[wp-meta] [Making WordPress.org] #6612: Prepare for bumping the recommended PHP version to 8.0+

[Making WordPress.org]

#6612: Prepare for bumping the recommended PHP version to 8.0+
----------------------------+--------------------
 Reporter:  SergeyBiryukov  |      Owner:  (none)
     Type:  task (blessed)  |     Status:  new
 Priority:  normal          |  Milestone:
Component:  General         |   Keywords:
----------------------------+--------------------
 Background: #6432.

 Bumping the recommended version for WordPress core to PHP 8.0+ was briefly
 discussed in #6432 as something to be re-evaluated after the WordPress 6.1
 release.

 For context, the relevant ServeHappy API constants are:
 * `RECOMMENDED_PHP` is the latest branch of PHP which WordPress.org
 recommends.
 * `SUPPORTED_PHP` is the lowest branch of PHP which is actively supported.
 * `SECURE_PHP` is the lowest branch of PHP which is receiving security
 updates.
 * `ACCEPTABLE_PHP` is the lowest branch of PHP which is still considered
 "acceptable" in WordPress. Sites with a version lower than this will see
 the ServeHappy dashboard widget urging them to update.

 At the moment, all four are set to PHP 7.4, which is no longer accurate.
 Now that [https://www.php.net/supported-versions.php PHP 7.4 is no longer
 supported] as of     28 Nov 2022, the correct values would ''technically''
 be:
 * `RECOMMENDED_PHP: 8.1` (as only versions with active support should be
 recommended)
 * `SUPPORTED_PHP: 8.1` (as this is the version with active support)
 * `SECURE_PHP: 8.0` (as it still has security support until 26 Nov 2023)
 * `ACCEPTABLE_PHP: 8.0` (as users should see an update prompt if using an
 older, unsupported version, e.g. 7.4)

 Bumping the `SUPPORTED_PHP`, `SECURE_PHP`, and `ACCEPTABLE_PHP` values
 would technically be the correct thing to do. However, bumping them
 separately from `RECOMMENDED_PHP` would result in a weird user experience
 of displaying a "PHP Update Recommended" dashboard widget for PHP 7.4,
 while at the same time stating that 7.4 is the minimum recommended version
 (see the [attachment:6432.php-update-recommended-7.4.x.png:ticket:6432
 screenshot]). So it would be clearer to bump them all when
 `RECOMMENDED_PHP` is also unblocked from being bumped to 8.0+.

 Some of the biggest concerns with bumping the recommended version to 8.0+
 are:
 * Incomplete test coverage for WordPress core.
 * Unknown state of plugin and theme compatibility.

 While the former is a work in progress, @azaozz suggested some ideas to
 help with the latter:
 > Been wondering if we can come up with some automated testing. Perhaps a
 script that installs 100 plugins at a time (in a Docker install), then
 activates them one by one to confirm no errors or warnings. It's far from
 a full testing but is a start...
 >
 > Also maybe something "special" in the plugins and themes repo to
 indicate PHP 8 compatibility? Even a feedback that can be added by users
 (i.e. attempt to crowd source it). May work for the more popular plugins
 :)
 >
 > Probably worth a meta ticket to come up with ideas/have a place for a
 discussion.

 This ticket aims to start the discussion on the prerequisites for updating
 the recommended version to PHP 8.0+.

-- 
Ticket URL: <https://meta.trac.wordpress.org/ticket/6612>
Making WordPress.org <https://meta.trac.wordpress.org/>
Making WordPress.org