fix(deserializer): skip foreign key if data not in relationship

src/JsonApiDotNetCore/JsonApiDotNetCore.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <VersionPrefix>2.1.9</VersionPrefix>
+    <VersionPrefix>2.1.10</VersionPrefix>
     <TargetFrameworks>netstandard1.6</TargetFrameworks>
     <AssemblyName>JsonApiDotNetCore</AssemblyName>
     <PackageId>JsonApiDotNetCore</PackageId>

src/JsonApiDotNetCore/Serialization/JsonApiDeSerializer.cs

@@ -164,11 +164,6 @@ private object SetHasOneRelationship(object entity,
             ContextEntity contextEntity,
             Dictionary<string, RelationshipData> relationships)
         {
-            var entityProperty = entityProperties.FirstOrDefault(p => p.Name == $"{attr.InternalRelationshipName}Id");
-
-            if (entityProperty == null)
-                throw new JsonApiException(400, $"{contextEntity.EntityType.Name} does not contain an relationsip named {attr.InternalRelationshipName}");
-
             var relationshipName = attr.PublicRelationshipName;
 
             if (relationships.TryGetValue(relationshipName, out RelationshipData relationshipData))
@@ -181,6 +176,12 @@ private object SetHasOneRelationship(object entity,
                 if (data == null) return entity;
 
                 var newValue = data["id"];
+
+                var foreignKey = attr.InternalRelationshipName + "Id";
+                var entityProperty = entityProperties.FirstOrDefault(p => p.Name == foreignKey);
+                if (entityProperty == null)
+                    throw new JsonApiException(400, $"{contextEntity.EntityType.Name} does not contain a foreign key property '{foreignKey}' for has one relationship '{attr.InternalRelationshipName}'");
+
                 var convertedValue = TypeHelper.ConvertType(newValue, entityProperty.PropertyType);
 
                 _jsonApiContext.RelationshipsToUpdate[relationshipAttr] = convertedValue;

test/UnitTests/Serialization/JsonApiDeSerializerTests.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using JsonApiDotNetCore.Builders;
 using JsonApiDotNetCore.Configuration;
 using JsonApiDotNetCore.Internal.Generics;
@@ -196,6 +197,98 @@ public void Immutable_Attrs_Are_Not_Included_In_AttributesToUpdate()
                 Assert.False(attr.Key.IsImmutable);
         }
 
+        [Fact]
+        public void Can_Deserialize_Independent_Side_Of_One_To_One_Relationship()
+        {
+            // arrange
+            var contextGraphBuilder = new ContextGraphBuilder();
+            contextGraphBuilder.AddResource<Independent>("independents");
+            contextGraphBuilder.AddResource<Dependent>("dependents");
+            var contextGraph = contextGraphBuilder.Build();
+
+            var jsonApiContextMock = new Mock<IJsonApiContext>();
+            jsonApiContextMock.SetupAllProperties();
+            jsonApiContextMock.Setup(m => m.ContextGraph).Returns(contextGraph);
+            jsonApiContextMock.Setup(m => m.AttributesToUpdate).Returns(new Dictionary<AttrAttribute, object>());
+
+            var jsonApiOptions = new JsonApiOptions();
+            jsonApiContextMock.Setup(m => m.Options).Returns(jsonApiOptions);
+
+            var genericProcessorFactoryMock = new Mock<IGenericProcessorFactory>();
+
+            var deserializer = new JsonApiDeSerializer(jsonApiContextMock.Object, genericProcessorFactoryMock.Object);
+
+            var property = Guid.NewGuid().ToString();
+            var content = new Document
+            {
+                Data = new DocumentData
+                {
+                    Type = "independents",
+                    Id = "1",
+                    Attributes = new Dictionary<string, object> {
+                        {  "property", property }
+                    }
+                }
+            };
+
+            var contentString = JsonConvert.SerializeObject(content);
+
+            // act
+            var result = deserializer.Deserialize<Independent>(contentString);
+
+            // assert
+            Assert.NotNull(result);
+            Assert.Equal(property, result.Property);
+        }
+
+        [Fact]
+        public void Can_Deserialize_Independent_Side_Of_One_To_One_Relationship_With_Relationship_Body()
+        {
+            // arrange
+            var contextGraphBuilder = new ContextGraphBuilder();
+            contextGraphBuilder.AddResource<Independent>("independents");
+            contextGraphBuilder.AddResource<Dependent>("dependents");
+            var contextGraph = contextGraphBuilder.Build();
+
+            var jsonApiContextMock = new Mock<IJsonApiContext>();
+            jsonApiContextMock.SetupAllProperties();
+            jsonApiContextMock.Setup(m => m.ContextGraph).Returns(contextGraph);
+            jsonApiContextMock.Setup(m => m.AttributesToUpdate).Returns(new Dictionary<AttrAttribute, object>());
+
+            var jsonApiOptions = new JsonApiOptions();
+            jsonApiContextMock.Setup(m => m.Options).Returns(jsonApiOptions);
+
+            var genericProcessorFactoryMock = new Mock<IGenericProcessorFactory>();
+
+            var deserializer = new JsonApiDeSerializer(jsonApiContextMock.Object, genericProcessorFactoryMock.Object);
+
+            var property = Guid.NewGuid().ToString();
+            var content = new Document
+            {
+                Data = new DocumentData
+                {
+                    Type = "independents",
+                    Id = "1",
+                    Attributes = new Dictionary<string, object> {
+                        {  "property", property }
+                    },
+                    // a common case for this is deserialization in unit tests
+                    Relationships = new Dictionary<string, RelationshipData> {
+                        { "dependent", new RelationshipData { } }
+                    }
+                }
+            };
+
+            var contentString = JsonConvert.SerializeObject(content);
+
+            // act
+            var result = deserializer.Deserialize<Independent>(contentString);
+
+            // assert
+            Assert.NotNull(result);
+            Assert.Equal(property, result.Property);
+        }
+
         private class TestResource : Identifiable
         {
             [Attr("complex-member")]
@@ -215,5 +308,17 @@ private class ComplexType
         {
             public string CompoundName { get; set; }
         }
+
+        private class Independent : Identifiable
+        {
+            [Attr("property")] public string Property { get; set; }
+            [HasOne("dependent")] public Dependent Dependent { get; set; }
+        }
+
+        private class Dependent : Identifiable
+        {
+            [HasOne("independent")] public Independent Independent { get; set; }
+            public int IndependentId { get; set; }
+        }
     }
 }