[wp-trac] [WordPress Trac] #61468: DivisionByZero issue for comments on PHP8.0+

[WordPress Trac]

#61468: DivisionByZero issue for comments on PHP8.0+
----------------------------+-----------------------------
 Reporter:  hideandgeek404  |      Owner:  (none)
     Type:  defect (bug)    |     Status:  new
 Priority:  normal          |  Milestone:  Awaiting Review
Component:  Comments        |    Version:  trunk
 Severity:  major           |   Keywords:
  Focuses:                  |
----------------------------+-----------------------------
 === Quick summary

 I have found an issue with PHP 8.0+ where if the `comments_per_page`
 option is set to 0, which really shouldn't be possible, PHP 8.0+ fires a
 DivisionByZero exception. This means that any blog post with the comments
 section and form showing then hits a fatal error.


 === Steps to reproduce

 1. Set the site's PHP version to 8.0+
 2. Visit `Settings > Discussion` and set the `Break comments into pages
 with x` option to 0.
 3. Save changes
 4. Visit a blog post with comments active
 5. See the blank post and fatal error in the logs

 === A clear and concise description of what you expected to happen.

 The blog post should load and show any existing comments above the comment
 form.

 === What actually happened

 When comments are activated on blog posts, loading the blog post in the
 front end causes a blank screen and a fatal error in the logs.

 {{{
 PHP Fatal error:  Uncaught DivisionByZeroError: Division by zero in
 /wordpress/core/6.5.4/wp-includes/comment-template.php:1520
 }}}

 In `wp-includes/comment-template.php` on line 1520 we find this code:

 {{{
 $comment_args['offset'] = ( (int) ceil( $top_level_count / $per_page ) - 1
 ) * $per_page;
 }}}

 If the `comments_per_page` option is always going to be used for this
 math, it should not be possible to set it to zero in `Settings >
 Discussion`.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/61468>
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