Version 4.6.0

system/3rd_party/graphql-php/Validator/Rules/SingleFieldSubscription.php

@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+namespace GraphQL\Validator\Rules;
+
+use GraphQL\Error\Error;
+use GraphQL\Language\AST\NodeKind;
+use GraphQL\Language\AST\NodeList;
+use GraphQL\Language\AST\OperationDefinitionNode;
+use GraphQL\Language\Visitor;
+use GraphQL\Language\VisitorOperation;
+use GraphQL\Validator\ValidationContext;
+use function array_splice;
+use function count;
+use function sprintf;
+
+class SingleFieldSubscription extends ValidationRule
+{
+    /**
+     * @return array<string, callable>
+     */
+    public function getVisitor(ValidationContext $context) : array
+    {
+        return [
+            NodeKind::OPERATION_DEFINITION => static function (OperationDefinitionNode $node) use ($context) : VisitorOperation {
+                if ($node->operation === 'subscription') {
+                    $selections = $node->selectionSet->selections;
+
+                    if (count($selections) !== 1) {
+                        if ($selections instanceof NodeList) {
+                            $offendingSelections = $selections->splice(1, count($selections));
+                        } else {
+                            $offendingSelections = array_splice($selections, 1);
+                        }
+
+                        $context->reportError(new Error(
+                            self::multipleFieldsInOperation($node->name->value ?? null),
+                            $offendingSelections
+                        ));
+                    }
+                }
+
+                return Visitor::skipNode();
+            },
+        ];
+    }
+
+    public static function multipleFieldsInOperation(?string $operationName) : string
+    {
+        if ($operationName === null) {
+            return sprintf('Anonymous Subscription must select only one top level field.');
+        }
+
+        return sprintf('Subscription "%s" must select only one top level field.', $operationName);
+    }
+}