[wp-trac] [WordPress Trac] #43583: Introduce new PHP cross-version compat function `is_countable()`

[WordPress Trac]

#43583: Introduce new PHP cross-version compat function `is_countable()`
-------------------------------------------------+-------------------------
 Reporter:  jrf                                  |       Owner:
                                                 |  SergeyBiryukov
     Type:  enhancement                          |      Status:  closed
 Priority:  normal                               |   Milestone:  4.9.6
Component:  General                              |     Version:
 Severity:  normal                               |  Resolution:  fixed
 Keywords:  has-patch has-unit-tests commit      |     Focuses:
  needs-dev-note dev-feedback                    |
-------------------------------------------------+-------------------------
Changes (by ayeshrajans):

 * keywords:  has-patch has-unit-tests commit needs-dev-note => has-patch
     has-unit-tests commit needs-dev-note dev-feedback


Comment:

 I maintain a standalone PHP polyfill for the `is_countable` function, and
 Craig, who was involved in the PHP RFC to bring this function to PHP 7.3
 opened a PR there about an edge-case: https://github.com/Ayesh
 /is_countable-polyfill/pull/4

 Turns out PHP classes added by extensions can internally implement a
 `count_elements` handler that allows PHP engine to successfully return a
 value without triggerring any warnings, which makes all objects from that
 class are countable.

 I tested this with a compiled php-src master.

 The attached patch updates the is_countable compat code and expand its
 test coverage for this edge-case. As of now, `SimpleXMLElement` and
 `ResourceBundle` from Intl extension are the only classes that implement
 this handler. The patch is loosely based on https://github.com/Ayesh
 /is_countable-polyfill/commit/d8c20caa4abd8ef8de5128d3a62d4ee385f51174.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/43583#comment:17>
WordPress Trac <https://core.trac.wordpress.org/>
WordPress publishing platform