Comments: Exclude notes from get_lastcommentmodified().

[dhrupo]

Trac ticket: https://core.trac.wordpress.org/ticket/65657

Summary

get_lastcommentmodified() returns the date of the most recent approved comment, and WP::send_headers() uses it (max'd with get_lastpostmodified()) to build the Last-Modified and ETag headers for the comments feed.

Its three queries did not exclude the internal note comment type:

SELECT comment_date_gmt FROM wp_comments WHERE comment_approved = '1' ORDER BY comment_date_gmt DESC LIMIT 1

Notes are stored as approved comments (comment_type = 'note'), so adding or resolving a note makes it the most recent comment. The public comments feed's Last-Modified/ETag then change, even though the feed body already excludes notes (#64145 / #65613) and did not change.

Consequences:

• Conditional GET (304 Not Modified) caching of the comments feed is defeated whenever notes are used — clients and CDNs re-fetch an identical feed.
• The public Last-Modified header exposes the timing of internal editorial notes.

Reproduction

On a site using Notes:

curl -I '/?feed=comments-rss2'   # note Last-Modified + ETag
# add an internal note to any post
curl -I '/?feed=comments-rss2'   # Last-Modified + ETag have changed; feed body is unchanged

Verified live: adding one note moved Last-Modified from Fri, 01 Jan 2027 10:00:00 GMT to Sat, 02 Jan 2027 10:00:00 GMT and changed the ETag. See the before/after screenshots on the Trac ticket.

Fix

Add AND comment_type != 'note' to the three get_lastcommentmodified() queries, matching the exclusion already used by wp_update_comment_count_now() and the comment feed queries.

Testing

Added test_notes_are_excluded to Tests_Comment_GetLastCommentModified.

• Before the fix, it fails: Failed asserting that <note timestamp> is identical to <regular-comment timestamp>.
• After the fix, it passes.

Full comment group is green:

./vendor/bin/phpunit --group comment
OK (583 tests, 1428 assertions)

Use of AI Tools

AI assistance: Yes
Tool(s): Claude Code
Model(s): Claude Opus 4.8
Used for: Auditing the notes-exclusion surfaces, reproducing the feed-header change, implementing the fix, and writing the regression test. All changes were reviewed by me.

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