[wp-trac] [WordPress Trac] #59956: author feed having an issue on latest WP6.4 version

[WordPress Trac]

#59956: author feed having an issue on latest WP6.4 version
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 Reporter:  janareddy          |       Owner:  (none)
     Type:  defect (bug)       |      Status:  assigned
 Priority:  normal             |   Milestone:  Awaiting Review
Component:  Feeds              |     Version:  6.4
 Severity:  major              |  Resolution:
 Keywords:  reporter-feedback  |     Focuses:
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Changes (by hellofromTonya):

 * keywords:   => reporter-feedback


Comment:

 Hello @janareddy,

 Welcome back to WordPress Core's Trac :) Thank you for opening this ticket
 and referencing [https://wordpress.org/support/topic/having-an-issue-on-
 author-feed-on-wp-6-4/ the discussion in the support ticket].

 >as per little debug it seems in feed.php on line number 720 max() command
 having issue , its expecting array but date string is passing.

 Hmm, I'm not seeing how a string is being passed to `max()` in the
 `get_feed_build_date()` function as `$modified_times` will always be an
 array. But that said, the error you noted indicates `$modified_times` is
 an empty array.

 Passing an empty array to `max()` is a Warning on < PHP 8 or a
 `ValueError` on >= PHP 8. See it in action https://3v4l.org/AaEOD and more
 information is available [https://www.php.net/manual/en/function.max.php
 in the PHP manual].

 Looking at the code, this area of the code runs when there are posts to
 process.  `$modified_times` will contain an array of the posts'
 `'post_modified_gmt'` values. For `$modified_times` to be an empty array,
 the data in `$wp_posts->posts` would either be empty or not have
 `'post_modified_gmt'` field / value.

 I'm not seeing how this was introduced in 6.4 specifically. Wondering if
 the issue was existed on your site(s) previously, maybe as a PHP Warning
 in your server logs.

 To help contributors investigate and reproduce the issue, need some more
 information please:

 >if you see the live feed page
 https://spearswms.com/author/janechurch/feed/ this is running on WP6.1 and
 no issue. when we update to WP6.4 on Dev branch.

 * Was the site previously on WP 6.1 also running on PHP 8? Or was the
 upgrade to WP 6.4 along with upgrading to PHP 8?

 * On the sites not running WP 6.4, are there PHP Warnings for `max()` in
 the server logs?

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Ticket URL: <https://core.trac.wordpress.org/ticket/59956#comment:2>
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