Comment meta query is parsed before the pre_get_comments filter

[kasparsd]

Currently it is impossible to use the pre_get_comments filter to adjust the meta_query, because parse_query_vars( $this->query_vars ) is run before the filter is applied http://core.trac.wordpress.org/browser/tags/3.5.1/wp-includes/comment.php#L243:

// Parse meta query
$this->meta_query = new WP_Meta_Query();
$this->meta_query->parse_query_vars( $this->query_vars );

do_action_ref_array( 'pre_get_comments', array( &$this ) );

Comment meta query should be parsed after the pre_get_comments filter has been applied.

Move the pre_get_comments filter before the meta_query parser

Related: [22074] (for #21003).

Unless I'm missing something, the hook appears to be at the correct location. parse_query_vars() can be run again from the hooked function if needed.

The suggested patch would make $this->meta_query object inaccessible for the hooked functions.

Seems like WP_Query has opposite behavior.

Replying to nacin:

Seems like WP_Query has opposite behavior.

WP_Query parses the meta query after the 'pre_get_posts' gets applied: http://core.trac.wordpress.org/browser/tags/3.5.1/wp-includes/query.php#L1934. And it makes sense, because you would need to manually run $query->meta_query->parse_query_vars( $query->query_vars ); every time you modify something related to the meta query.

Replying to SergeyBiryukov:

The suggested patch would make $this->meta_query object inaccessible for the hooked functions.

Exactly, just like WP_Query doesn't make the parsed meta_query available on pre_get_posts.

In your pre_get_posts filters you don't have to manually parse_query to actually apply the changes, so it shouldn't be required for changes to meta_query either.

This was odd to me. ​https://gist.github.com/markjaquith/681af58ce22d79c08c09

But moving it would be a breaking change. Maybe we should just have another hook that happens before parsing.

But moving it would be a breaking change.

I think parse_query_vars for meta_query already takes care of double parsing, in case somebody is doing it manually on pre_get_comments.

Maybe we should just have another hook that happens before parsing.

That could be a solution, but it would make the pre_get_ filters inconsistent.