Switched to STJ in attribute change tracking. This used to take options into account, which is unneeded because we only care about whether there's a diff, not so much what that diff looks like. And we don't expect self-references here (it would have crashed in the past, and will now too).

Author: Bart Koelman

src/JsonApiDotNetCore/Resources/ResourceChangeTracker.cs

@@ -1,8 +1,8 @@
 using System.Collections.Generic;
+using System.Text.Json;
 using JetBrains.Annotations;
 using JsonApiDotNetCore.Configuration;
 using JsonApiDotNetCore.Resources.Annotations;
-using Newtonsoft.Json;
 
 namespace JsonApiDotNetCore.Resources
 {
@@ -11,21 +11,18 @@ namespace JsonApiDotNetCore.Resources
     public sealed class ResourceChangeTracker<TResource> : IResourceChangeTracker<TResource>
         where TResource : class, IIdentifiable
     {
-        private readonly IJsonApiOptions _options;
         private readonly IResourceGraph _resourceGraph;
         private readonly ITargetedFields _targetedFields;
 
         private IDictionary<string, string> _initiallyStoredAttributeValues;
         private IDictionary<string, string> _requestAttributeValues;
         private IDictionary<string, string> _finallyStoredAttributeValues;
 
-        public ResourceChangeTracker(IJsonApiOptions options, IResourceGraph resourceGraph, ITargetedFields targetedFields)
+        public ResourceChangeTracker(IResourceGraph resourceGraph, ITargetedFields targetedFields)
         {
-            ArgumentGuard.NotNull(options, nameof(options));
             ArgumentGuard.NotNull(resourceGraph, nameof(resourceGraph));
             ArgumentGuard.NotNull(targetedFields, nameof(targetedFields));
 
-            _options = options;
             _resourceGraph = resourceGraph;
             _targetedFields = targetedFields;
         }
@@ -63,7 +60,7 @@ private IDictionary<string, string> CreateAttributeDictionary(TResource resource
             foreach (AttrAttribute attribute in attributes)
             {
                 object value = attribute.GetValue(resource);
-                string json = JsonConvert.SerializeObject(value, _options.SerializerSettings);
+                string json = JsonSerializer.Serialize(value);
                 result.Add(attribute.PublicName, json);
             }