v10: Fix Block List settings exception and optimize PVCs (#12342)

* Don't use MapModelType to get model type

* Optimize block list item activation (cache constructors)

* Fix exceptions in NestedContentSingleValueConverter (zero content types or multiple stored items)

* Add IPublishedModelFactory.GetModelType method to remove work-around

src/Umbraco.Core/Models/PublishedContent/PublishedModelFactory.cs

@@ -1,6 +1,4 @@
-using System;
 using System.Collections;
-using System.Collections.Generic;
 using System.Reflection;
 
 namespace Umbraco.Cms.Core.Models.PublishedContent
@@ -59,20 +57,27 @@ namespace Umbraco.Cms.Core.Models.PublishedContent
                     if (parms.Length == 2 && typeof(IPublishedElement).IsAssignableFrom(parms[0].ParameterType) && typeof(IPublishedValueFallback).IsAssignableFrom(parms[1].ParameterType))
                     {
                         if (constructor != null)
+                        {
                             throw new InvalidOperationException($"Type {type.FullName} has more than one public constructor with one argument of type, or implementing, IPublishedElement.");
+                        }
+
                         constructor = ctor;
                         parameterType = parms[0].ParameterType;
                     }
                 }
 
                 if (constructor == null)
+                {
                     throw new InvalidOperationException($"Type {type.FullName} is missing a public constructor with one argument of type, or implementing, IPublishedElement.");
+                }
 
                 var attribute = type.GetCustomAttribute<PublishedModelAttribute>(false);
                 var typeName = attribute == null ? type.Name : attribute.ContentTypeAlias;
 
                 if (modelInfos.TryGetValue(typeName, out var modelInfo))
+                {
                     throw new InvalidOperationException($"Both types '{type.AssemblyQualifiedName}' and '{modelInfo.ModelType?.AssemblyQualifiedName}' want to be a model type for content type with alias \"{typeName}\".");
+                }
 
                 // have to use an unsafe ctor because we don't know the types, really
                 var modelCtor = ReflectionUtilities.EmitConstructorUnsafe<Func<object, IPublishedValueFallback, object>>(constructor);
@@ -89,15 +94,16 @@ namespace Umbraco.Cms.Core.Models.PublishedContent
         public IPublishedElement CreateModel(IPublishedElement element)
         {
             // fail fast
-            if (_modelInfos == null)
-                return element;
-
-            if (element.ContentType.Alias is null || !_modelInfos.TryGetValue(element.ContentType.Alias, out var modelInfo))
+            if (_modelInfos is null || element.ContentType.Alias is null || !_modelInfos.TryGetValue(element.ContentType.Alias, out var modelInfo))
+            {
                 return element;
+            }
 
             // ReSharper disable once UseMethodIsInstanceOfType
             if (modelInfo.ParameterType?.IsAssignableFrom(element.GetType()) == false)
+            {
                 throw new InvalidOperationException($"Model {modelInfo.ModelType} expects argument of type {modelInfo.ParameterType.FullName}, but got {element.GetType().FullName}.");
+            }
 
             // can cast, because we checked when creating the ctor
             return (IPublishedElement)modelInfo.Ctor!(element, _publishedValueFallback);
@@ -107,21 +113,42 @@ namespace Umbraco.Cms.Core.Models.PublishedContent
         public IList? CreateModelList(string? alias)
         {
             // fail fast
-            if (_modelInfos == null)
-                return new List<IPublishedElement>();
-
-            if (alias is null || !_modelInfos.TryGetValue(alias, out var modelInfo) || modelInfo.ModelType is null)
+            if (_modelInfos is null || alias is null || !_modelInfos.TryGetValue(alias, out var modelInfo) || modelInfo.ModelType is null)
+            {
                 return new List<IPublishedElement>();
+            }
 
             var ctor = modelInfo.ListCtor;
-            if (ctor != null) return ctor();
+            if (ctor != null)
+            {
+                return ctor();
+            }
 
             var listType = typeof(List<>).MakeGenericType(modelInfo.ModelType);
             ctor = modelInfo.ListCtor = ReflectionUtilities.EmitConstructor<Func<IList>>(declaring: listType);
-            if(ctor is not null) return ctor();
+            if (ctor is not null)
+            {
+                return ctor();
+            }
+
             return null;
         }
 
+        /// <inheritdoc />
+        public Type GetModelType(string? alias)
+        {
+            // fail fast
+            if (_modelInfos is null ||
+                alias is null ||
+                !_modelInfos.TryGetValue(alias, out var modelInfo) ||
+                modelInfo.ModelType is null)
+            {
+                return typeof(IPublishedElement);
+            }
+
+            return modelInfo.ModelType;
+        }
+
         /// <inheritdoc />
         public Type MapModelType(Type type)
             => ModelType.Map(type, _modelTypeMap);