Explore: Fix running queries without a datasource property set (#40805) (#40881)

* Explore: Fix running queries without a datasource property set

* fix test

* adjust test

(cherry picked from commit 2ee54b7ffe)

Co-authored-by: Giordano Ricci <me@giordanoricci.com>

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

@@ -243,7 +243,7 @@ describe('hasNonEmptyQuery', () => {
   });
 
   test('should return false if query is empty', () => {
-    expect(hasNonEmptyQuery([{ refId: '1', key: '2', context: 'panel' }])).toBeFalsy();
+    expect(hasNonEmptyQuery([{ refId: '1', key: '2', context: 'panel', datasource: 'some-ds' }])).toBeFalsy();
   });
 
   test('should return false if no queries exist', () => {

public/app/core/utils/explore.ts

@@ -282,9 +282,12 @@ export function ensureQueries(queries?: DataQuery[]): DataQuery[] {
 }
 
 /**
- * A target is non-empty when it has keys (with non-empty values) other than refId, key and context.
+ * A target is non-empty when it has keys (with non-empty values) other than refId, key, context and datasource.
+ * FIXME: While this is reasonable for practical use cases, a query without any propery might still be "non-empty"
+ * in its own scope, for instance when there's no user input needed. This might be the case for an hypothetic datasource in
+ * which query options are only set in its config and the query object itself, as generated from its query editor it's always "empty"
  */
-const validKeys = ['refId', 'key', 'context'];
+const validKeys = ['refId', 'key', 'context', 'datasource'];
 export function hasNonEmptyQuery<TQuery extends DataQuery>(queries: TQuery[]): boolean {
   return (
     queries &&

public/app/features/explore/state/query.ts

@@ -285,7 +285,6 @@ export const runQueries = (
     const exploreItemState = getState().explore[exploreId]!;
     const {
       datasourceInstance,
-      queries,
       containerWidth,
       isLive: live,
       range,
@@ -299,6 +298,11 @@ export const runQueries = (
     } = exploreItemState;
     let newQuerySub;
 
+    const queries = exploreItemState.queries.map((query) => ({
+      ...query,
+      datasource: query.datasource || datasourceInstance?.name,
+    }));
+
     const cachedValue = getResultsFromCache(cache, absoluteRange);
 
     // If we have results saved in cache, we are going to use those results instead of running queries