On Tue, Apr 9, 2024 at 6:18 PM Robert Haas <robertmhaas@gmail.com> wrote:
> On Thu, Apr 4, 2024 at 10:38 PM Michael Paquier <michael@paquier.xyz> wrote:
> > > It kind of looks like a libedit bug, but maybe we should dig more
> > > deeply. I felt itchy about 927332b95e77 removing '{' from the
> > > WORD_BREAKS set, and wondered exactly how that would change readline's
> > > behavior. But even if that somehow accounts for the extra backslash
> > > before '{', it's not clear how it could lead to '?' and '}' also
> > > getting backslashed.
> >
> > I don't have a clear idea, either. I also feel uneasy about
> > 927332b95e77 and its change of WORD_BREAKS, but this has the smell
> > of a bug from an outdated libedit version.
>
> I too felt uneasy about that commit, for the same reason. However,
> there is a justification for the change in the commit message which is
> not obviously wrong, namely that ":{?name} is the only psql syntax
> using the '{' sign". And in fact, SQL basically doesn't use '{' for
> anything, either. We do see { showing up inside of quoted strings, for
> arrays or JSON, but I would guess that the word-break characters
> aren't going to affect behavior within a quoted string. So it still
> seems like it should be OK? Another thing that makes me think that my
> unease may be unfounded is that the matching character '}' isn't in
> WORD_BREAKS either, and I would have thought that if we needed one
> we'd need both.
FWIW, the default value of rl_basic_word_break_characters [1] has '{'
but doesn't have '}'. The documentation says that this should "break
words for completion in Bash". But I failed to find an explanation
why this should be so for Bash. As you correctly get, my idea was
that our SQL isn't not heavily using '{' unlike Bash.
> But does anyone else have a more specific reason for thinking that
> this might be a problem?
I don't particularly object against reverting this commit, but I think
we should get to the bottom of this first. Otherwise there is no
warranty to not run into the same problem again.
Links.
1. https://tiswww.case.edu/php/chet/readline/readline.html#index-rl_005fbasic_005fword_005fbreak_005fcharacters
------
Regards,
Alexander Korotkov