diff --git a/Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabPublicHandler.cpp b/Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabPublicHandler.cpp index 475510c52f..d4485f8e99 100644 --- a/Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabPublicHandler.cpp +++ b/Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabPublicHandler.cpp @@ -182,6 +182,22 @@ namespace AzToolsFramework instanceToParentUnder = prefabEditorEntityOwnershipInterface->GetRootPrefabInstance(); parent = instanceToParentUnder->get().GetContainerEntityId(); } + + //Detect whether this instantiation would produce a cyclical dependency + auto relativePath = m_prefabLoaderInterface->GetRelativePathToProject(filePath); + Prefab::TemplateId templateId = m_prefabSystemComponentInterface->GetTemplateIdFromFilePath(relativePath); + + // If the template isn't currently loaded, there's no way for it to be in the hierarchy so we just skip the check. + if (templateId != Prefab::InvalidTemplateId && IsPrefabInInstanceAncestorHierarchy(templateId, instanceToParentUnder->get())) + { + return AZ::Failure( + AZStd::string::format( + "Instantiate Prefab operation aborted - Cyclical dependency detected\n(%s depends on %s).", + relativePath.Native().c_str(), + instanceToParentUnder->get().GetTemplateSourcePath().Native().c_str() + ) + ); + } { // Initialize Undo Batch object @@ -192,7 +208,7 @@ namespace AzToolsFramework instanceToParentUnderDomBeforeCreate, instanceToParentUnder->get()); // Instantiate the Prefab - auto instanceToCreate = prefabEditorEntityOwnershipInterface->InstantiatePrefab(filePath, instanceToParentUnder); + auto instanceToCreate = prefabEditorEntityOwnershipInterface->InstantiatePrefab(relativePath, instanceToParentUnder); if (!instanceToCreate) { @@ -242,6 +258,23 @@ namespace AzToolsFramework return AZ::Success(); } + bool PrefabPublicHandler::IsPrefabInInstanceAncestorHierarchy(TemplateId prefabTemplateId, InstanceOptionalConstReference instance) + { + InstanceOptionalConstReference currentInstance = instance; + + while (currentInstance.has_value()) + { + if (currentInstance->get().GetTemplateId() == prefabTemplateId) + { + return true; + } + + currentInstance = currentInstance->get().GetParentInstance(); + } + + return false; + } + void PrefabPublicHandler::CreateLink( const EntityList& topLevelEntities, Instance& sourceInstance, TemplateId targetTemplateId, UndoSystem::URSequencePoint* undoBatch, AZ::EntityId commonRootEntityId) diff --git a/Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabPublicHandler.h b/Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabPublicHandler.h index 5ade666a40..03b3827328 100644 --- a/Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabPublicHandler.h +++ b/Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabPublicHandler.h @@ -106,6 +106,14 @@ namespace AzToolsFramework const AZStd::vector& entityIds, EntityList& inputEntityList, EntityList& topLevelEntities, AZ::EntityId& commonRootEntityId, InstanceOptionalReference& commonRootEntityOwningInstance); + /* Detects whether an instance of prefabTemplateId is present in the hierarchy of ancestors of instance. + * + * \param prefabTemplateId The template id to test for + * \param instance The instance whose ancestor hierarchy prefabTemplateId will be tested against. + * \return true if an instance of the template of id prefabTemplateId could be found in the ancestor hierarchy of instance, false otherwise. + */ + bool IsPrefabInInstanceAncestorHierarchy(TemplateId prefabTemplateId, InstanceOptionalConstReference instance); + static Instance* GetParentInstance(Instance* instance); static Instance* GetAncestorOfInstanceThatIsChildOfRoot(const Instance* ancestor, Instance* descendant); static void GenerateContainerEntityTransform(const EntityList& topLevelEntities, AZ::Vector3& translation, AZ::Quaternion& rotation); diff --git a/Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabSystemComponent.cpp b/Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabSystemComponent.cpp index 4413586e77..3910e80f75 100644 --- a/Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabSystemComponent.cpp +++ b/Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabSystemComponent.cpp @@ -721,6 +721,8 @@ namespace AzToolsFramework TemplateId PrefabSystemComponent::GetTemplateIdFromFilePath(AZ::IO::PathView filePath) const { + AZ_Assert(!filePath.IsAbsolute(), "Prefab - GetTemplateIdFromFilePath was passed an absolute path. Prefabs use paths relative to the project folder."); + auto found = m_templateFilePathToIdMap.find(filePath); if (found != m_templateFilePathToIdMap.end()) {