Re: BUG #8821: pg_trgm segfault with Turkish locale database

ufuk@paralaus.com writes:
> Given a database with encoding UTF-8, locale tr_TR.UTF-8, 'pg_trgm'
> extension enabled, and the following setup:

> CREATE TABLE car_makers (maker TEXT);
> INSERT INTO car_makers VALUES ('AUDI'), ('MINI');

> Run any one of the following commands:

> - SELECT maker <-> 'MAZDA' FROM car_makers;
> - SELECT similarity(maker, 'MAZDA') FROM car_makers;
> - SELECT show_trgm('III');

> As a result, it seems there is a problem with trigrams generation and/or
> comparison when the Turkish locale is being used.

It looks like generate_trgm() is not considering the possibility that
case-folding will make the string physically longer, so you get a buffer
overrun when any of these I-containing strings are converted to trigrams.
Will fix, thanks for the report!

            regards, tom lane