[DataMember(IsRequired = true)] do not mark property as required

[ouvreboite]

Swashbuckle.AspNetCore.SwaggerGen 6.3.0
Swashbuckle.AspNetCore.Newtonsoft 6.3.0

A field annotated with [DataMember(IsRequired = true)] is not marked as required in the generated OpenApi specification.

// class
[DataContract]
public class DataMemberModel
{
    [DataMember(Name = "customId", IsRequired = true)]
    public string Id;
}

// schema
"DataMemberModel": {
    "type": "object",
    "properties": {
        "customId": {  //the id shows that DataMember is indeed used
            "type": "string",
            "nullable": true
        }
    },
    "additionalProperties": false
}

The "required" status is supposed to be set in NewtonsoftDataContractResolver.GetDataPropertiesFor, using JsonPropertyExtensions.IsRequiredSpecified to know if JsonProperty.Required is readable. But JsonPropertyExtensions.IsRequiredSpecified does not actually look at JsonProperty.Required (which is equals to NotNull in our case). It incorrectly return false.

//NewtonsoftDataContractResolver.cs
var required = jsonProperty.IsRequiredSpecified()
      ? jsonProperty.Required
      : jsonObjectContract.ItemRequired ?? Required.Default;

//JsonPropertyExtensions.cs
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");
}

Maybe adding a if(jsonProperty.Required != Required.Default) return true at the start of IsRequiredSpecified could be enough.

[martincostello]

#2644 (comment)

[github-actions]

This issue is stale because it has been open for 60 days with no activity. It will be automatically closed in 14 days if no further updates are made.

[github-actions]

This issue was closed because it has been inactive for 14 days since being marked as stale.