Fix schema built from SDL to return null for unknown types (#1068)

Author: vhenzl

CHANGELOG.md

@@ -68,6 +68,7 @@ You can find and compare releases at the [GitHub release page](https://github.co
 - Preserve extended methods from class-based types in `SchemaExtender::extend()`
 - Fix printing of empty types (#940)
 - Clone `NodeList` in `Node::cloneDeep()`
+- Calling `Schema::getType()` on a schema built from SDL returns `null` for unknown types (#1068)
 
 ### Removed
 

src/Utils/ASTDefinitionBuilder.php

@@ -34,7 +34,6 @@
 use GraphQL\Type\Definition\Type;
 use GraphQL\Type\Definition\UnionType;
 use function is_array;
-use function is_string;
 use Throwable;
 
 /**
@@ -162,6 +161,19 @@ public function buildType($ref): Type
         return $this->internalBuildType($ref->name->value, $ref);
     }
 
+    /**
+     * Calling this method is an equivalent of `typeMap[typeName]` in `graphql-js`.
+     * It is legal to access a type from the map of already-built types that doesn't exist in the map.
+     * Since we build types lazily, and we don't have a such map of built types,
+     * this method provides a way to build a type that may not exist in the SDL definitions and returns null instead.
+     */
+    public function maybeBuildType(string $name): ?Type
+    {
+        return isset($this->typeDefinitionsMap[$name])
+            ? $this->buildType($name)
+            : null
+    }
+
     /**
      * @param (Node&NamedTypeNode)|(Node&TypeDefinitionNode)|null $typeNode
      *

src/Utils/BuildSchema.php

@@ -156,14 +156,14 @@ public function buildSchema(): Schema
         $operationTypes = null !== $schemaDef
             ? $this->getOperationTypes($schemaDef)
             : [
-                'query' => isset($this->nodeMap['Query']) ? 'Query' : null,
-                'mutation' => isset($this->nodeMap['Mutation']) ? 'Mutation' : null,
-                'subscription' => isset($this->nodeMap['Subscription']) ? 'Subscription' : null,
+                'query' => 'Query',
+                'mutation' => 'Mutation',
+                'subscription' => 'Subscription',
             ];
 
         $definitionBuilder = new ASTDefinitionBuilder(
             $this->nodeMap,
-            static function (string $typeName): void {
+            static function (string $typeName): Type {
                 throw self::unknownType($typeName);
             },
             $this->typeConfigDecorator
@@ -198,15 +198,15 @@ static function (string $typeName): void {
 
         return new Schema([
             'query' => isset($operationTypes['query'])
-                ? $definitionBuilder->buildType($operationTypes['query'])
+                ? $definitionBuilder->maybeBuildType($operationTypes['query'])
                 : null,
             'mutation' => isset($operationTypes['mutation'])
-                ? $definitionBuilder->buildType($operationTypes['mutation'])
+                ? $definitionBuilder->maybeBuildType($operationTypes['mutation'])
                 : null,
             'subscription' => isset($operationTypes['subscription'])
-                ? $definitionBuilder->buildType($operationTypes['subscription'])
+                ? $definitionBuilder->maybeBuildType($operationTypes['subscription'])
                 : null,
-            'typeLoader' => static fn (string $name): Type => $definitionBuilder->buildType($name),
+            'typeLoader' => static fn (string $name): ?Type => $definitionBuilder->maybeBuildType($name),
             'directives' => $directives,
             'astNode' => $schemaDef,
             'types' => fn (): array => array_map(

src/Utils/SchemaExtender.php

@@ -580,11 +580,7 @@ public static function extend(
                     ? $def->name->value
                     : null;
 
-                try {
-                    $type = $schema->getType($typeName);
-                } catch (Error $error) {
-                    $type = null;
-                }
+                $type = $schema->getType($typeName);
 
                 if (null !== $type) {
                     throw new Error('Type "' . $typeName . '" already exists in the schema. It cannot also be defined in this type definition.', [$def]);

tests/Type/SchemaTest.php

@@ -123,4 +123,12 @@ public function testIncludesInputTypesOnlyUsedInDirectives(): void
         self::assertArrayHasKey('DirInput', $typeMap);
         self::assertArrayHasKey('WrappedDirInput', $typeMap);
     }
+
+    /**
+     * @see https://github.com/webonyx/graphql-php/issues/997
+     */
+    public function testSchemaReturnsNullForNonexistentType(): void
+    {
+        self::assertNull($this->schema->getType('UnknownType'));
+    }
 }

tests/Utils/BuildSchemaTest.php

@@ -887,6 +887,15 @@ public function testThrowsOnUnknownTypes(): void
 ', null, ['assumeValidSDL' => true])->assertValid();
     }
 
+    /**
+     * @see https://github.com/webonyx/graphql-php/issues/997
+     */
+    public function testBuiltSchemaReturnsNullForNonexistentType(): void
+    {
+        $schema = BuildSchema::build('type KnownType');
+        self::assertNull($schema->getType('UnknownType'));
+    }
+
     public function testSupportsTypeConfigDecorator(): void
     {
         $body = '