Site-kit-wp: call_user_func warnings raised when using wp-cli

[majemedia]

Bug Description

$ wp plugin list
Warning: call_user_func() expects parameter 1 to be a valid callback, array must have exactly two members in wp-includes/rest-api/class-wp-rest-server.php on line 1165
Warning: call_user_func() expects parameter 1 to be a valid callback, array must have exactly two members in wp-includes/rest-api/class-wp-rest-server.php on line 1165

$ wp plugin list --skip-plugins=google-site-kit
no warnings

Steps to reproduce

1. Run wp plugin list
   
   
   
   • see warnings above plugin list table
   
   
2. Run wp plugin list --skip-plugins=google-site-kit
   
   
   
   • no warnings above plugin list table
   
   

Additional Context

This seems to be environment specific and I can't duplicate on a server running PHP 7.4 (shrug)

• PHP CLI Version: PHP 7.2.24-0ubuntu0.18.04.3 (cli)
• PHP FPM Version: v7.2.24-0ubuntu0.18.04.3
• Server: DISTRIB_DESCRIPTION="Ubuntu 18.04.4 LTS"
• WP Cli Version: 2.4.0
• WP Core version: 5.3.2
• Google Site Kit: 1.4.0 (also reproduced on 1.3.1)

I DO have opcache enabled for fpm & cli on the affected server but when I turned it off I still got the warnings.

---

_Do not alter or remove anything below. The following sections will be managed by moderators only._

Acceptance criteria

• The REST API should not trigger a PHP warning due to Site Kit.
• Site Kit should provide REST API response schemas as expected by WordPress core.

Implementation Brief

• Update \Google\Site_Kit\Core\Modules\Modules::get_module_schema method to return a closure that returns the schema itself.

QA Brief

• Install and activate woocommerce
• With Site Kit active, run wp plugin list
• See no warnings above table output

Changelog entry

• Fix PHP warning that could occur when retrieving REST API information via help endpoint.

[lbonomo]

Hi.
I have the same problem, only together WooCommerce.
I see this "warning" when add a "new REST_Route()" with "schema". Example "... 'schema' => $this->get_module_schema()..." in line 583 of file google-site-kit/includes/Core/Modules/Modules.php

[AgileIT]

Hi,
I have the same problem. Error with WooCommerce for each wp-cli request.
Warning: call_user_func() expects parameter 1 to be a valid callback, array must have exactly two members in www/wp-includes/rest-api/class-wp-rest-server.php on line 1244 (x3)

[cole10up]

Passing this to level 2 as I don't have a host with CLI setup to try this one

[extremeshok]

receiving a similar error

root@5273c015a93e:# wp-cli --allow-root --path=/var/www/vhosts/html/ cache flush                                                 
Warning: call_user_func() expects parameter 1 to be a valid callback, array must have exactly two members in /var/www/vhosts/html/wp-includes/rest-api/class-wp-rest-server.php on line 1244
Warning: call_user_func() expects parameter 1 to be a valid callback, array must have exactly two members in /var/www/vhosts/html/wp-includes/rest-api/class-wp-rest-server.php on line 1244
Warning: call_user_func() expects parameter 1 to be a valid callback, array must have exactly two members in /var/www/vhosts/html/wp-includes/rest-api/class-wp-rest-server.php on line 1244
Success: The cache was flushed.

[eugene-manuilov]

@felixarntz Looks like the bug still exists in the latest vesion of the plugin. The issue happens here:

https://github.com/google/site-kit-wp/blob/25642bc9aff64bc38e4d18739a92f15eec69ad6c/includes/Core/Modules/Modules.php#L496
https://github.com/google/site-kit-wp/blob/25642bc9aff64bc38e4d18739a92f15eec69ad6c/includes/Core/Modules/Modules.php#L556
https://github.com/google/site-kit-wp/blob/25642bc9aff64bc38e4d18739a92f15eec69ad6c/includes/Core/Modules/Modules.php#L584

The $this->get_module_schema() function returns schema array, but the rest server class expects it to be a function that returns the schema. To fix it we need to wrap get_module_schema calls with anonymous functions, something like this:

new REST_Route(
    'core/modules/data/list',
    array(
        array(
            'methods' => WP_REST_Server::READABLE,
            'callback'  => function( WP_REST_Request $request ) {
                $modules = array_map(
                    array( $this, 'prepare_module_data_for_response' ),
                    $this->get_available_modules()
                );
                return new WP_REST_Response( array_values( $modules ) );
            },
            'permission_callback' => $can_authenticate,
        ),
    ),
    array(
        'schema' => function() {
            return $this->get_module_schema();
        },
    )
),

Or we can make get_modules_schema to be public and then we cau make it to be callable:

array(
    'schema' => array( $this, 'get_module_schema' ),
)

[felixarntz]

Thanks @eugene-manuilov, let's fix this for the next release.

[eugene-manuilov]

@felixarntz could you please check my IB? Is there anything you want me to add/update?

[felixarntz]

@eugene-manuilov IB looks good, except let's keep the method private and pass a closure to schema instead, which calls the method (tentative IB ✅ ).

If that's okay with you, feel free to just make that adjustment and move directly to execution.

[eugene-manuilov]

Ok, updated. Moving to the execution.

[cole10up]

Tested

Built latest develop, installed SK and Woocommerce, activated both.

Checked wp plugin list

No errors to report.

Passed QA ✅