Re: ILIKE '%' never matches a non-ASCII byte in single-byte C-ctype databases

On Sun, 2026-10-18 at 15:30 +0000, Greg Burd wrote:
> Hi Hackers, Jeff,
>
> In v19, ILIKE in a database with a single-byte encoding and a C ctype
> never matches when '%' is followed by a byte >= 0x80:

Thank you for the report!

I attached a patch with a different approach though, which is to cast
the result of pg_ascii_tolower() so that GETCHAR() consistently returns
a 'char'. That addresses the real problem of commit 1e493158d3d, which
is that it unintentionally changed GETCHAR() from returning 'char' to
returning 'unsigned char' for MATCH_LOWER.

It passes the same test that you submitted, but I don't plan to commit
the tests with the change. We are missing coverage for non-UTF8
encodings, but if we're going to add tests for those, it should
probably be a whole suite rather than a one-off.

I plan to commit it very soon and backport to 19.

Regards,
Jeff Davis