SQL Expressions: Filter Dashboard datasource queries from schema fetching (#116129)

* fix(sql expression): sql schema frontend datasources filtering

* add one more test

public/app/features/expressions/components/SqlExpressions/hooks/useSQLSchemas.test.ts

@@ -0,0 +1,26 @@
+import { DataQuery } from '@grafana/schema';
+import { SHARED_DASHBOARD_QUERY } from 'app/plugins/datasource/dashboard/constants';
+
+import { isDashboardDatasource } from './useSQLSchemas';
+
+describe('isDashboardDatasource', () => {
+  it('identifies Dashboard datasource queries in a mixed set', () => {
+    const queries: DataQuery[] = [
+      { refId: 'A', datasource: { uid: 'prometheus-uid', type: 'prometheus' } },
+      { refId: 'B', datasource: { uid: SHARED_DASHBOARD_QUERY, type: 'datasource' } },
+      { refId: 'C', datasource: { uid: 'mysql-uid', type: 'mysql' } },
+    ];
+
+    const backendQueries = queries.filter((q) => !isDashboardDatasource(q));
+
+    expect(backendQueries.map((q) => q.refId)).toEqual(['A', 'C']);
+  });
+
+  it('returns true when query has dashboard datasource uid', () => {
+    const query: DataQuery = {
+      refId: 'A',
+      datasource: { uid: SHARED_DASHBOARD_QUERY, type: 'datasource' },
+    };
+    expect(isDashboardDatasource(query)).toBe(true);
+  });
+});

public/app/features/expressions/components/SqlExpressions/hooks/useSQLSchemas.ts

@@ -4,6 +4,11 @@ import { getAPINamespace } from '@grafana/api-clients';
 import { getDefaultTimeRange, TimeRange } from '@grafana/data';
 import { config, getBackendSrv } from '@grafana/runtime';
 import { DataQuery } from '@grafana/schema';
+import { SHARED_DASHBOARD_QUERY } from 'app/plugins/datasource/dashboard/constants';
+
+export function isDashboardDatasource(query: DataQuery): boolean {
+  return query.datasource?.uid === SHARED_DASHBOARD_QUERY;
+}
 
 export interface SQLSchemaField {
   name: string;
@@ -61,7 +66,10 @@ export function useSQLSchemas({ queries, enabled, timeRange }: UseSQLSchemasOpti
     setError(null);
 
     try {
-      if (currentQueries.length === 0) {
+      // Filter out Dashboard datasource queries - they are frontend-only and can't be processed by backend
+      const backendQueries = currentQueries.filter((q) => !isDashboardDatasource(q));
+
+      if (backendQueries.length === 0) {
         setSchemas({ kind: 'SQLSchemaResponse', apiVersion: 'query.grafana.app/v0alpha1', sqlSchemas: {} });
         setLoading(false);
         return;
@@ -73,7 +81,7 @@ export function useSQLSchemas({ queries, enabled, timeRange }: UseSQLSchemasOpti
       const response = await getBackendSrv().post<SQLSchemasResponse>(
         `/apis/query.grafana.app/v0alpha1/namespaces/${namespace}/sqlschemas/name`,
         {
-          queries: currentQueries,
+          queries: backendQueries,
           from: currentTimeRange.from.toISOString(),
           to: currentTimeRange.to.toISOString(),
         }