form '^(foo)$'. Before, these could never be optimized into indexscans. The recent changes to make psql and pg_dump generate such patterns (for \d commands and -t and related switches, respectively) therefore represented a big performance hit for people with large pg_class catalogs, as seen in recent gripe from Erik Jones. While at it, be more paranoid about case-sensitivity checking in multibyte encodings, and fix some other corner cases in which a regex might be interpreted too liberally.
ps_TupFromTlist in plan nodes that make use of it. This was being done correctly in join nodes and Result nodes but not in any relation-scan nodes. Bug would lead to bogus results if a set-returning function appeared in the targetlist of a subquery that could be rescanned after partial execution, for example a subquery within EXISTS(). Bug has been around forever :-( ... surprising it wasn't reported before.
immutable, because their results depend on lc_numeric; this is a longstanding oversight. We cannot force initdb for this in the back branches, but we can at least provide correct catalog entries for future installations.
cause any serious harm in normal cases, but if you have gcc buffer overrun checking turned on, that will notice. Found by Jack Orenstein. Problem was already fixed in CVS HEAD.