Fix improper xreflabels created for v18 release notes

On Thu, Jan 1, 2026 at 11:55:27AM -0500, Robert Treat wrote:

Looking at https://www.postgresql.org/docs/current/xplang.html during
a near by discussion, I was bothered that plpython was not formatting
the same way as the other PL's listed on that page, so I went
spelunking to see what had happened.

Huh, I didn't notice that, but now that I think if it, it makes sense. I
forgot that adding xreflabel can change references to it ---
doc/src/sgml/README.link clearly states this:

<xref>
use to get chapter/section number from the title of the
--> target link, or xreflabel if defined at the target, or
refentrytitle if target is a refentry; has no close tag
http://www.oasis-open.org/docbook/documentation/reference/html/xref.html

It turns out that some xref labels were added during this commit
(https://github.com/postgres/postgres/commit/d8aa21b74ff4e3d767c3344484c3cb22b9f0ec0d)
in order to make the links more readable in the v18 release notes.

However, based on the discussion here:
/messages/by-id/20200611223836.GA2507@momjian.us,
the correct way to style links from the release notes is through the
<link> tag, not by adding xrefs, which can have unintended
side-effects in other places (like in the initial doc link above).

Yep.

This is a little tricky to fix as it needs to happen across 2
different branches, but I believe the right way to fix this involves 2
parts. First, apply patch 01, which converts the xrefs in the v18
release notes to link tags, against REL_18_STABLE, since those release
notes don't exist on master.

Applied.

Second, either revert the original commit linked above, or apply the
patch 02 which just undoes those changes. Note, I created the patch
against master, but I think it should be applied there and back
patched to 18 stable.

I applied your patch two to both branches.

Also note I did a quick scan to see if either the liboq or plpython
xreflabel situation existed elsewhere but I only turned up one usage,
at https://www.postgresql.org/docs/current/triggers.html, which is
also corrected with these changes.

Yeah, I see some xreflabels for "sect1" links but none for "chapter",
except those two I just removed. Not sure what our future plans are in
this area, and I know there was a recent thread about this, but we
should remain consistent.

Thanks for the research, and I apologize for the mistake.

--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com

Do not let urgent matters crowd out time for investment in the future.