Incorrect top-level threading in non-singular Atom comment feed

[mdgl]

In non-singular Atom comment feeds (i.e. those for archives, search and home), incorrect threading information is provided for top-level comments (i.e. comments that refer directly to a post/page, not ones made in reply to another comment).

Instead of the correct and specific parent post in each case, the threading information for such comments always refers to the same single (random) post from the feed.

To reproduce the bug, create several new top-level comments on distinct posts and then view the generated XML for the Atom comments feed on your blog home page, inspecting the "<thr:in-reply-to>" elements as defined by RFC 4685.

The erroneous code seems to be in file "feed-atom-comments.php" at line 76 (at WP 3.0.1), where the parent link is output using "the_guid()" and "the_permalink_rss()". I think these functions need to refer to the correct and specific parent post using the variable "$comment_post". See the related code outputting the "<title>" element earlier in this file.

Also in this file at line 46 is what appears to be a redundant call to "get_post_custom" where the output is simply thrown away [this is also in file "feed-rss-comments.php" line 66]. Perhaps this was part of some earlier attempt to get the appropriate global variables updated, but in any case it doesn't work and seems completely unnecessary!

I'm surprised this threading issue hasn't been noticed before. It looks like nobody uses this stuff :-)

[solarissmoke]

Ensure post global is set in feed-atom-comments.php

[solarissmoke]

Wow, I'm surprised too! I guess most people stick with RSS.

[markjaquith]

Nice catch.

[solarissmoke]

Updated patch - no need to pass by reference in PHP5

[solarissmoke]

This is a really simple fix for an issue that has been open for a year, would be nice to see it in 3.3?

[SergeyBiryukov]

14908.2.patch​ also removes redundant calls to get_post_custom().

[westi]

In [18716]:

Set up the post global variable in the comment feed loops so that any calls to post related template tags work correctly.
Ensures that atom feeds show threading for top-level comments correctly.
Fixes #14908 props solarissmoke and SergeyBiryukov.