Explore: Remove legend formatting when switching from panel to Explore (#25848)

* Remove legend formatting when switching from panel to explore

* Add test coverage

public/app/core/utils/explore.test.ts

@@ -11,6 +11,8 @@ import {
   sortLogsResult,
   SortOrder,
   updateHistory,
+  getExploreUrl,
+  GetExploreUrlArguments,
 } from './explore';
 import store from 'app/core/store';
 import {
@@ -174,6 +176,32 @@ describe('state functions', () => {
   });
 });
 
+describe('getExploreUrl', () => {
+  const args = ({
+    panel: {
+      getSavedId: () => 1,
+    },
+    panelTargets: [{ refId: 'A', expr: 'query1', legendFormat: 'legendFormat1' }],
+    panelDatasource: {
+      name: 'testDataSource',
+      meta: {
+        id: '1',
+      },
+    },
+    datasourceSrv: {
+      get: jest.fn(),
+      getDataSourceById: jest.fn(),
+    },
+    timeSrv: {
+      timeRangeForUrl: () => '1',
+    },
+  } as unknown) as GetExploreUrlArguments;
+
+  it('should omit legendFormat in explore url', () => {
+    expect(getExploreUrl(args).then(data => expect(data).not.toMatch(/legendFormat1/g)));
+  });
+});
+
 describe('updateHistory()', () => {
   const datasourceId = 'myDatasource';
   const key = `grafana.explore.history.${datasourceId}`;

public/app/core/utils/explore.ts

@@ -70,7 +70,11 @@ export interface GetExploreUrlArguments {
 export async function getExploreUrl(args: GetExploreUrlArguments): Promise<string | undefined> {
   const { panel, panelTargets, panelDatasource, datasourceSrv, timeSrv } = args;
   let exploreDatasource = panelDatasource;
-  let exploreTargets: DataQuery[] = panelTargets;
+
+  /** In Explore, we don't have legend formatter and we don't want to keep
+   * legend formatting as we can't change it
+   */
+  let exploreTargets: DataQuery[] = panelTargets.map(t => _.omit(t, 'legendFormat'));
   let url: string | undefined;
 
   // Mixed datasources need to choose only one datasource