✨Add support for [DataMember(IsRequired)]

Add test cases for DataMember (IsRequired and Name).
It seems that NewtonSoft's ResolveContract correctly set the Required, using [DataMember], [JsonProperpty] and [JsonRequired] so we can directly use it instead of the IsRequiredSpecifed extension method.

src/Swashbuckle.AspNetCore.Newtonsoft/SchemaGenerator/JsonPropertyExtensions.cs

@@ -14,19 +14,5 @@ public static bool TryGetMemberInfo(this JsonProperty jsonProperty, out MemberIn
 
             return (memberInfo != null);
         }
-
-        public static bool IsRequiredSpecified(this JsonProperty jsonProperty)
-        {
-            if (!jsonProperty.TryGetMemberInfo(out MemberInfo memberInfo))
-                return false;
-
-            if (memberInfo.GetCustomAttribute<JsonRequiredAttribute>() != null)
-                return true;
-
-            var jsonPropertyAttributeData = memberInfo.GetCustomAttributesData()
-                .FirstOrDefault(attrData => attrData.AttributeType == typeof(JsonPropertyAttribute));
-
-            return (jsonPropertyAttributeData != null) && jsonPropertyAttributeData.NamedArguments.Any(arg => arg.MemberName == "Required");
-        }
     }
 }

src/Swashbuckle.AspNetCore.Newtonsoft/SchemaGenerator/NewtonsoftDataContractResolver.cs

@@ -152,7 +152,7 @@ private List<DataProperty> GetDataPropertiesFor(JsonObjectContract jsonObjectCon
             {
                 if (jsonProperty.Ignored) continue;
 
-                var required = jsonProperty.IsRequiredSpecified()
+                var required = jsonProperty.Required != Required.Default
                     ? jsonProperty.Required
                     : jsonObjectContract.ItemRequired ?? Required.Default;
 

test/Swashbuckle.AspNetCore.Newtonsoft.Test/Fixtures/DataMemberAnnotatedType.cs

@@ -0,0 +1,20 @@
+using System.Runtime.Serialization;
+
+namespace Swashbuckle.AspNetCore.Newtonsoft.Test
+{
+    [DataContract(Name = "CustomNameFromDataContract")]
+    public class DataMemberAnnotatedType
+    {
+        [DataMember(IsRequired = true)]
+        public string StringWithDataMemberRequired { get; set; }
+
+        [DataMember(IsRequired = false)]
+        public string StringWithDataMemberNonRequired { get; set; }
+
+        [DataMember(IsRequired = true, Name = "RequiredWithCustomNameFromDataMember")]
+        public string StringWithDataMemberRequiredWithCustomName { get; set; }
+
+        [DataMember(IsRequired = false, Name = "NonRequiredWithCustomNameFromDataMember")]
+        public string StringWithDataMemberNonRequiredWithCustomName { get; set; }
+    }
+}

test/Swashbuckle.AspNetCore.Newtonsoft.Test/SchemaGenerator/NewtonsoftSchemaGeneratorTests.cs

@@ -828,6 +828,43 @@ public void GenerateSchema_HonorsSerializerAttribute_JsonExtensionData()
             Assert.Null(schema.AdditionalProperties.Type);
         }
 
+        [Fact]
+        public void GenerateSchema_HonorsDataMemberAttribute()
+        {
+            var schemaRepository = new SchemaRepository();
+
+            var referenceSchema = Subject().GenerateSchema(typeof(DataMemberAnnotatedType), schemaRepository);
+
+            var schema = schemaRepository.Schemas[referenceSchema.Reference.Id];
+
+
+            Assert.True(schema.Properties["StringWithDataMemberRequired"].Nullable);
+            Assert.True(schema.Properties["StringWithDataMemberNonRequired"].Nullable);
+            Assert.True(schema.Properties["RequiredWithCustomNameFromDataMember"].Nullable);
+            Assert.True(schema.Properties["NonRequiredWithCustomNameFromDataMember"].Nullable);
+
+            Assert.Equal(
+                new[]
+                {
+
+                    "StringWithDataMemberRequired",
+                    "StringWithDataMemberNonRequired",
+                    "RequiredWithCustomNameFromDataMember",
+                    "NonRequiredWithCustomNameFromDataMember"
+                },
+                schema.Properties.Keys.ToArray()
+            );
+
+            Assert.Equal(
+                new[]
+                {
+                    "RequiredWithCustomNameFromDataMember",
+                    "StringWithDataMemberRequired"
+                },
+                schema.Required.ToArray()
+            );
+        }
+
         [Theory]
         [InlineData(typeof(ProblemDetails))]
         [InlineData(typeof(ValidationProblemDetails))]