Introduce contracts#SafeInit()

pkg/contracts/contracts.go

@@ -19,3 +19,11 @@ type Checksumer interface {
 type Initer interface {
 	Init() // Init initializes the object.
 }
+
+// SafeInit attempts to initialize the passed argument by calling its Init method,
+// but only if the argument implements the [Initer] interface.
+func SafeInit(v any) {
+	if initer, ok := v.(Initer); ok {
+		initer.Init()
+	}
+}

pkg/icingadb/history/sla.go

@@ -12,11 +12,7 @@ import (
 var slaStateStructify = structify.MakeMapStructifier(
 	reflect.TypeOf((*history.SlaHistoryState)(nil)).Elem(),
 	"json",
-	func(a any) {
-		if initer, ok := a.(contracts.Initer); ok {
-			initer.Init()
-		}
-	})
+	contracts.SafeInit)
 
 func stateHistoryToSlaEntity(entry redis.XMessage) ([]history.UpserterEntity, error) {
 	slaStateInterface, err := slaStateStructify(entry.Values)

pkg/icingadb/history/sync.go

@@ -181,11 +181,7 @@ func writeOneEntityStage(structPtr interface{}) stageFunc {
 	structifier := structify.MakeMapStructifier(
 		reflect.TypeOf(structPtr).Elem(),
 		"json",
-		func(a any) {
-			if initer, ok := a.(contracts.Initer); ok {
-				initer.Init()
-			}
-		})
+		contracts.SafeInit)
 
 	return writeMultiEntityStage(func(entry redis.XMessage) ([]v1.UpserterEntity, error) {
 		ptr, err := structifier(entry.Values)
@@ -324,11 +320,7 @@ func userNotificationStage(ctx context.Context, s Sync, key string, in <-chan re
 	structifier := structify.MakeMapStructifier(
 		reflect.TypeOf((*NotificationHistory)(nil)).Elem(),
 		"structify",
-		func(a any) {
-			if initer, ok := a.(contracts.Initer); ok {
-				initer.Init()
-			}
-		})
+		contracts.SafeInit)
 
 	return writeMultiEntityStage(func(entry redis.XMessage) ([]v1.UpserterEntity, error) {
 		rawNotificationHistory, err := structifier(entry.Values)

pkg/icingadb/runtime_updates.go

@@ -99,11 +99,7 @@ func (r *RuntimeUpdates) Sync(
 			structify.MakeMapStructifier(
 				reflect.TypeOf(s.Entity()).Elem(),
 				"json",
-				func(a any) {
-					if initer, ok := a.(contracts.Initer); ok {
-						initer.Init()
-					}
-				}),
+				contracts.SafeInit),
 		))
 
 		g.Go(func() error {
@@ -166,11 +162,7 @@ func (r *RuntimeUpdates) Sync(
 			structify.MakeMapStructifier(
 				reflect.TypeOf(cv.Entity()).Elem(),
 				"json",
-				func(a any) {
-					if initer, ok := a.(contracts.Initer); ok {
-						initer.Init()
-					}
-				}),
+				contracts.SafeInit),
 		))
 
 		customvars, flatCustomvars, errs := v1.ExpandCustomvars(ctx, upsertEntities)