Re: BUG #19341: REPLACE() fails to match final character when using nondeterministic ICU collation

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Laurenz Albe <laurenz.albe@cybertec.at>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, adam.warland@infor.com, pgsql-bugs@lists.postgresql.org
Date: 2025-12-06T01:12:12Z
Lists: pgsql-bugs
Laurenz Albe <laurenz.albe@cybertec.at> writes:
> On Wed, 2025-12-03 at 10:12 -0500, Tom Lane wrote:
>> We do require callers to eliminate the empty-needle case, and given
>> that I think we could assume that match substrings must be at least
>> 1 byte long.  That assumption is what justifies the current API for
>> these functions, and perhaps we can also simplify this loop by
>> using it.

> The attached v5 patch simplifies the loop to a do-while loop, assuming
> that we cannot find a zero-length match.
> I have also updated the comments to no longer mention the possibility
> of an empty match, and for good measure I have added an Assert() that
> the needle cannot be empty.

LGTM.  Pushed with tiny cosmetic fixes (mostly, more work on the
comments).

			regards, tom lane