comments_link filter can not be run on comments_popup_link if post has no comments.

[joedolson]

The filter 'comments_link' is run in the function comments_link(), called by comments_popup_link(). However, if a post has no comments, it doesn't call comments_link(); it calls get_permalink() and appends hashtag fragment (basically, recreating what comments_link() does.)

This means that you can't filter the comments link separately from the permalink if a post has no comments.

Additionally, comments_link() is a deprecated function, so core shouldn't be using it.

Patch uses get_comments_link regardless of number of comments & removes comments_link from function.

[joedolson]

Use get_comments_link() instead of get_permalink/comments_link

[SergeyBiryukov]

Additionally, comments_link() is a deprecated function, so core shouldn't be using it.

comments_link()​ has two deprecated arguments, but the function itself is not deprecated.

[joedolson]

Ah - moving too quickly; misread that. Regardless, the rest of the statement stands.

[helen]

Been this way since [6372].

[SergeyBiryukov]

comments_link() has an additional benefit of esc_url() after the filter, we should keep using it here.

Note that get_permalink() . '#respond' is a direct link to the comment form, while comments_link() is a link to the comments block. There is no difference in default themes with no comments, but there might be a difference in other themes.

Perhaps we could add a new filter, get_respond_link.

[joedolson]

I think that a new filter would definitely work, too - I'll add a patch for that, instead. Practically speaking, the important thing is to be able to filter the comment link whether the post has comments or not; using get_respond_link as a filter would fulfill that.

For consistency, I think that the filter should probably be respond_link, since it's run in a printing function.

[joedolson]

Add respond_link filter to comments_link()

[wonderboymusic]

In 34216:

Apply the new 'respond_link' filter in comments_popup_link() if $number is 0 before outputting the URL.

Props joedolson.
Fixes #29454.