[System.Text.Json]: Recursive property in collection type results in stackoverflow

[pranavkm]

static void Main(string[] args)
{
    var node = new Node();
    Console.WriteLine(JsonSerializer.ToString(node));
}

class Node
{
    public List<Node> Children { get; set; }
}

Environment: Microsoft.NETCore.App 3.0.0-preview6-27629-07

[pranavkm]

cc @steveharter \ @ahsonkhan

[steveharter]

Duplicate of https://github.com/dotnet/corefx/issues/36510

[pranavkm]

@steveharter the other issue is for a cycle in the serialization graph. However, in this case, there isn't an actual cyle in fact, Children` node is entirely empty and has no back reference to the parent. I would expect this to serialize just normally.

[pranavkm]

Can we prioritize fixing this issue? There is really no good way to workaround this and it's a fairly recurring theme in our tests.

[rynowak]

To put some emphasis on this - this is blocking us using S.T.J for Blazor. https://github.com/aspnet/AspNetCore/pull/10171/files#diff-5fd50c61f956f92c8ba798028bb6cce7R41

[rynowak]

I'm guessing that the call stack for this is something like:

JsonSerializerOptions.GetOrAddClass()
JsonPropertyInfo.ctor()
..Activator..
JsonClassInfo.CreateProperty()
JsonClassInfo.AddProperty()
JsonClassInfo.ctor()

https://github.com/dotnet/corefx/blob/master/src/System.Text.Json/src/System/Text/Json/Serialization/JsonPropertyInfo.cs#L66

It looks like the case of "T has a property of type IEnumerable<T>" will recursively try to construct the class info for itself. The infinite recursion could be broken by make this lazy or keeping track of the work "on the stack" using a local HashSet<> in GetOrAddClass().

[ahsonkhan]

From @oskardudycz in https://github.com/dotnet/corefx/issues/37610

As in title: Serializing class that has array of children of the same class throws StackOverflowException.

Simplest repro steps:

public class TestClass
{
    public TestClass[] Children { get; set; }
}

var document = new TestClass();
var str = JsonSerializer.ToString(document);

I create repository that reproduces this issue: https://github.com/oskardudycz/System.Text.Json.Fail