Dashboard: Migration [Panel Edit] Missing Query Editor when datasource is not found (#86789)

* Return default datasource if datasource is not found

* Set query runner datasource state to default, else refreshing will not work

public/app/features/dashboard-scene/panel-edit/VizPanelManager.test.tsx

@@ -1,7 +1,7 @@
 import { map, of } from 'rxjs';
 
 import { DataQueryRequest, DataSourceApi, DataSourceInstanceSettings, LoadingState, PanelData } from '@grafana/data';
-import { locationService } from '@grafana/runtime';
+import { config, locationService } from '@grafana/runtime';
 import { SceneQueryRunner, VizPanel } from '@grafana/scenes';
 import { DataQuery, DataSourceJsonData, DataSourceRef } from '@grafana/schema';
 import { getDashboardSrv } from 'app/features/dashboard/services/DashboardSrv';
@@ -75,6 +75,18 @@ const ds3Mock: DataSourceApi = {
   },
 } as DataSourceApi<DataQuery, DataSourceJsonData, {}>;
 
+const defaultDsMock: DataSourceApi = {
+  meta: {
+    id: 'grafana-testdata-datasource',
+  },
+  name: 'grafana-testdata-datasource',
+  type: 'grafana-testdata-datasource',
+  uid: 'gdev-testdata',
+  getRef: () => {
+    return { type: 'grafana-testdata-datasource', uid: 'gdev-testdata' };
+  },
+} as DataSourceApi<DataQuery, DataSourceJsonData, {}>;
+
 const instance1SettingsMock = {
   id: 1,
   uid: 'gdev-testdata',
@@ -124,6 +136,7 @@ jest.mock('@grafana/runtime', () => ({
   getDataSourceSrv: () => ({
     get: async (ref: DataSourceRef) => {
       // Mocking the build in Grafana data source to avoid annotations data layer errors.
+
       if (ref.uid === '-- Grafana --') {
         return grafanaDs;
       }
@@ -140,7 +153,8 @@ jest.mock('@grafana/runtime', () => ({
         return ds3Mock;
       }
 
-      return null;
+      // if datasource is not found, return default datasource
+      return defaultDsMock;
     },
     getInstanceSettings: (ref: DataSourceRef) => {
       if (ref.uid === 'gdev-testdata') {
@@ -151,12 +165,17 @@ jest.mock('@grafana/runtime', () => ({
         return instance2SettingsMock;
       }
 
-      return null;
+      // if datasource is not found, return default instance settings
+      return instance1SettingsMock;
     },
   }),
   locationService: {
     partial: jest.fn(),
   },
+  config: {
+    ...jest.requireActual('@grafana/runtime').config,
+    defaultDatasource: 'gdev-testdata',
+  },
 }));
 
 describe('VizPanelManager', () => {
@@ -350,6 +369,21 @@ describe('VizPanelManager', () => {
           datasourceUid: 'gdev-testdata',
         });
       });
+
+      it('should load default datasource if the datasource passed is not found', async () => {
+        const { vizPanelManager } = setupTest('panel-6');
+        vizPanelManager.activate();
+        await Promise.resolve();
+
+        expect(vizPanelManager.queryRunner.state.datasource).toEqual({
+          uid: 'abc',
+          type: 'datasource',
+        });
+
+        expect(config.defaultDatasource).toBe('gdev-testdata');
+        expect(vizPanelManager.state.datasource).toEqual(defaultDsMock);
+        expect(vizPanelManager.state.dsSettings).toEqual(instance1SettingsMock);
+      });
     });
 
     describe('data source change', () => {

public/app/features/dashboard-scene/panel-edit/VizPanelManager.tsx

@@ -154,6 +154,24 @@ export class VizPanelManager extends SceneObjectBase<VizPanelManagerState> {
         );
       }
     } catch (err) {
+      //set default datasource if we fail to load the datasource
+      const datasource = await getDataSourceSrv().get(config.defaultDatasource);
+      const dsSettings = getDataSourceSrv().getInstanceSettings(config.defaultDatasource);
+
+      if (datasource && dsSettings) {
+        this.setState({
+          datasource,
+          dsSettings,
+        });
+
+        this.queryRunner.setState({
+          datasource: {
+            uid: dsSettings.uid,
+            type: dsSettings.type,
+          },
+        });
+      }
+
       console.error(err);
     }
   }

public/app/features/dashboard-scene/panel-edit/testfiles/testDashboard.ts

@@ -410,6 +410,94 @@ export const panelWithNoDataSource = {
   title: 'Panel with no data source',
   type: 'timeseries',
 };
+
+export const panelWithDataSourceNotFound = {
+  datasource: {
+    type: 'datasource',
+    uid: 'abc',
+  },
+  fieldConfig: {
+    defaults: {
+      color: {
+        mode: 'palette-classic',
+      },
+      custom: {
+        axisBorderShow: false,
+        axisCenteredZero: false,
+        axisColorMode: 'text',
+        axisLabel: '',
+        axisPlacement: 'auto',
+        barAlignment: 0,
+        drawStyle: 'line',
+        fillOpacity: 0,
+        gradientMode: 'none',
+        hideFrom: {
+          legend: false,
+          tooltip: false,
+          viz: false,
+        },
+        insertNulls: false,
+        lineInterpolation: 'linear',
+        lineWidth: 1,
+        pointSize: 5,
+        scaleDistribution: {
+          type: 'linear',
+        },
+        showPoints: 'auto',
+        spanNulls: false,
+        stacking: {
+          group: 'A',
+          mode: 'none',
+        },
+        thresholdsStyle: {
+          mode: 'off',
+        },
+      },
+      mappings: [],
+      thresholds: {
+        mode: 'absolute',
+        steps: [
+          {
+            color: 'green',
+            value: null,
+          },
+          {
+            color: 'red',
+            value: 80,
+          },
+        ],
+      },
+    },
+    overrides: [],
+  },
+  gridPos: {
+    h: 8,
+    w: 12,
+    x: 0,
+    y: 0,
+  },
+  id: 6,
+  options: {
+    legend: {
+      calcs: [],
+      displayMode: 'list',
+      placement: 'bottom',
+      showLegend: true,
+    },
+    tooltip: {
+      mode: 'single',
+      sort: 'none',
+    },
+  },
+  targets: [
+    {
+      refId: 'A',
+    },
+  ],
+  title: 'Panel with no data source',
+  type: 'timeseries',
+};
+
 export const testDashboard = {
   annotations: {
     list: [
@@ -439,6 +527,7 @@ export const testDashboard = {
     panelWithDashboardQuery,
     panelWithDashboardQueryAndTransformations,
     panelWithNoDataSource,
+    panelWithDataSourceNotFound,
   ],
   refresh: '',
   schemaVersion: 39,