Merge pull request #3035 from jasonbahl/feat/3034-provide-better-error-when-type-does-not-exist

jasonbahl · web-flow · commit 121a691189fb · 2024-02-08T11:13:30.000-07:00
feat: provide better error when field references a type that does not exist
diff --git a/src/Registry/TypeRegistry.php b/src/Registry/TypeRegistry.php
@@ -2,6 +2,7 @@
 
 namespace WPGraphQL\Registry;
 
+use GraphQL\Error\Error;
 use GraphQL\Type\Definition\Type;
 use WPGraphQL\Data\DataSource;
 use WPGraphQL\Mutation\CommentCreate;
@@ -943,8 +944,21 @@ protected function prepare_field( string $field_name, array $field_config, strin
 				return null;
 			}
 
-			$field_config['type'] = function () use ( $field_config ) {
-				return $this->get_type( $field_config['type'] );
+			$field_config['type'] = function () use ( $field_config, $type_name ) {
+				$type = $this->get_type( $field_config['type'] );
+				if ( ! $type ) {
+					$message = sprintf(
+					/* translators: %1$s is the Field name, %2$s is the type name the field belongs to. %3$s is the non-existent type name being referenced. */
+						__( 'The field \'%1$s\' on Type \'%2$s\' is configured to return \'%3$s\' which is a non-existent Type in the Schema. Make sure to define a valid type for all fields. This might occur if there was a typo with \'%3$s\', or it needs to be registered to the Schema.', 'wp-graphql' ),
+						$field_config['name'],
+						$type_name,
+						$field_config['type']
+					);
+					// We throw an error here instead of graphql_debug message, as an error would already be thrown if a type didn't exist at this point,
+					// but now it will have a more helpful error message.
+					throw new Error( esc_html( $message ) );
+				}
+				return $type;
 			};
 		}
 
diff --git a/tests/wpunit/AccessFunctionsTest.php b/tests/wpunit/AccessFunctionsTest.php
@@ -2338,4 +2338,45 @@ public function testDeRegisterMutationWithUnderscores() {
 		// query should error because the mutation was deregistered
 		self::assertQueryError( $actual, [] );
 	}
+
+	public function testRegisterFieldWithNonExistingTypeReturnsErrorWhenFieldIsReferenced() {
+
+		register_graphql_field( 'User', 'fakeField', [
+			'type' => 'NonExistingType'
+		]);
+
+		// This should query without error because the field doesn't impact types queried here
+		$query_one = '{posts{nodes{id}}}';
+
+		// Should not return error because the field with the invalid type is not being queried for
+		$query_two = '{users{nodes{id}}}';
+
+		// This should return an error because the fakeField is being queried for and it references a non-existent type
+		$query_three = '{users{nodes{id, fakeField}}}';
+
+		$actual = $this->graphql([
+			'query' => $query_one
+		]);
+
+		self::assertQuerySuccessful( $actual, [
+			$this->expectedField( 'posts', self::NOT_NULL ),
+		] );
+
+		$actual_two = $this->graphql([
+			'query' => $query_two
+		]);
+
+		self::assertQuerySuccessful( $actual_two, [
+			$this->expectedField( 'users', self::NOT_NULL ),
+		] );
+
+		// The third query should throw a GraphQL\Error calling out the fact that the field is referencing a non-existent type
+		$this->expectException( GraphQL\Error\Error::class );
+		$this->expectExceptionMessageMatches( "/non-existent/" );
+
+		$actual_three = $this->graphql([
+			'query' => $query_three
+		]);
+
+	}
 }
