GraphQL\Validator\Rules\PossibleFragmentSpreads::doTypesOverlap()

Complexity

Conditions	22
Paths	20

Size

Total Lines	66
Code Lines	23

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	24
CRAP Score	22

Importance

Changes

0

<?php
    private function doTypesOverlap(Schema $schema, CompositeType $fragType, CompositeType $parentType)
    {
        // Checking in the order of the most frequently used scenarios:
        // Parent type === fragment type
        if ($parentType === $fragType) {
            return true;
        }

        // Parent type is interface or union, fragment type is object type
        if ($parentType instanceof AbstractType && $fragType instanceof ObjectType) {
            return $schema->isPossibleType($parentType, $fragType);
        }

        // Parent type is object type, fragment type is interface (or rather rare - union)
        if ($parentType instanceof ObjectType && $fragType instanceof AbstractType) {
            return $schema->isPossibleType($fragType, $parentType);
        }

        // Both are object types:
        if ($parentType instanceof ObjectType && $fragType instanceof ObjectType) {
            return $parentType === $fragType;
        }

        // Both are interfaces
        // This case may be assumed valid only when implementations of two interfaces intersect
        // But we don't have information about all implementations at runtime
        // (getting this information via $schema->getPossibleTypes() requires scanning through whole schema
        // which is very costly to do at each request due to PHP "shared nothing" architecture)
        //
        // So in this case we just make it pass - invalid fragment spreads will be simply ignored during execution
        // See also https://github.com/webonyx/graphql-php/issues/69#issuecomment-283954602
        if ($parentType instanceof InterfaceType && $fragType instanceof InterfaceType) {
            return true;

            // Note that there is one case when we do have information about all implementations:
            // When schema descriptor is defined ($schema->hasDescriptor())
            // BUT we must avoid situation when some query that worked in development had suddenly stopped
            // working in production. So staying consistent and always validate.
        }

        // Interface within union
        if ($parentType instanceof UnionType && $fragType instanceof InterfaceType) {
            foreach ($parentType->getTypes() as $type) {
                if ($type->implementsInterface($fragType)) {
                    return true;
                }
            }
        }

        if ($parentType instanceof InterfaceType && $fragType instanceof UnionType) {
            foreach ($fragType->getTypes() as $type) {
                if ($type->implementsInterface($parentType)) {
                    return true;
                }
            }
        }

        if ($parentType instanceof UnionType && $fragType instanceof UnionType) {
            foreach ($fragType->getTypes() as $type) {
                if ($parentType->isPossibleType($type)) {
                    return true;
                }
            }
        }

        return false;
    }