Re: BUG #15046: non-greedy ignored

On Friday, February 2, 2018, PG Bug reporting form <noreply(at)postgresql(dot)org>
wrote:

> The following bug has been logged on the website:
>
> Bug reference: 15046
> Logged by: Bob Gailer
> Email address: bgailer(at)gmail(dot)com
> PostgreSQL version: 10.1
> Operating system: windows 10
> Description:
>
> I start psql; enter:
>
> postgres=# select regexp_replace('a(d)s(e)f', '\(.*?\)', '', 'g');
> regexp_replace
> ----------------
> asf
> (1 row)
>
> Works as expected. Then I add |q to the pattern, and the .*? becomes
> greedy!
>
> postgres=# select regexp_replace('a(d)s(e)f', '\(.*?\)|q', '', 'g');
> regexp_replace
> ----------------
> af
> (1 row)
>
>
This seems to be explained by the final greediness rule:

https://www.postgresql.org/docs/10/static/functions-matching.html#POSIX-MATCHING-RULES

-

An RE consisting of two or more branches connected by the | operator is
always greedy.

David J.