[wp-trac] [WordPress Trac] #18405: Check if pluggable function was already defined by other plugin

[WordPress Trac]

#18405: Check if pluggable function was already defined by other plugin
-------------------------+------------------------------
 Reporter:  F J Kaiser   |       Owner:
     Type:  enhancement  |      Status:  new
 Priority:  normal       |   Milestone:  Awaiting Review
Component:  Plugins      |     Version:
 Severity:  normal       |  Resolution:
 Keywords:               |
-------------------------+------------------------------

Old description:

> Currently there's no way to check if a pluggable function is already
> defined by some other plugin in a normal single site WP installation.
>
> With the current design "pluggables" are only ''really pluggable'' for
> your own installations. Hosting a plugin the redefines a pluggable
> function in the official repository will only lead to lots of problems
> and unsatisfied/angry users that run into non-debugable errors.
>
> The problem is that there's no standartized way to check if the function
> was already defined. Imho there ''should'' be a hook to allow for save
> checking if the function was defined and then throw something like a
> {{
> _doing_it_wrong();
> }}
> -message, visible only for developers.
>
> Sample plugin (for a multisite installation) to test and discuss this.
>

> {{{
> /*
> Plugin Name:    ___Pluggable Test
> Plugin URI:             ___
> Description:    ___
> Author:                 ___
> Author URI:     ___
> Version:                0.1
> License:                ___
> */
> function wp_rand( $min = 0, $max = 0 )
> {
>         return 'I am just a test';
> }
>
> function trac_test_the_hook()
> {
>         $title = 'pluggable test output';
>
>         $msg  = 'The current filter is "'.current_filter().'" and
> works.';
>         if ( function_exists( 'wp_rand' ) )
>                 $msg .= '<br />The function <em>"wp_rand()"</em> was
> already defined elsewhere.';
>
>         wp_die( $msg, $title );
> }
> // Change the 'muplugins_loaded' to test other hooks
> add_action( 'muplugins_loaded', 'trac_test_the_hook', 999 );
> }}}
>

> [1] {wp-hackers thread|https://groups.google.com/forum/?hl=de#!topic/wp-
> hackers/-EJbmkdMLjg]

New description:

 Currently there's no way to check if a pluggable function is already
 defined by some other plugin in a normal single site WP installation.

 With the current design "pluggables" are only ''really pluggable'' for
 your own installations. Hosting a plugin the redefines a pluggable
 function in the official repository will only lead to lots of problems and
 unsatisfied/angry users that run into non-debugable errors.

 The problem is that there's no standartized way to check if the function
 was already defined. Imho there ''should'' be a hook to allow for save
 checking if the function was defined and then throw something like a
 {{{
 _doing_it_wrong();
 }}}
 -message, visible only for developers.

 Sample plugin (for a multisite installation) to test and discuss this.


 {{{
 /*
 Plugin Name:    ___Pluggable Test
 Plugin URI:             ___
 Description:    ___
 Author:                 ___
 Author URI:     ___
 Version:                0.1
 License:                ___
 */
 function wp_rand( $min = 0, $max = 0 )
 {
         return 'I am just a test';
 }

 function trac_test_the_hook()
 {
         $title = 'pluggable test output';

         $msg  = 'The current filter is "'.current_filter().'" and works.';
         if ( function_exists( 'wp_rand' ) )
                 $msg .= '<br />The function <em>"wp_rand()"</em> was
 already defined elsewhere.';

         wp_die( $msg, $title );
 }
 // Change the 'muplugins_loaded' to test other hooks
 add_action( 'muplugins_loaded', 'trac_test_the_hook', 999 );
 }}}


 [1] {wp-hackers thread|https://groups.google.com/forum/?hl=de#!topic/wp-
 hackers/-EJbmkdMLjg]

--

Comment (by dd32):

 See also: #8833 - Pluggable functions shouldn't really be needed, instead,
 all pluggable functions should be a filter set.

-- 
Ticket URL: <http://core.trac.wordpress.org/ticket/18405#comment:1>
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