Re: BUG #17767: psql: tab-completion causes warnings when standard_conforming_strings = off

At Wed, 01 Feb 2023 15:01:34 -0500, Tom Lane <tgl@sss.pgh.pa.us> wrote in 
> I'm having a hard time getting excited about making such a change,
> TBH.  Why is it that you are running with
> standard_conforming_strings = off and escape_string_warning = on
> anyway?  If you haven't yet converted your apps to support
> standard-conforming strings, you probably aren't intent on
> doing so in the near future, so you might as well turn off
> escape_string_warning.  We last worried about silencing such
> warnings in our client programs more than a dozen years ago;
> I'm not sure we should still be worried in 2023.

I personally fine with the current behavior for the same reason as you
raised. We could enclose completion queries by "BEGIN; SET LOCAL
standard_... = on;" and "COMMIT;" in exec_query but I think you don't
like that (and me neither).

If we don't make that change, it might be good to add a note to the
documentation for standard_conforming_strings something like "Note
that setting this to off on a psql session can cause tab-completion
emit WARNING when command lines containing backslashes.", but even
that may be too noisy against the benefit..

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center