How to reliably check if top-level field

[Wedrix]

Hello. Any ideas on how I can reliably check if a field is a top-level field in a resolver? Preferably using the $info parameter. I considered matching the field name to either 'mutation,' 'query,' or 'subscription,' but that's not guaranteed since it's possible for the schema to have fields with these names. Another alternative is to compare the $root param with the $rootValue passed in GraphQL::executeQuery() but that is also not guaranteed. Was wondering if there is a property I can check on the parent type $info->parentType or something along those lines?

[spawnia]

graphql-php/src/Type/Definition/ResolveInfo.php

Lines 57 to 62 in e411398

	/**
	* Parent type of the field being resolved.
	*
	* @api
	*/
	public ObjectType $parentType;

Use $resolveInfo->parentType->name and check if it is equal to Query, Mutation or Subscription - works as long as you do not change the default names of the root types.

[Wedrix]

Thanks for the reply, @spawnia, but what if the schema has Object types with those names? It seems the spec does not reserve them. I'm working on a package therefore I cannot guarantee such types will not be defined in the schema.

[spawnia]

I guess you would have to get a reference to the users Schema and compare against the root types configured there. Alternatively, add some custom configuration option or simply do not support non-default root types.

[Wedrix]

@spawnia, what do you think of this approach count($this->info->path) === 1? Seems like it will only work for top-level fields.

[spawnia]

That seems entirely reasonable! I would be open to accepting a pull request to add a method or field to ResolveInfo to make this easier.

[Wedrix]

count($this->info->path) === 1