[wp-trac] [WordPress Trac] #12492: Improper use of a variable variable ($$) in remove_all_filters()

[WordPress Trac]

#12492: Improper use of a variable variable ($$) in remove_all_filters()
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 Reporter:  chrisbliss18  |       Owner:  westi                  
     Type:  defect (bug)  |      Status:  new                    
 Priority:  normal        |   Milestone:  3.0                    
Component:  Plugins       |     Version:  3.0                    
 Severity:  normal        |    Keywords:  has-patch tested commit
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 In wp-includes/plugin.php's remove_all_filters function are the following
 lines of code:

 {{{
 if( false !== $priority && isset($$wp_filter[$tag][$priority]) )
     unset($wp_filter[$tag][$priority]);
 }}}

 The $$ is a [http://www.php.net/manual/en/language.variables.variable.php
 variable variable], which is clearly a typo in this case given the next
 line. I first found this when the following warning was generated by
 trying to make use of the priority option of remove_all_actions:

   Notice: Array to string conversion in /opt/lampp/htdocs/trunk/wp-
 includes/plugin.php  on line 225

 Since this amounts to checking for variables of type $false, $10, or any
 other given argument, which won't exist, the second argument is currently
 useless. Thus, until the supplied patch is implemented, it won't be
 possible to use remove_all_filters or remove_all_actions to remove all
 hooks of a specific priority.

 A sample plugin showing this bug is attached. The sample plugin hooks the
 same function to the template_redirect action three times with priorities
 of default, 20, and 30. It then uses the remove_all_actions function
 (which simply calls remove_all_filters) to remove all template_redirect
 hooks for priority 10. This should result in the hooked function being
 called twice, but produces nothing as all the hooks are cleared.

 With my supplied patch applied, the hooked function is called twice,
 echoing "This should render twice." each time. Thus, the expected result
 is achieved with this patch.

-- 
Ticket URL: <http://core.trac.wordpress.org/ticket/12492>
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