Add JsonIncludeAttribute & support for non-public accessors

[layomia]

Fixes#29743.
Fixes#34453 (since I'm in this code).

New API approved in #34558.

[Dotnet-GitSync-Bot]

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[steveharter]

Currently this PR assumes that the property is still public, correct?(meaning the setter or getter can be non-public, but not both). Do we have tests with a private property where both setter and getter are private to verify?

[layomia]

Yes, I added some tests showing that non-public properties (with various accessor visibility levels) are not included:

runtime/src/libraries/System.Text.Json/tests/Serialization/PropertyVisibilityTests.cs

Lines 869 to 891 in e4e0585

	[Fact]
	publicstaticvoidNonPublicMembersAreNotIncluded()
	{
	Assert.Equal("{}",JsonSerializer.Serialize(newClassWithNonPublicProperties()));
	stringjson=@"{""MyInt"":1,""MyString"":""Hello"",""MyFloat"":2,""MyDouble"":3}";
	varobj=JsonSerializer.Deserialize<ClassWithNonPublicProperties>(json);
	Assert.Equal(0,obj.MyInt);
	Assert.Null(obj.MyString);
	Assert.Equal(0,obj.GetMyFloat);
	Assert.Equal(0,obj.GetMyDouble);
	}
	privateclassClassWithNonPublicProperties
	{
	internalintMyInt{get;set;}
	internalstringMyString{get;privateset;}
	internalfloatMyFloat{privateget;set;}
	privatedoubleMyDouble{get;set;}
	internalfloatGetMyFloat=>MyFloat;
	internaldoubleGetMyDouble=>MyDouble;
	}

These tests ensure that we throw IOE when [JsonInclude] is used on a non-public properties:

runtime/src/libraries/System.Text.Json/tests/Serialization/PropertyVisibilityTests.NonPublicAccessors.cs

Lines 295 to 330 in e4e0585

	[Theory]
	[InlineData(typeof(ClassWithPrivateProperty_WithJsonIncludeProperty))]
	[InlineData(typeof(ClassWithInternalProperty_WithJsonIncludeProperty))]
	[InlineData(typeof(ClassWithProtectedProperty_WithJsonIncludeProperty))]
	publicstaticvoidNonPublicProperty_WithJsonInclude_Invalid(Typetype)
	{
	InvalidOperationExceptionex=Assert.Throws<InvalidOperationException>(()=>JsonSerializer.Deserialize("",type));
	stringexAsStr=ex.ToString();
	Assert.Contains("MyString",exAsStr);
	Assert.Contains(type.ToString(),exAsStr);
	Assert.Contains("JsonIncludeAttribute",exAsStr);
	ex=Assert.Throws<InvalidOperationException>(()=>JsonSerializer.Serialize(Activator.CreateInstance(type),type));
	exAsStr=ex.ToString();
	Assert.Contains("MyString",exAsStr);
	Assert.Contains(type.ToString(),exAsStr);
	Assert.Contains("JsonIncludeAttribute",exAsStr);
	}
	privateclassClassWithPrivateProperty_WithJsonIncludeProperty
	{
	[JsonInclude]
	privatestringMyString{get;set;}
	}
	privateclassClassWithInternalProperty_WithJsonIncludeProperty
	{
	[JsonInclude]
	internalstringMyString{get;}
	}
	privateclassClassWithProtectedProperty_WithJsonIncludeProperty
	{
	[JsonInclude]
	protectedstringMyString{get;privateset;}
	}

[TanvirArjel]

@layomia Is this available on .NET 5.0 RC1, maybe not. My Project has been updated to .NET 5.0 RC1 but it's not working yet.

public class DataTableParamsDto
{
public int Draw { get; set; }
public int Start { get; set; }
public int Length { get; set; }
public List<ColumnRequestItem> Columns { get; private set; } // Not working
public List<OrderRequestItem> Order { get; private set; } // Not working
public SearchRequestItem Search { get; private set; } // Not working
}

[layomia]

@TanvirArjel the feature is in RC1, but it requires explicitly opting in with JsonIncludeAttribute:

publicclassDataTableParamsDto{publicintDraw{get;set;}publicintStart{get;set;}publicintLength{get;set;}[JsonInclude]publicList<ColumnRequestItem>Columns{get;privateset;}[JsonInclude]publicList<OrderRequestItem>Order{get;privateset;}[JsonInclude]publicSearchRequestItemSearch{get;privateset;}}