Fix panics in Kubernetes plugin (#1157)

* Fix panics in Kubernetes plugin
* Fix test assertion

internal/source/kubernetes/registration.go

@@ -141,7 +141,7 @@ func (r registration) matchEvent(routes []route, event event.Event) (bool, error
 	errs := multierror.New()
 	for _, rt := range routes {
 		// event reason
-		if rt.event.Reason.AreConstraintsDefined() {
+		if rt.event != nil && rt.event.Reason.AreConstraintsDefined() {
 			match, err := rt.event.Reason.IsAllowed(event.Reason)
 			if err != nil {
 				return false, err
@@ -153,7 +153,7 @@ func (r registration) matchEvent(routes []route, event event.Event) (bool, error
 		}
 
 		// event message
-		if rt.event.Message.AreConstraintsDefined() {
+		if rt.event != nil && rt.event.Message.AreConstraintsDefined() {
 			var anyMsgMatches bool
 
 			eventMsgs := event.Messages
@@ -191,7 +191,7 @@ func (r registration) matchEvent(routes []route, event event.Event) (bool, error
 		}
 
 		// namespace
-		if rt.namespaces.AreConstraintsDefined() {
+		if rt.namespaces != nil && rt.namespaces.AreConstraintsDefined() {
 			match, err := rt.namespaces.IsAllowed(event.Namespace)
 			if err != nil {
 				return false, err
@@ -291,6 +291,15 @@ func (r registration) qualifyEventForUpdate(
 		r.log.Error("Failed to typecast new object to Unstructured.")
 	}
 
+	if oldUnstruct == nil {
+		r.log.Debugf("oldUnstruct is nil, creating an empty one")
+		oldUnstruct = &unstructured.Unstructured{}
+	}
+	if newUnstruct == nil {
+		r.log.Debugf("newUnstruct is nil, creating an empty one")
+		newUnstruct = &unstructured.Unstructured{}
+	}
+
 	var result bool
 
 	for _, route := range routes {
@@ -300,6 +309,12 @@ func (r registration) qualifyEventForUpdate(
 			continue
 		}
 
+		if route.updateSetting == nil {
+			// in theory this should never happen, as we check if it is not nil in `route.hasActionableUpdateSetting()`, but just in case
+			r.log.Debugf("Nil updateSetting but hasActionableUpdateSetting returned true for route: %v. This looks like a bug...", route)
+			continue
+		}
+
 		r.log.WithFields(logrus.Fields{"old": oldUnstruct.Object, "new": newUnstruct.Object}).Debug("Getting diff for objects...")
 		diff, err := k8sutil.Diff(oldUnstruct.Object, newUnstruct.Object, *route.updateSetting)
 		if err != nil {

internal/source/kubernetes/router.go

@@ -29,7 +29,7 @@ type route struct {
 }
 
 func (r route) hasActionableUpdateSetting() bool {
-	return len(r.updateSetting.Fields) > 0
+	return r.updateSetting != nil && len(r.updateSetting.Fields) > 0
 }
 
 type entry struct {

test/e2e/migration_test.go

@@ -264,7 +264,7 @@ func assertAliases(t *testing.T, actual []*gqlModel.Alias) {
 		},
 	}
 
-	assert.Len(t, actual, 2)
+	assert.Len(t, actual, 4)
 
 	// trim ID and deployments
 	for i := range actual {