Avoid allocating new empty arrays, reuse existing empty array

Author: Henr1k80

src/Umbraco.Cms.Api.Delivery/Services/ApiMediaQueryService.cs

@@ -185,7 +185,7 @@ private IPublishedMediaCache GetRequiredPublishedMediaCache()
     }
 
 
-    private Attempt<PagedModel<Guid>, ApiMediaQueryOperationStatus> PagedResult(IEnumerable<IPublishedContent> children, int skip, int take)
+    private static Attempt<PagedModel<Guid>, ApiMediaQueryOperationStatus> PagedResult(IEnumerable<IPublishedContent> children, int skip, int take)
     {
         IPublishedContent[] childrenAsArray = children as IPublishedContent[] ?? children.ToArray();
         var result = new PagedModel<Guid>

src/Umbraco.Core/Models/Membership/User.cs

@@ -53,8 +53,8 @@ public User(GlobalSettings globalSettings)
         _language = globalSettings.DefaultUILanguage;
         _isApproved = true;
         _isLockedOut = false;
-        _startContentIds = new int[] { };
-        _startMediaIds = new int[] { };
+        _startContentIds = [];
+        _startMediaIds = [];
 
         // cannot be null
         _rawPasswordValue = string.Empty;
@@ -101,8 +101,8 @@ public User(GlobalSettings globalSettings, string? name, string email, string us
         _userGroups = new HashSet<IReadOnlyUserGroup>();
         _isApproved = true;
         _isLockedOut = false;
-        _startContentIds = new int[] { };
-        _startMediaIds = new int[] { };
+        _startContentIds = [];
+        _startMediaIds = [];
     }
 
     /// <summary>

src/Umbraco.Infrastructure/Persistence/Repositories/Implement/RelationRepository.cs

@@ -34,10 +34,10 @@ public RelationRepository(IScopeAccessor scopeAccessor, ILogger<RelationReposito
     }
 
     public IEnumerable<IUmbracoEntity> GetPagedParentEntitiesByChildId(int childId, long pageIndex, int pageSize, out long totalRecords, params Guid[] entityTypes)
-        => GetPagedParentEntitiesByChildId(childId, pageIndex, pageSize, out totalRecords, new int[0], entityTypes);
+        => GetPagedParentEntitiesByChildId(childId, pageIndex, pageSize, out totalRecords, [], entityTypes);
 
     public IEnumerable<IUmbracoEntity> GetPagedChildEntitiesByParentId(int parentId, long pageIndex, int pageSize, out long totalRecords, params Guid[] entityTypes)
-        => GetPagedChildEntitiesByParentId(parentId, pageIndex, pageSize, out totalRecords, new int[0], entityTypes);
+        => GetPagedChildEntitiesByParentId(parentId, pageIndex, pageSize, out totalRecords, [], entityTypes);
 
     public Task<PagedModel<IRelation>> GetPagedByChildKeyAsync(Guid childKey, int skip, int take, string? relationTypeAlias)
     {

src/Umbraco.Infrastructure/Persistence/Repositories/Implement/RelationTypeRepository.cs

@@ -17,7 +17,7 @@ namespace Umbraco.Cms.Infrastructure.Persistence.Repositories.Implement;
 /// <summary>
 ///     Represents a repository for doing CRUD operations for <see cref="RelationType" />
 /// </summary>
-internal class RelationTypeRepository : EntityRepositoryBase<int, IRelationType>, IRelationTypeRepository
+internal sealed class RelationTypeRepository : EntityRepositoryBase<int, IRelationType>, IRelationTypeRepository
 {
     public RelationTypeRepository(IScopeAccessor scopeAccessor, AppCaches cache, ILogger<RelationTypeRepository> logger)
         : base(scopeAccessor, cache, logger)
@@ -27,7 +27,7 @@ public RelationTypeRepository(IScopeAccessor scopeAccessor, AppCaches cache, ILo
     protected override IRepositoryCachePolicy<IRelationType, int> CreateCachePolicy() =>
         new FullDataSetRepositoryCachePolicy<IRelationType, int>(GlobalIsolatedCache, ScopeAccessor, GetEntityId, /*expires:*/ true);
 
-    private void CheckNullObjectTypeValues(IRelationType entity)
+    private static void CheckNullObjectTypeValues(IRelationType entity)
     {
         if (entity.ParentObjectType.HasValue && entity.ParentObjectType == Guid.Empty)
         {
@@ -66,12 +66,12 @@ protected override IEnumerable<IRelationType> PerformGetAll(params int[]? ids)
     public IEnumerable<IRelationType> GetMany(params Guid[]? ids)
     {
         // should not happen due to the cache policy
-        if (ids?.Any() ?? false)
+        if (ids is { Length: not 0 })
         {
             throw new NotImplementedException();
         }
 
-        return GetMany(new int[0]);
+        return GetMany(Array.Empty<int>());
     }
 
     protected override IEnumerable<IRelationType> PerformGetByQuery(IQuery<IRelationType> query)

src/Umbraco.Infrastructure/Security/BackOfficeIdentityUser.cs

@@ -63,7 +63,7 @@ public int[] StartContentIds
         get => _startContentIds;
         set
         {
-            value ??= new int[0];
+            value ??= [];
 
             BeingDirty.SetPropertyValueAndDetectChanges(value, ref _startContentIds!, nameof(StartContentIds), _startIdsComparer);
         }

src/Umbraco.Infrastructure/Security/BackOfficeUserStore.cs

@@ -138,8 +138,8 @@ public override Task<IdentityResult> CreateAsync(
         var userEntity = new User(_globalSettings, user.Name, user.Email, user.UserName, emptyPasswordValue)
         {
             Language = user.Culture ?? _globalSettings.DefaultUILanguage,
-            StartContentIds = user.StartContentIds ?? new int[] { },
-            StartMediaIds = user.StartMediaIds ?? new int[] { },
+            StartContentIds = user.StartContentIds ?? [],
+            StartMediaIds = user.StartMediaIds ?? [],
             IsLockedOut = user.IsLockedOut,
             Key = user.Key,
             Kind = user.Kind