[wp-trac] [WordPress Trac] #47415: is_network_admin() is not checking if the context install is a multisite - documentation improvement

[WordPress Trac]

#47415: is_network_admin() is not checking if the context install is a multisite -
documentation improvement
-------------------------------------------------+-------------------------
 Reporter:  svovaf                               |       Owner:  (none)
     Type:  enhancement                          |      Status:  new
 Priority:  normal                               |   Milestone:  Future
                                                 |  Release
Component:  Networks and Sites                   |     Version:
 Severity:  minor                                |  Resolution:
 Keywords:  good-first-bug has-patch needs-      |     Focuses:  docs,
  refresh                                        |  multisite
-------------------------------------------------+-------------------------

Comment (by svovaf):

 Starting from WP 5.2, where the error catch mechanism was introduced, we
 have started to receive complaints about `get_blog_list()` as a non-
 defined function:

 > Fatal error: Uncaught Error: Call to undefined function get_blog_list()

 After troubleshooting a few live sites that encountered the issue we found
 that something in core's background logic (could be the updates mechanism
 or some WP Cron) is triggering a call to the network-level path, even
 though the sites were not set to work as a multi-site network. Since some
 of our code's logic assumed that `is_network_admin()` can only return
 `true` when running within a network environment, the following logic
 eventually have fallen back to use `get_blog_list()` which like the rest
 of the network functions are not defined as `ms-blogs.php` and `ms-
 deprecated.php` aren't included into the execution sequence on a non-
 network environment:

 {{{#!php
 <?php
             if ( function_exists( 'get_sites' ) ) {
                 // For WP 4.6 and above.
                 return get_sites( $args );
             } else if ( function_exists( 'wp_get_sites' ) ) {
                 // For WP 3.7 to WP 4.5.
                 return wp_get_sites( $args );
             } else {
                 // For WP 3.6 and below.
                 return get_blog_list( 0, 'all' );
             }
 }}}

 Hope it helps.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/47415#comment:3>
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