On Sat, Nov 7, 2015 at 2:32 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> What I'm wondering about is whether to back-patch this. It's possible
> that people have written patterns like this and not realized that they
> aren't doing quite what's expected. Getting a failure instead might not
> be desirable in a minor release. On the other hand, wrong answers are
> wrong answers.
I would say wrong answers are wrong answers. It's hard to believe
there are many people doing this but if they are they're certainly
expecting the look-ahead to actually test that it's looking at the
same thing as the capturing parens. It might even be something
security-critical like parsing an connection string or something like
that. I can't see it's doing people any favours to let their code
continue doing something unexpected to avoid new errors.
--
greg