[wp-trac] [WordPress Trac] #57522: PHP 8.2 > Backend fatal error: PHP Fatal error: Uncaught TypeError

[WordPress Trac]

#57522: PHP 8.2 > Backend fatal error: PHP Fatal error:  Uncaught TypeError
---------------------------------+------------------------------
 Reporter:  mackaaij             |       Owner:  (none)
     Type:  defect (bug)         |      Status:  new
 Priority:  normal               |   Milestone:  Awaiting Review
Component:  General              |     Version:  6.1.1
 Severity:  normal               |  Resolution:
 Keywords:  needs-testing php82  |     Focuses:
---------------------------------+------------------------------

Comment (by SergeyBiryukov):

 Replying to [comment:2 mackaaij]:
 > I filed the report over here as the stack trace seems to list only
 WordPress files (no plugin / theme).

 Right, but it points to [source:tags/6.1.1/src/wp-includes/class-wp-
 hook.php?marks=308#L275 WP_Hook::apply_filters()], which only executes
 code from plugins or themes and does not itself contain the problematic
 `session_start()` call.

 > Any idea how to get to the .php causing the fatal error?

 Code like this, when run in a plugin or a mu-plugin, should display
 information about the current filter, priority, and the attached callbacks
 after the fatal error happens:
 {{{
 register_shutdown_function( 'handle_php_fatal_error' );

 function handle_php_fatal_error() {
         global $wp_filter;

         $last_error = error_get_last();

         if ( $last_error['type'] === E_ERROR ) {
                 $wp_hook  = $wp_filter[ current_filter() ];
                 $priority = $wp_hook->current_priority();

                 echo '<pre>';
                 echo 'Current filter: ' . current_filter() . "\n";
                 echo 'Current priority: ' . $priority . "\n";

                 echo 'Callbacks: ';
                 print_r( array_keys( $wp_hook->callbacks[ $priority ] ) );
                 echo '</pre>';
         }
 }
 }}}

 For example, this is what I get after simulating a fatal error with
 `add_filter( 'the_content', 'session_start' )`:
 {{{
 Current filter: the_content
 Current priority: 10
 Callbacks: Array
 (
     [0] => wptexturize
     [1] => wpautop
     [2] => shortcode_unautop
     [3] => prepend_attachment
     [4] => wp_filter_content_tags
     [5] => wp_replace_insecure_home_url
     [6] => session_start
 )
 }}}

 The displayed function names could then be used to search for the PHP file
 causing the error.

 Alternatively, just searching for `session_start` in the installed plugins
 and active theme would be a good first step.

 > It's not easy for me to disable plugins and switch the theme on this
 specific site, so I hope you have another suggestion.

 I would suggest creating a copy of the site for testing and
 troubleshooting, that way it should be easier to track down the issue than
 working with a live site directly.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/57522#comment:3>
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