EF Core 7 SQL Server JsonColumn可空布尔值存为字符串致反序列化失败

环境信息 #

已安装的NuGet包：

<PackageReference Include="Microsoft.EntityFrameworkCore" Version="7.0.8" />
<PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="7.0.8" />
<PackageReference Include="Microsoft.EntityFrameworkCore.Relational" Version="7.0.8"/>
<PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="7.0.8" />

实体与上下文配置 #

实体类定义 #

class B
{
  public bool? B1 { get; set; } = false;
  public bool? B2 { get; set; } = false;
  public E1? SomeEnum { get; set; } = SomeEnum.SomeValue;
}

DbContext配置 #

builder.Entity<A>(a =>
{
    a.OwnsOne(a => a.B, ownedNavigationBuilder =>
    {
        ownedNavigationBuilder.ToJson();
        ownedNavigationBuilder
            .Property(x => x.Y)
            .HasConversion(new EnumToNumberConverter<SomeEnum, int>());
    });
});

问题详情 #

已通过EnumToNumberConverter将枚举转换为整数存储，这部分功能正常。但现在遇到新问题：保存包含B类型字段的实体A时，布尔值会被存储为字符串形式（如"true"、"false"），后续读取时抛出反序列化异常：

The JSON value could not be converted to System.Nullable`1[System.Boolean]. Path: $ | LineNumber: 0 | BytePositionInLine: 7.

查看数据库中存储为nvarchar的B列内容，发现布尔值存在两种格式：

{
    B1: true,
    B2: "true"
}

手动将"true"替换为true后，读取操作恢复正常。

完整调用堆栈如下：

An exception occurred while iterating over the results of a query for context type 'Management.Infra.ManagementContext'.
System.Text.Json.JsonException: The JSON value could not be converted to System.Nullable`1[System.Boolean]. Path: $ | LineNumber: 0 | BytePositionInLine: 7.
 ---> System.InvalidOperationException: Cannot get the value of a token type 'String' as a boolean.
   at System.Text.Json.ThrowHelper.ThrowInvalidOperationException_ExpectedBoolean(JsonTokenType tokenType)
   at System.Text.Json.Serialization.Converters.BooleanConverter.Read(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options)
   at System.Text.Json.Serialization.Converters.NullableConverter`1.Read(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options)
   at System.Text.Json.Serialization.JsonConverter`1.TryRead(Utf8JsonReader& reader, Type typeToConvert, JsonSerializerOptions options, ReadStack& state, T& value)
   at System.Text.Json.Serialization.JsonConverter`1.ReadCore(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
   --- End of inner exception stack trace ---
   at System.Text.Json.ThrowHelper.ReThrowWithPath(ReadStack& state, Utf8JsonReader& reader, Exception ex)
   at System.Text.Json.Serialization.JsonConverter`1.ReadCore(Utf8JsonReader& reader, JsonSerializerOptions options, ReadStack& state)
   at System.Text.Json.JsonSerializer.ReadFromSpan[TValue](ReadOnlySpan`1 utf8Json, JsonTypeInfo jsonTypeInfo, Nullable`1 actualByteCount)
   at System.Text.Json.JsonSerializer.ReadUsingMetadata[TValue](JsonElement element, JsonTypeInfo jsonTypeInfo)
   at lambda_method514(Closure , QueryContext , Object[] , JsonElement )
   at lambda_method513(Closure , QueryContext , DbDataReader , ResultContext , SplitQueryResultCoordinator )
   at Microsoft.EntityFrameworkCore.Query.Internal.SplitQueryingEnumerable`1.AsyncEnumerator.MoveNextAsync()

临时处理方案（更新） #

将B类中的可空布尔属性移除?改为非可空类型后，由于部分已存储的JSON缺少对应字段，读取时仍报错。运行迁移脚本补全所有JSON字段后，读写操作恢复正常。

推测这是EF Core 7中JSON列处理可空布尔值时的序列化/反序列化Bug。但该方案存在局限性：后续向B类添加新字段时，都需要编写JSON_MODIFY的SQL迁移脚本。目前正在尝试复现问题，计划复现后向GitHub提交Issue。

内容的提问来源于stack exchange，提问作者Juan Carlos