check for Introspection::TYPE_NAME_FIELD_NAME in QueryPlan::analyzeSelectionSet at wrong place?

[jmglsn]

Hi over there,

I'll try to provide more details soon, maybe also an query where the essential problem is visible.
Right now I just have a huge query which is hard to reduce to the key point.

But maybe it's also just moving an assertion.

In QueryPlan::analyzeSelectionSet is an assertion that aims for $parentType instanceof HasFieldsType just a few lines below is a condition that skips the current iteration if the field name is Introspection::TYPE_NAME_FIELD_NAME.
I ran into an error because the $selectionNode is a Introspection::TYPE_NAME_FIELD_NAME - so its not an HasFieldsType.

Could we move the assertion below the check for Introspection::TYPE_NAME_FIELD_NAME?

Thank you :)

    private function analyzeSelectionSet(SelectionSetNode $selectionSet, Type $parentType, array &$implementors): array
    {
        $fields = [];
        $implementors = [];
        foreach ($selectionSet->selections as $selectionNode) {
            if ($selectionNode instanceof FieldNode) {
                $fieldName = $selectionNode->name->value;

                if ($fieldName === Introspection::TYPE_NAME_FIELD_NAME) {
                    continue;
                }

                // now assert
                assert($parentType instanceof HasFieldsType, 'ensured by query validation');
// ...

[jmglsn]

If I got it correctly the following could be used to describe the problem:

query {
   aQuery {
     aUnionType {
       __typename
     }
   }
}

Within the resolver for aQuery I try to access the query plan by calling $resolveInfo->lookAhead()->queryPlan().
This will cause analyzeQueryPlan with analyzeSelectionSet and a call from analyzeSubFields with an instance of UnionType (passes over $type instanceof AbstractType).
The UnionType instance will than cause an error for $parentType instanceof HasFieldsType.

[spawnia]

Thanks for the detailed report, fixed with https://github.com/webonyx/graphql-php/releases/tag/v15.0.2.

[jmglsn]

Thank you for the super fast response! 🥇