[wp-trac] [WordPress Trac] #48059: Check PHP and MySQL requirements as early as possible

[WordPress Trac]

#48059: Check PHP and MySQL requirements as early as possible
----------------------------+-----------------------
 Reporter:  SergeyBiryukov  |      Owner:  (none)
     Type:  defect (bug)    |     Status:  new
 Priority:  normal          |  Milestone:  5.3
Component:  Bootstrap/Load  |    Version:
 Severity:  normal          |   Keywords:  has-patch
  Focuses:                  |
----------------------------+-----------------------
 Background: #47678

 As noted in comment:58:ticket:47678, `wp-includes/plugin.php` cannot
 currently use PHP 5.6+ function signatures. For example, replacing
 `func_get_arg()` in `do_action()` with the spread operator: `do_action(
 $tag, ...$arg )` causes a fatal error on older PHP versions:
 {{{
 Parse error: syntax error, unexpected '.', expecting '&' or T_VARIABLE in
 wp-includes/plugin.php on line 442
 }}}
 instead of displaying a proper error message:
 {{{
 Your server is running PHP version 5.2.17 but WordPress
 5.3-alpha-45282-src requires at least 5.6.20.
 }}}

 Upon some investigation, it looks like the PHP version check is done a bit
 too late in the process flow.

 Just moving the check earlier doesn't help, as
 `wp_load_translations_early()` includes `wp-includes/plugin.php` for
 `do_action()` and `apply_filters()` calls in `l10n.php`.

 Moving the check earlier along with removing
 `wp_load_translations_early()` for this error message appears to work as
 expected. I believe the performance improvements from using modern PHP
 code outweigh the benefits of having this particular string translated.

 At the moment, these 12 files (apart from `wp-settings.php`) need to be
 parsable by older PHP versions to display a proper error message:
 {{{
 wp-includes/load.php
 wp-includes/class-wp-paused-extensions-storage.php
 wp-includes/class-wp-fatal-error-handler.php
 wp-includes/class-wp-recovery-mode-cookie-service.php
 wp-includes/class-wp-recovery-mode-key-service.php
 wp-includes/class-wp-recovery-mode-link-service.php
 wp-includes/class-wp-recovery-mode-email-service.php
 wp-includes/class-wp-recovery-mode.php
 wp-includes/error-protection.php
 wp-includes/default-constants.php
 wp-includes/plugin.php
 wp-includes/version.php
 }}}
 With the patch, the number of files that need to remain parsable by older
 PHP versions is reduced to just two:
 {{{
 wp-includes/version.php
 wp-includes/load.php
 }}}

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/48059>
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