({ getPageObjects, getService }: FtrProviderContext) {
 
         // Reload the app and validate classic mode is persisted
         await common.navigateToApp('discover', { path: '' });
-        await testSubjects.existOrFail('discover-dataView-switch-link');
+        await discover.isInClassicMode();
       });
     });
   });

src/platform/test/functional/apps/discover/query_mode_esql_default/_default_query_mode.ts

@@ -0,0 +1,65 @@
+/*
+ * 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 ({ getPageObjects, getService }: FtrProviderContext) {
+  const { discover, common, unifiedSearch } = getPageObjects([
+    'discover',
+    'common',
+    'unifiedSearch',
+  ]);
+
+  describe('Default query mode', () => {
+    afterEach(async () => {
+      await discover.resetQueryMode();
+    });
+
+    describe('when there is no default query mode set', () => {
+      it('should open Discover in ESQL mode', async () => {
+        // Validate that no default query mode is set
+        await common.navigateToApp('discover');
+        const queryMode = await discover.getQueryMode();
+        expect(queryMode).to.be(null);
+
+        // Go to discover and validate ESQL mode
+        await discover.isInEsqlMode();
+      });
+    });
+
+    describe('when the user clicks ES|QL mode', () => {
+      it('should set the default mode to ES|QL', async () => {
+        // Go to discover and select ES|QL mode
+        await common.navigateToApp('discover');
+        await unifiedSearch.switchToDataViewMode();
+        await discover.selectTextBaseLang();
+        const queryMode = await discover.getQueryMode();
+        expect(queryMode).to.contain('esql');
+
+        // Reload the app and validate ES|QL mode is persisted
+        await common.navigateToApp('discover', { path: '' });
+        await discover.isInEsqlMode();
+      });
+    });
+
+    describe('when the user clicks classic', () => {
+      it('should set the default mode to classic', async () => {
+        // Go to discover and select classic mode
+        await common.navigateToApp('discover');
+        await unifiedSearch.switchToDataViewMode();
+        const queryMode = await discover.getQueryMode();
+        expect(queryMode).to.contain('classic');
+
+        // Reload the app and validate classic mode is persisted
+        await common.navigateToApp('discover', { path: '' });
+        await discover.isInClassicMode();
+      });
+    });
+  });
+}

src/platform/test/functional/apps/discover/query_mode_esql_default/config.ts

@@ -0,0 +1,27 @@
+/*
+ * 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 type { FtrConfigProviderContext } from '@kbn/test';
+
+export default async function ({ readConfigFile }: FtrConfigProviderContext) {
+  const functionalConfig = await readConfigFile(require.resolve('../../../config.base.js'));
+  const kbnTestServer = functionalConfig.get('kbnTestServer');
+
+  return {
+    ...functionalConfig.getAll(),
+    kbnTestServer: {
+      ...kbnTestServer,
+      serverArgs: [
+        ...kbnTestServer.serverArgs,
+        '--feature_flags.overrides.discover.isEsqlDefault=true',
+      ],
+    },
+    testFiles: [require.resolve('.')],
+  };
+}

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

@@ -0,0 +1,31 @@
+/*
+ * 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 type { FtrProviderContext } from '../ftr_provider_context';
+
+export default function ({ getService, loadTestFile }: FtrProviderContext) {
+  const esArchiver = getService('esArchiver');
+  const browser = getService('browser');
+
+  describe('discover/query_mode_esql_default', function () {
+    before(async function () {
+      await esArchiver.loadIfNeeded(
+        'src/platform/test/functional/fixtures/es_archiver/logstash_functional'
+      );
+      await browser.setWindowSize(1600, 1200);
+    });
+
+    after(async function unloadMakelogs() {
+      await esArchiver.unload(
+        'src/platform/test/functional/fixtures/es_archiver/logstash_functional'
+      );
+    });
+
+    loadTestFile(require.resolve('./_default_query_mode'));
+  });
+}

src/platform/test/functional/page_objects/discover_page.ts

@@ -522,10 +522,14 @@ export class DiscoverPageObject extends FtrService {
     return this.dataGrid.clickDocViewerTab(id);
   }
 
-  public async expectSourceViewerToExist() {
+  public async isInEsqlMode() {
     return await this.find.byClassName('monaco-editor');
   }
 
+  public async isInClassicMode() {
+    return await this.testSubjects.existOrFail('discover-dataView-switch-link');
+  }
+
   public async expectDocTableToBeLoaded() {
     const renderComplete = await this.testSubjects.getAttribute(
       'discoverDocTable',