Relations: Exclude the relate parent on delete relation type from checks for related documents and media on delete, when disable delete with references is enabled (closes #20803) (#20811)

* Exclude the relate parent on delete relation type from checks for related documents and media on delete, when disable delete with references is enabled.

* Apply suggestions from code review

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Applied suggestions from code review.

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

src/Umbraco.Core/Persistence/Querying/IQuery.cs

@@ -30,6 +30,14 @@ public interface IQuery<T>
     /// <returns>This instance so calls to this method are chainable</returns>
     IQuery<T> WhereIn(Expression<Func<T, object>> fieldSelector, IEnumerable? values);
 
+    /// <summary>
+    ///     Adds a where-not-in clause to the query
+    /// </summary>
+    /// <param name="fieldSelector"></param>
+    /// <param name="values"></param>
+    /// <returns>This instance so calls to this method are chainable</returns>
+    IQuery<T> WhereNotIn(Expression<Func<T, object>> fieldSelector, IEnumerable? values) => throw new NotImplementedException(); // TODO (V18): Remove default implementation.
+
     /// <summary>
     ///     Adds a set of OR-ed where clauses to the query.
     /// </summary>

src/Umbraco.Core/Services/ContentEditingService.cs

@@ -62,6 +62,9 @@ internal sealed class ContentEditingService
         _languageService = languageService;
     }
 
+    /// <inheritdoc/>
+    protected override string? RelateParentOnDeleteAlias => Constants.Conventions.RelationTypes.RelateParentDocumentOnDeleteAlias;
+
     public Task<IContent?> GetAsync(Guid key)
     {
         IContent? content = ContentService.GetById(key);

src/Umbraco.Core/Services/ContentEditingServiceBase.cs

@@ -75,6 +75,11 @@ internal abstract class ContentEditingServiceBase<TContent, TContentType, TConte
 
     protected TContentTypeService ContentTypeService { get; }
 
+    /// <summary>
+    /// Gets the alias used to relate the parent entity when handling content (document or media) delete operations.
+    /// </summary>
+    protected virtual string? RelateParentOnDeleteAlias => null;
+
     protected async Task<Attempt<TContentCreateResult, ContentEditingOperationStatus>> MapCreate<TContentCreateResult>(ContentCreationModelBase contentCreationModelBase)
         where TContentCreateResult : ContentCreateResultBase<TContent>, new()
     {
@@ -202,9 +207,27 @@ internal abstract class ContentEditingServiceBase<TContent, TContentType, TConte
             return Attempt.FailWithStatus<TContent?, ContentEditingOperationStatus>(status, content);
         }
 
-        if (disabledWhenReferenced && _relationService.IsRelated(content.Id, RelationDirectionFilter.Child))
+        if (disabledWhenReferenced)
         {
-            return Attempt.FailWithStatus<TContent?, ContentEditingOperationStatus>(referenceFailStatus, content);
+            // When checking if an item is related, we may need to exclude the "relate parent on delete" relation type, as this prevents
+            // deleting from the recycle bin.
+            int[]? excludeRelationTypeIds = null;
+            if (string.IsNullOrWhiteSpace(RelateParentOnDeleteAlias) is false)
+            {
+                IRelationType? relateParentOnDeleteRelationType = _relationService.GetRelationTypeByAlias(RelateParentOnDeleteAlias);
+                if (relateParentOnDeleteRelationType is not null)
+                {
+                    excludeRelationTypeIds = [relateParentOnDeleteRelationType.Id];
+                }
+            }
+
+            if (_relationService.IsRelated(
+                content.Id,
+                RelationDirectionFilter.Child,
+                excludeRelationTypeIds: excludeRelationTypeIds))
+            {
+                return Attempt.FailWithStatus<TContent?, ContentEditingOperationStatus>(referenceFailStatus, content);
+            }
         }
 
         var userId = await GetUserIdAsync(userKey);

src/Umbraco.Core/Services/IRelationService.cs

@@ -297,9 +297,24 @@ public interface IRelationService : IService
     /// </summary>
     /// <param name="id">Id of an object to check relations for</param>
     /// <param name="directionFilter">Indicates whether to check for relations as parent, child or in either direction.</param>
-    /// <returns>Returns <c>True</c> if any relations exists with the given Id, otherwise <c>False</c></returns>
+    /// <returns>Returns <c>True</c> if any relations exists with the given Id, otherwise <c>False</c>.</returns>
+    [Obsolete("Please use the overload taking all parameters. Scheduled for removal in Umbraco 18.")]
     bool IsRelated(int id, RelationDirectionFilter directionFilter);
 
