Variables: Fixes problem with data source variable when default ds is selected (#32384) (#32424)

(cherry picked from commit f37c8c10c5)

Co-authored-by: Torkel Ödegaard <torkel@grafana.org>

public/app/features/plugins/datasource_srv.ts

@@ -69,6 +69,9 @@ export class DatasourceSrv implements DataSourceService {
       // The return name or uid needs preservet string containing the variable
       const clone = cloneDeep(dsSettings);
       clone.name = nameOrUid;
+      // A data source being looked up using a variable should not be considered default
+      clone.isDefault = false;
+
       return clone;
     }
 

public/app/features/plugins/specs/datasource_srv.test.ts

@@ -77,6 +77,7 @@ describe('datasource_srv', () => {
       name: 'BBB',
       uid: 'uid-code-BBB',
       meta: { metrics: true },
+      isDefault: true,
     },
     Jaeger: {
       type: 'jaeger-db',
@@ -127,6 +128,11 @@ describe('datasource_srv', () => {
         expect(ds?.uid).toBe('uid-code-BBB');
       });
 
+      it('should not set isDefault when being fetched via variable', () => {
+        const ds = dataSourceSrv.getInstanceSettings('${datasource}');
+        expect(ds?.isDefault).toBe(false);
+      });
+
       it('should work with variable', () => {
         const ds = dataSourceSrv.getInstanceSettings('${datasourceDefault}');
         expect(ds?.name).toBe('${datasourceDefault}');
@@ -182,6 +188,7 @@ describe('datasource_srv', () => {
             "uid": "uid-code-aaa",
           },
           Object {
+            "isDefault": true,
             "meta": Object {
               "metrics": true,
             },