Subject: pgsql: pg_unicode_fast: fix final sigma logic.

From: Jeff Davis <[email-masked]>
Date: Tue, 07 Jul 2026 21:54:02 +0000

pg_unicode_fast: fix final sigma logic.

If the string is preceded only by Case Ignorable characters, don't
consider it to be a final sigma.

In the process, refactor so that the preceding and following
characters are found first, and then the rule is applied, to improve
clarity.

Discussion: https://postgr.es/m/[email-masked]
Backpatch-through: 18

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/36869368989ce37d85c08c33258eb01ae96e2375

Modified Files
--------------
src/common/unicode_case.c                  | 88 ++++++++++++++----------------
src/test/regress/expected/collate.utf8.out |  6 ++
src/test/regress/sql/collate.utf8.sql      |  1 +
3 files changed, 47 insertions(+), 48 deletions(-)