Check for invalid legend attributes

decoder/dashboard_test.go

@@ -205,6 +205,24 @@ rows:
 	require.Equal(t, ErrNoAlertThresholdDefined, err)
 }
 
+func TestUnmarshalYAMLWithInvalidLegendGraph(t *testing.T) {
+	payload := `
+rows:
+  - name: Test row
+    panels:
+      - graph:
+          title: Heap allocations
+          legend: [invalid_attribute]
+          targets:
+            - prometheus: { query: "go_memstats_heap_alloc_bytes" }
+`
+
+	_, err := UnmarshalYAML(bytes.NewBufferString(payload))
+
+	require.Error(t, err)
+	require.Equal(t, ErrInvalidLegendAttribute, err)
+}
+
 func TestUnmarshalYAMLWithInvalidAlertValueFunctionGraph(t *testing.T) {
 	payload := `
 rows:

decoder/graph.go

@@ -11,6 +11,7 @@ import (
 
 var ErrNoAlertThresholdDefined = fmt.Errorf("no threshold defined")
 var ErrInvalidAlertValueFunc = fmt.Errorf("invalid alert value function")
+var ErrInvalidLegendAttribute = fmt.Errorf("invalid legend attribute")
 
 type DashboardGraph struct {
 	Title      string
@@ -100,6 +101,8 @@ func (graphPanel *DashboardGraph) legend() ([]graph.LegendOption, error) {
 			opt = graph.NoNullSeries
 		case "no_zero_series":
 			opt = graph.NoZeroSeries
+		default:
+			return nil, ErrInvalidLegendAttribute
 		}
 
 		opts = append(opts, opt)