On Fri, Sep 12, 2025 at 4:07 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Dominique Devienne <ddevienne@gmail.com> writes:
> >> This DOES look like a bug, no? I've done regexes for a long time,
> >> and these two forms should be equivalent IMHO. --DD
>
> Yeah, I agree it's busted. You can use EXPLAIN VERBOSE to see the
> translated-to-POSIX pattern, and it's wrong.
Thanks for confirming Tom.
And teaching me about that EXPLAIN VERBOSE trick.
I've worked-around that regression in our code, going to (x|y) instead.
What's weird is that those are still followed by _ and %,
just like [xy], so it's as-if seeing [\d\w], it stops converting
the pattern... Weird.
This misadventure kinda tells me I should maybe give up
on SIMILAR TO and just use ~, to bypass that conversion-to-POSIX...
--DD