fix: Gracefully handle missing event labels (#446)

pkg/lib/v0_2_0/keptn.go

@@ -206,6 +206,9 @@ func ensureContextAttributesAreSet(srcEvent, newEvent keptn.EventProperties) kep
 	newEvent.SetStage(srcEvent.GetStage())
 	newEvent.SetService(srcEvent.GetService())
 	labels := srcEvent.GetLabels()
+	if labels == nil {
+		labels = make(map[string]string)
+	}
 
 	// make sure labels from triggered event are included. Existing labels cannot be changed, but new ones can be added
 	for key, value := range newEvent.GetLabels() {

pkg/lib/v0_2_0/keptn_test.go

@@ -72,6 +72,7 @@ func Test_ensureContextAttributesAreSet(t *testing.T) {
 				},
 			},
 		},
+
 		{
 			name: "merge labels - do not overwrite existing ones",
 			args: args{
@@ -103,6 +104,82 @@ func Test_ensureContextAttributesAreSet(t *testing.T) {
 				},
 			},
 		},
+
+		{
+			name: "gracefully handle missing src labels",
+			args: args{
+				srcEvent: &EventData{
+					Project: "my-project",
+					Stage:   "my-stage",
+					Service: "my-service",
+				},
+				newEvent: &EventData{
+					Project: "my-project",
+					Stage:   "my-stage",
+					Service: "my-service",
+					Labels: map[string]string{
+						"bar": "foo",
+					},
+				},
+			},
+			want: &EventData{
+				Project: "my-project",
+				Stage:   "my-stage",
+				Service: "my-service",
+				Labels: map[string]string{
+					"bar": "foo",
+				},
+			},
+		},
+
+		{
+			name: "gracefully handle missing dest labels",
+			args: args{
+				srcEvent: &EventData{
+					Project: "my-project",
+					Stage:   "my-stage",
+					Service: "my-service",
+					Labels: map[string]string{
+						"bar": "foo",
+					},
+				},
+				newEvent: &EventData{
+					Project: "my-project",
+					Stage:   "my-stage",
+					Service: "my-service",
+				},
+			},
+			want: &EventData{
+				Project: "my-project",
+				Stage:   "my-stage",
+				Service: "my-service",
+				Labels: map[string]string{
+					"bar": "foo",
+				},
+			},
+		},
+
+		{
+			name: "gracefully handle missing labels",
+			args: args{
+				srcEvent: &EventData{
+					Project: "my-project",
+					Stage:   "my-stage",
+					Service: "my-service",
+				},
+				newEvent: &EventData{
+					Project: "my-project",
+					Stage:   "my-stage",
+					Service: "my-service",
+				},
+			},
+			want: &EventData{
+				Project: "my-project",
+				Stage:   "my-stage",
+				Service: "my-service",
+				Labels:  map[string]string{},
+			},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {