[wp-trac] [WordPress Trac] #64901: rest_convert_error_to_response() fatals when WP_Error data is a stdClass object in 7.0-beta5

[WordPress Trac]

#64901: rest_convert_error_to_response() fatals when WP_Error data is a stdClass
object in 7.0-beta5
--------------------------+-----------------------------
 Reporter:  nateallen     |      Owner:  (none)
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  REST API      |    Version:
 Severity:  critical      |   Keywords:
  Focuses:  rest-api      |
--------------------------+-----------------------------
 The `rest_convert_error_to_response()` function throws a PHP fatal error
 when a `WP_Error` object contains error data that is a `stdClass` instead
 of an array.

 {{{
 PHP Fatal error: Uncaught Error: Cannot use object of type stdClass as
 array
 in wp-includes/rest-api.php on line 3431
 }}}

 == Cause ==

 In [changeset:61429] (part of the Code Modernization effort, #63430), the
 `isset()` ternary in `rest_convert_error_to_response()` was replaced with
 a null coalescing operator:

 **Before (6.9.4):**
 {{{#!php
 <?php
 return is_array( $error_data ) && isset( $error_data['status'] ) ?
 $error_data['status'] : $status;
 }}}

 **After (7.0-beta5):**
 {{{#!php
 <?php
 return $error_data['status'] ?? $status;
 }}}

 The `is_array()` guard was critical here because
 `WP_Error::get_all_error_data()` can return data of any type, such as
 arrays, objects, strings, integers, etc. Removing it causes a fatal when
 error data is a `stdClass`.

 == Steps to reproduce ==

 Register a REST route that returns a `WP_Error` with `stdClass` data:

 {{{#!php
 <?php
 add_action( 'rest_api_init', function () {
     register_rest_route( 'test/v1', '/trigger-bug', array(
         'methods'             => 'GET',
         'callback'            => function () {
             return new WP_Error(
                 'test_error',
                 'Test error',
                 (object) array( 'status' => 500 )
             );
         },
         'permission_callback' => '__return_true',
     ) );
 } );
 }}}

 Then request `GET /wp-json/test/v1/trigger-bug`.

 == Expected result ==

 A JSON error response (as in 6.9.4).

 == Actual result ==

 PHP fatal error on line 3431 of `wp-includes/rest-api.php`.

 == Suggested fix ==

 Restore the `is_array()` check:

 {{{#!php
 <?php
 return is_array( $error_data ) ? ( $error_data['status'] ?? $status ) :
 $status;
 }}}

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/64901>
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