Loki: strip out invalid options for logs/metrics queries (#79409)

* fix bug in split query where metric queries with maxLines of 0 would not execute

public/app/plugins/datasource/loki/querySplitting.test.ts

@@ -42,6 +42,28 @@ describe('runSplitQuery()', () => {
     });
   });
 
+  test('Metric queries with maxLines of 0 will execute', async () => {
+    const request = getQueryOptions<LokiQuery>({
+      targets: [{ expr: 'count_over_time({a="b"}[1m])', refId: 'A', maxLines: 0 }],
+      range,
+    });
+    await expect(runSplitQuery(datasource, request)).toEmitValuesWith(() => {
+      // 3 days, 3 chunks, 3 requests.
+      expect(datasource.runQuery).toHaveBeenCalledTimes(3);
+    });
+  });
+
+  test('Log queries with maxLines of 0 will NOT execute', async () => {
+    const request = getQueryOptions<LokiQuery>({
+      targets: [{ expr: '{a="b"}', refId: 'A', maxLines: 0 }],
+      range,
+    });
+    await expect(runSplitQuery(datasource, request)).toEmitValuesWith(() => {
+      // Will not request a log query with maxLines of 0
+      expect(datasource.runQuery).toHaveBeenCalledTimes(0);
+    });
+  });
+
   test('Returns a DataQueryResponse with the expected attributes', async () => {
     await expect(runSplitQuery(datasource, request)).toEmitValuesWith((response) => {
       expect(response[0].data).toBeDefined();

public/app/plugins/datasource/loki/querySplitting.ts

@@ -246,8 +246,12 @@ export function runSplitQuery(datasource: LokiDatasource, request: DataQueryRequ
     );
 
     for (const stepMs in stepMsPartition) {
+      const targets = stepMsPartition[stepMs].map((q) => {
+        const { maxLines, ...query } = q;
+        return query;
+      });
       requests.push({
-        request: { ...request, targets: stepMsPartition[stepMs] },
+        request: { ...request, targets },
         partition: partitionTimeRange(false, request.range, Number(stepMs), Number(chunkRangeMs)),
       });
     }