Hotchocolate: No compatible constructor found for input type xxx

[grounzero]

Since updating from 10.2.0 during startup when adding my types I get an exception No compatible constructor found for input type: MyUnderlyingType There is no constructor on the type as it just a POCO. I tried commenting out parts to try and locate something more specific but I haven't managed to track it down other than reverting back to 10.2.0 makes it go away.

[grounzero]

Ok It seems to occur because I have a List property on my POCO with no set accessor. If I add a set accessor to the property or when configuring the InputObject to explicitly tell the descriptor to ignore the then it works.

Ideally I just want to change the list by using the Add() and Remove() methods. Is there a way I can do this without ignoring the property or adding a set accessor?

[michaelstaib]

But what would we do when the list is set to null?

BTW, you also can let us pass your read-only props into a constructor.

public class Foo 
{
    public Foo(Bar bar) 
    {
        Bar = bar;
    }

    public Bar Bar { get; }
}

[michaelstaib]

I will close this issue. We will revisit the deserialization again in march after we have the new execution engine in.

[dillanmann]

Is there a way to work around this? E.g. if the type I have as an input type type is in a library I am unable to change, can I specify a way to construct each element, or ignore the property that I know has the wrong accessors?

For the library I am working with there is a class with one property which has a protected setter, I want to be able to ignore this as I cannot change the types library.

[michaelstaib]

If you ignore the property it will not be taken into account. You can either ignore the property with the fluent API or with the GraphQLIgnore Attribute.

In your case I know only the fluent API will work since it is from an external lib.

The question here is why bind a field for input serialization if it cannot be accessed by the serializer?

public class FooInputType : InputType<Foo> 
{
    protected override void Configure(IInputObjectTypeDescriptor<Foo> descriptor) 
    {
        descriptor.Ignore(t => t.Prop);
    }
}

[PascalSenn]

@michaelstaib we already discussed this on slack. @dillanmann did try to ignore it with Ignore but apparently it did not work.

[michaelstaib]

Strange, we will have to write a test for this and verify that this is true and then look what is causing the issue. Anybody wants to do a pr?

Test would go here:
https://github.com/ChilliCream/hotchocolate/blob/master/src/HotChocolate/Core/test/Types.Tests/Types/InputObjectTypeTests.cs

[arif-hanif]

@michaelstaib / @PascalSenn i am running into a similar issue with an external library, I will add the code here, but i am first going to try the fluent API ignore, there are some calculated properties on the class

• Update 09/19/2020 creating an Input type ignoring the properties with no setters or creating a different input type worked

[michaelstaib]

Can you pinpoint what your issue is?

[dillanmann]

FYI I believe I managed to get this working, but the way that I had to ignore it was different than what you specified. I can't remember the exact details, I'll check tomorrow to see what I did for you.