+    /// <summary>
+    ///     Checks whether any relations exists for the passed in Id and direction.
+    /// </summary>
+    /// <param name="id">Id of an object to check relations for</param>
+    /// <param name="directionFilter">Indicates whether to check for relations as parent, child or in either direction.</param>
+    /// <param name="includeRelationTypeIds">A collection of relation type Ids to include consideration in the relation checks.</param>
+    /// <param name="excludeRelationTypeIds">A collection of relation type Ids to exclude from consideration in the relation checks.</param>
+    /// <remarks>If no relation type Ids are provided in includeRelationTypeIds or excludeRelationTypeIds, all relation type Ids are considered.</remarks>
+    /// <returns>Returns <c>True</c> if any relations exists with the given Id, otherwise <c>False</c>.</returns>
+    bool IsRelated(int id, RelationDirectionFilter directionFilter, int[]? includeRelationTypeIds = null, int[]? excludeRelationTypeIds = null)
+#pragma warning disable CS0618 // Type or member is obsolete
+        => IsRelated(id, directionFilter);
+#pragma warning restore CS0618 // Type or member is obsolete
+
     /// <summary>
     ///     Checks whether two items are related
     /// </summary>

src/Umbraco.Core/Services/MediaEditingService.cs

@@ -43,6 +43,9 @@ internal sealed class MediaEditingService
             contentTypeFilters)
         => _logger = logger;
 
+    /// <inheritdoc/>
+    protected override string? RelateParentOnDeleteAlias => Constants.Conventions.RelationTypes.RelateParentMediaFolderOnDeleteAlias;
+
     public Task<IMedia?> GetAsync(Guid key)
     {
         IMedia? media = ContentService.GetById(key);

src/Umbraco.Core/Services/RelationService.cs

@@ -485,11 +485,14 @@ public class RelationService : RepositoryService, IRelationService
         return _relationRepository.Get(query).Any();
     }
 
-    /// <inheritdoc />
-    public bool IsRelated(int id) => IsRelated(id, RelationDirectionFilter.Any);
+    [Obsolete("No longer used in Umbraco, please the overload taking all parameters. Scheduled for removal in Umbraco 19.")]
+    public bool IsRelated(int id) => IsRelated(id, RelationDirectionFilter.Any, null, null);
+
+    [Obsolete("Please the overload taking all parameters. Scheduled for removal in Umbraco 18.")]
+    public bool IsRelated(int id, RelationDirectionFilter directionFilter) => IsRelated(id, directionFilter, null, null);
 
     /// <inheritdoc />
-    public bool IsRelated(int id, RelationDirectionFilter directionFilter)
+    public bool IsRelated(int id, RelationDirectionFilter directionFilter, int[]? includeRelationTypeIds = null, int[]? excludeRelationTypeIds = null)
     {
         using ICoreScope scope = ScopeProvider.CreateCoreScope(autoComplete: true);
         IQuery<IRelation> query = Query<IRelation>();
@@ -502,6 +505,16 @@ public class RelationService : RepositoryService, IRelationService
             _ => throw new ArgumentOutOfRangeException(nameof(directionFilter)),
         };
 
+        if (includeRelationTypeIds is not null && includeRelationTypeIds.Length > 0)
+        {
+            query = query.WhereIn(x => x.RelationTypeId, includeRelationTypeIds);
+        }
+
+        if (excludeRelationTypeIds is not null && excludeRelationTypeIds.Length > 0)
+        {
+            query = query.WhereNotIn(x => x.RelationTypeId, excludeRelationTypeIds);
+        }
+
         return _relationRepository.Get(query).Any();
     }