System.Text.Json.JsonSerializer.Serialize, when JsonIgnoreAttribute and "required" used together, throw exception

[chsword]

Description

When JsonIgnoreAttribute and C# required used together, throw exception

    public void TestRequired()
    {
        var model = new TestModel
        {
            Str1 = "a",
            Str2 = "b"
        };
        var json = System.Text.Json.JsonSerializer.Serialize(model);
        Console.WriteLine(json);
    }

    public class TestModel
    {
        [System.Text.Json.Serialization.JsonIgnore]
        public required  string Str1 { get; set; }
        [JsonPropertyName("s_str2")]
        public required string Str2 { get; set; }
    }

Configuration

.NET 7
Windows

Regression?

Other information

System.InvalidOperationException: JsonPropertyInfo 'Str1' defined in type 'LingHuo.SDK.Tests.Tencent.TencentFaceIdH5Test+TestModel' is marked required but does not specify a setter.
    at System.Text.Json.ThrowHelper.ThrowInvalidOperationException_JsonPropertyRequiredAndNotDeserializable(JsonPropertyInfo jsonPropertyInfo)
   at System.Text.Json.Serialization.Metadata.JsonPropertyInfo.Configure()
   at System.Text.Json.Serialization.Metadata.JsonTypeInfo.InitializePropertyCache()
   at System.Text.Json.Serialization.Metadata.JsonTypeInfo.Configure()
   at System.Text.Json.Serialization.Metadata.JsonTypeInfo.<EnsureConfigured>g__ConfigureLocked|143_0()
   at System.Text.Json.JsonSerializerOptions.GetTypeInfoInternal(Type type, Boolean ensureConfigured, Boolean resolveIfMutable)
   at System.Text.Json.JsonSerializer.GetTypeInfo(JsonSerializerOptions options, Type inputType)
   at System.Text.Json.JsonSerializer.GetTypeInfo[T](JsonSerializerOptions options)
   at System.Text.Json.JsonSerializer.Serialize[TValue](TValue value, JsonSerializerOptions options)
   at 

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Issue Details

---

Description

When JsonIgnoreAttribute and C# required used together, throw exception

    public void TestRequired()
    {
        var model = new TestModel
        {
            Str1 = "a",
            Str2 = "b"
        };
        var json = System.Text.Json.JsonSerializer.Serialize(model);
        Console.WriteLine(json);
    }

    public class TestModel
    {
        [System.Text.Json.Serialization.JsonIgnore]
        public required  string Str1 { get; set; }
        [JsonPropertyName("s_str2")]
        public required string Str2 { get; set; }
    }

Configuration

.NET 7
Windows

Regression?

Other information

System.InvalidOperationException: JsonPropertyInfo 'Str1' defined in type 'LingHuo.SDK.Tests.Tencent.TencentFaceIdH5Test+TestModel' is marked required but does not specify a setter.
    at System.Text.Json.ThrowHelper.ThrowInvalidOperationException_JsonPropertyRequiredAndNotDeserializable(JsonPropertyInfo jsonPropertyInfo)
   at System.Text.Json.Serialization.Metadata.JsonPropertyInfo.Configure()
   at System.Text.Json.Serialization.Metadata.JsonTypeInfo.InitializePropertyCache()
   at System.Text.Json.Serialization.Metadata.JsonTypeInfo.Configure()
   at System.Text.Json.Serialization.Metadata.JsonTypeInfo.<EnsureConfigured>g__ConfigureLocked|143_0()
   at System.Text.Json.JsonSerializerOptions.GetTypeInfoInternal(Type type, Boolean ensureConfigured, Boolean resolveIfMutable)
   at System.Text.Json.JsonSerializer.GetTypeInfo(JsonSerializerOptions options, Type inputType)
   at System.Text.Json.JsonSerializer.GetTypeInfo[T](JsonSerializerOptions options)
   at System.Text.Json.JsonSerializer.Serialize[TValue](TValue value, JsonSerializerOptions options)
   at 

Author:	chsword
Assignees:	-
Labels:	area-System.Text.Json
Milestone:	-

[krwq]

This scenario was blocked by design because we won't ever be able to source generate such code (we must provide property when it's required)... You can workaround it by creating contract resolver modifier and removing this property - it will only work with reflection-based serializer though.

Here is a workaround:

using System.Text.Json;
using System.Text.Json.Serialization;
using System.Text.Json.Serialization.Metadata;

JsonSerializerOptions options = new()
{
    TypeInfoResolver = new DefaultJsonTypeInfoResolver()
    {
        Modifiers =
        {
            RemoveIgnoredPropertiesFromContract
        }
    }
};

var model = new TestModel
{
    Str1 = "a",
    Str2 = "b"
};
var json = JsonSerializer.Serialize(model, options);
Console.WriteLine(json);
// {"s_str2":"b"}

static void RemoveIgnoredPropertiesFromContract(JsonTypeInfo typeInfo)
{
    if (typeInfo.Kind != JsonTypeInfoKind.Object)
        return;

    List<JsonPropertyInfo> properties = new();

    foreach (var prop in typeInfo.Properties)
    {
        if (prop.AttributeProvider != null && prop.AttributeProvider.IsDefined(typeof(JsonIgnoreAttribute), inherit: true))
        {
            continue;
        }

        properties.Add(prop);
    }

    typeInfo.Properties.Clear();

    foreach (var property in properties)
    {
        typeInfo.Properties.Add(property);
    }
}

public class TestModel
{
    [JsonIgnore]
    public required string Str1 { get; set; }
    [JsonPropertyName("s_str2")]
    public required string Str2 { get; set; }
}

I'm closing this as by design though.