Optimized implementation to interfaces loading

[mcg-web]

• Optimized implementation to interfaces using lazy loader.
• Union types now accepting callback

[vladar]

I am ready yo merge this, but just curious - what is your use case that requires lazy initialization of interface implementations?

[mcg-web]

The use case is simple, let say we have this:

interface A {}
type B implement A {}

$b = new ObjectType([
      "name" => "B",
      "fields" => [/*...*/],
      "interfaces" => function() { /* Some Magic loader */ },
]);

$a = new InterfaceType([
      "name" => "A",
      "fields" => [/*...*/],
]);

This will not work because B is declared before A...
The Lazy Loader allow this, because objects interfaces will be treated only when really needed in the schema.

[vladar]

Yeah, looks like you are right. I will also rework test case for interface definition via Closure to check for this.

[mcg-web]

Yes the test will help for no BC on later modifications 👍