Lazy Loading of types is missing a full loading method

[mcg-web]

While trying to introduce lazy loading in the overblog/graphql-bundle, the exception (GraphQL\Error\InvariantViolation: Could not find possible implementing types for Node in schema. Check that schema.types is defined and is an array of all possible types in the schema.) is throw when combining types lazy loading and `assertValid. This exception is throw because when using typeLoader there's no existing method to fully load all types. Here an example:

interface Node {
  id: ID!
}

type Query {
   node(id: String!): Node
}

type Ship implements Node {
   id: String!
   name: String
}

type Ship implements Node {
   id: String!
   name: String
}

type Faction implements Node {
   id: String!
   name: String
}

schema {
  query: Query
}

[vladar]

Actually assertValid loads all types it can extract from the schema (by calling getTypeMap()) internally.

This exception will also happen without lazy-loading because you can't infer all existing types from this schema.

For example, if you start scanning from the Query type, you can only find Node and String. With such schema, you must register all remaining types in types option of the schema.

One way to combine types option with lazy-loading is to pass types as a Closure. It is only called when loading the whole schema (e.g. by assertValid) and won't be called for regular queries.

[mcg-web]

That the idea @vladar 👍 for this solution :)

[vladar]

@mcg-web Yeah, we use it in BuildSchema to create schema from type language. So take a look at this piece of code for reference.

[mcg-web]

thank you @vladar this fix it!