It appears to me that comments_open() is passing the wrong args to apply_filters

[sringwood]

The function comments_open() is passed one argument which may be null ($post_id) which is used to call get_post(). The function get_post() will use the current post if $post_id is null.

The last line of the function comments_open() is

return apply_filters( 'comments_open', $open, $post_id );

Logically in the call it seems to me that $post_id (which may be null) should be $_post->ID to reflect the post returned by the call get_post().

[johnbillion]

Hi @sringwood, welcome to WordPress Trac!

Well spotted, this does appear to be a valid bug. It affects the pings_open() function too.

[lukecavanagh]

@sringwood

https://core.trac.wordpress.org/browser/tags/4.7.3/src/wp-includes/comment-template.php#L1204

[shulard]

Hello guys,

I've just submitted a patch for that little change !

[shulard]

Mistake in diff file, the first one will remove my updates...

[johnbillion]

Thank you, @shulard!

[rachelbaker]

Looks like this also needs a change to the inline docs for the comments_open and pings_open filters since $_post->ID would always be an integer, and never a WP_Post object.

[shulard]

Fix the code and update the filters docs.

[shulard]

@rachelbaker, you are right, I've submitted a new patch with fixed doc too.

[rachelbaker]

Adds conditional to use 0 if $_post->ID is undefined

[rachelbaker]

This might be overkill, but because there is no way to be sure $_post->ID is defined, I added a conditional that will pass 0 to the comments_open() or pings_open() filter for the Post ID. Would love a second opinion on if this conditional is worthy of the edge-case handling. 40286.3.diff​

[shulard]

I though that get_post function will always return an WP_Post instance so $_post->ID will always be defined. It can be null but it's defined ($ID is a public property of WP_Post class).

[rachelbaker]

@shulard get_post() can return null. These two functions can be used anywhere, and cannot assume the post global is populated.

[rachelbaker]

Marking for commit since the change here is also in line with the patches on #40143.

[rachelbaker]

In 40666:

Comments: Correct the $post_id parameter passed to the 'comments_open' and 'pings_open' filters.

Fixes bug where previously the $post_id function argument was passed to the '_open' filters, instead of the result of the get_post() call. If the current post is not found, the $post_id filter parameter will be 0.

Props johnbillion, shulard, rachelbaker.
Fixes #40286.