[v9.3.x] Azure Monitor Logs: Avoid warning when the response is empty (#59231)

Azure Monitor Logs: Avoid warning when the response is empty (#59211)

(cherry picked from commit 9d88e14f01)

Co-authored-by: Andres Martinez Gotor <andres.martinez@grafana.com>

pkg/tsdb/azuremonitor/loganalytics/azure-log-analytics-datasource.go

@@ -315,6 +315,10 @@ type LogAnalyticsMeta struct {
 }
 
 func setAdditionalFrameMeta(frame *data.Frame, query, subscriptionID, workspace string) error {
+	if frame.Meta == nil || frame.Meta.Custom == nil {
+		// empty response
+		return nil
+	}
 	frame.Meta.ExecutedQueryString = query
 	la, ok := frame.Meta.Custom.(*LogAnalyticsMeta)
 	if !ok {

pkg/tsdb/azuremonitor/loganalytics/azure-log-analytics-datasource_test.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/google/go-cmp/cmp"
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
+	"github.com/grafana/grafana-plugin-sdk-go/data"
 	"github.com/stretchr/testify/require"
 
 	"github.com/grafana/grafana/pkg/infra/log"
@@ -242,3 +243,11 @@ func Test_executeQueryErrorWithDifferentLogAnalyticsCreds(t *testing.T) {
 		t.Error("expecting the error to inform of bad credentials")
 	}
 }
+
+func Test_setAdditionalFrameMeta(t *testing.T) {
+	t.Run("it should not error with an empty response", func(t *testing.T) {
+		frame := data.NewFrame("test")
+		err := setAdditionalFrameMeta(frame, "", "", "")
+		require.NoError(t, err)
+	})
+}