Reporting hba lines

When debugging strange and complex pg_hba lines, it can often be quite
useful to know which line is matching a particular connection that
failed for some reason. Because more often than not, it's actually not
using the line in pg_hba.conf that's expected.

The easiest way to do this is to emit an errdetail for the login
failure, per this patch.

Question is - is that leaking information to the client that we
shouldn't be leaking?

And if it is, what would be the preferred way to deal with it? We
could put that as a detail to basically every single error message
coming out of the auth system, but that seems like a bad idea. Or we
could make a separate ereport(LOG) before send it to the client,
perhaps?

Thoughts?

--
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/