[wp-trac] [WordPress Trac] #49286: Function get_core_updates() in update-core.php can return an empty array

[WordPress Trac]

#49286: Function get_core_updates() in update-core.php can return an empty array
-----------------------------------+---------------------------------------
 Reporter:  citizenrepresentative  |      Owner:  (none)
     Type:  defect (bug)           |     Status:  new
 Priority:  normal                 |  Milestone:  Awaiting Review
Component:  Administration         |    Version:
 Severity:  normal                 |   Keywords:  needs-testing needs-patch
  Focuses:                         |
-----------------------------------+---------------------------------------
 The function **get_core_updates()** in ''update-core.php'' can return an
 empty array.
 The problem is mostly that in core_upgrade_preamble(), the array is
 immediately assumed to exist, e.g.:
 {{{#!php
 $updates    = get_core_updates();
 if ( ! isset( $updates[0]->response ) || 'latest' == $updates[0]->response
 ) {
 }}}

 The results show up in an error:

  Notice: Trying to get property 'locale' of non-object in
 /usr/share/wordpress/wp-admin/update-core.php on line 40
  Call Stack
  #      Time    Memory  Function        Location
  1      0.0027  404456  {main}( )       .../update-core.php:0
  2      0.1087  2873240 core_upgrade_preamble( )        .../update-
 core.php:695
  3      0.1117  2966944 list_core_update( )     .../update-core.php:230

 I believe the assumption that **get_core_updates()** returns a non-empty
 array is made in other core files as well.

 A check an empty variable seems useful and non-intrusive, since this is an
 update check and not a critical function.

 ''**Conditions:** WordPress 5.2.2, Ubunutu 19, apache, mysql packaged
 install with multi-site active, with the wp-content and wp-config-*.php
 files located in outside directories.''

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Ticket URL: <https://core.trac.wordpress.org/ticket/49286>
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