Use data type configuration to determine default value for empty toggle and slider property values (#17854)

* Use data type configuration to determine default value for empty toggle property values.

* Added/updated unit tests.

* Fixed failing integration tests.

* Applied similar default value display for the slider property editor and aligned implementation of true/false with this.

* Fixed unit tests.

* Removed "duplicate" JsonPropertyName attributes and added a custom TypeInfoResolver for data type configuration so we can re-use the existing ConfigurationField attributes.

* Minor cleanup

---------

Co-authored-by: nikolajlauridsen <nikolajlauridsen@protonmail.ch>

src/Umbraco.Infrastructure/Serialization/SystemTextConfigurationEditorJsonSerializer.cs

@@ -1,5 +1,7 @@
 using System.Text.Json;
 using System.Text.Json.Serialization;
+using System.Text.Json.Serialization.Metadata;
+using Umbraco.Cms.Core.PropertyEditors;
 using Umbraco.Cms.Core.Serialization;
 
 namespace Umbraco.Cms.Infrastructure.Serialization;
@@ -16,8 +18,9 @@ public sealed class SystemTextConfigurationEditorJsonSerializer : SystemTextJson
         => _jsonSerializerOptions = new JsonSerializerOptions()
         {
             PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
-            // in some cases, configs aren't camel cased in the DB, so we have to resort to case insensitive
-            // property name resolving when creating configuration objects (deserializing DB configs)
+
+            // In some cases, configs aren't camel cased in the DB, so we have to resort to case insensitive
+            // property name resolving when creating configuration objects (deserializing DB configs).
             PropertyNameCaseInsensitive = true,
             NumberHandling = JsonNumberHandling.AllowReadingFromString,
             Converters =
@@ -26,9 +29,42 @@ public sealed class SystemTextConfigurationEditorJsonSerializer : SystemTextJson
                 new JsonObjectConverter(),
                 new JsonUdiConverter(),
                 new JsonUdiRangeConverter(),
-                new JsonBooleanConverter()
-            }
+                new JsonBooleanConverter(),
+            },
+
+            // Properties of data type configuration objects are annotated with [ConfigurationField] attributes
+            // that provide the serialized name. Rather than decorating them as well with [JsonPropertyName] attributes
+            // when they differ from the property name, we'll define a custom type info resolver to use the
+            // existing attribute.
+            TypeInfoResolver = new DefaultJsonTypeInfoResolver()
+                .WithAddedModifier(UseAttributeConfiguredPropertyNames()),
         };
 
     protected override JsonSerializerOptions JsonSerializerOptions => _jsonSerializerOptions;
+
+    /// <summary>
+    /// A custom action used to provide property names when they are overridden by
+    /// <see cref="ConfigurationField"/> attributes.
+    /// </summary>
+    /// <remarks>
+    /// Hat-tip: https://stackoverflow.com/a/78063664
+    /// </remarks>
+    private static Action<JsonTypeInfo> UseAttributeConfiguredPropertyNames() => typeInfo =>
+    {
+        if (typeInfo.Kind is not JsonTypeInfoKind.Object)
+        {
+            return;
+        }
+
+        foreach (JsonPropertyInfo property in typeInfo.Properties)
+        {
+            if (property.AttributeProvider?.GetCustomAttributes(typeof(ConfigurationFieldAttribute), true) is { } attributes)
+            {
+                foreach (ConfigurationFieldAttribute attribute in attributes)
+                {
+                    property.Name = attribute.Key;
+                }
+            }
+        }
+    };
 }