[wp-trac] [WordPress Trac] #12754: register_uninstall_hook() doesn't allow multiple callbacks

[WordPress Trac]

#12754: register_uninstall_hook() doesn't allow multiple callbacks
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 Reporter:  scribu        |       Owner:  westi    
     Type:  defect (bug)  |      Status:  new      
 Priority:  normal        |   Milestone:  3.0      
Component:  Plugins       |     Version:  3.0      
 Severity:  normal        |    Keywords:  has-patch
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Comment(by nacin):

 A deactivation hook is run when the plugin is deactivated. That means that
 the plugin is already activated and thus already included. The
 deactivation callback is then run and the active_plugins option is updated
 to remove the plugin for the next page load.

 The uninstall hook may be run on a plugin that is not active, and thus not
 included. The way it currently works, is you can run
 register_uninstall_hook() on activation. By global scope, I meant on
 inclusion. It works both on a regular hook like init and on a one-off like
 activation.

 If there's no conditional case involved, then there's little reason to
 keep updating the database option, so on activation is fine. But, if you
 were running it on the init hook, that hook is already fired by the time a
 deactivated plugin file is included for the uninstall callback to be run.
 That means no callback would be registered.

 So, the only way the patch would work is if it is run in global scope.
 This may be a requirement for register_activation_hook(), but it is not a
 requirement for register_uninstall_hook(), which works perfectly fine if
 done only on activation. I'm not speaking for the original developer or
 committer, of course -- that could have been the idea.

 I just searched briefly through the plugin directory and found a number of
 plugins using it in global scope, but I also found a few that did it on
 init, activation, or admin_init.

 > So, as long as the plugin includes the file with the callback(s), it
 doesn't matter where they are.
 Sure, and that's a good practice, but if for whatever reason you wanted to
 keep the function in a separate file (and not use uninstall.php, for
 whatever reason) and use register_uninstall_hook(), that would no longer
 work under your patch, as register_uninstall_hook() would not be fired.
 Sure, that's a silly use case. I was just pointing out that you were
 making an assumption.

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Ticket URL: <http://core.trac.wordpress.org/ticket/12754#comment:7>
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