Re: Underscore in positional parameters?

On Tue, 14 May 2024 at 07:43, Michael Paquier <michael@paquier.xyz> wrote:
>
> On Tue, May 14, 2024 at 05:18:24AM +0200, Erik Wienhold wrote:
> > Parameter $1_2 is taken as $1 because in rule {param} in scan.l we get
> > the parameter number with atol which stops at the underscore.  That's a
> > regression in faff8f8e47f.  Before that commit, $1_2 resulted in
> > "ERROR: trailing junk after parameter".
>
> Indeed, the behavior of HEAD is confusing.  "1_2" means 12 as a
> constant in a query, not 1, but HEAD implies 1 in the context of
> PREPARE here.
>
> > I can't tell which fix is the way to go: (1) accept underscores without
> > using atol, or (2) just forbid underscores.  Any ideas?
>
> Does the SQL specification tell anything about the way parameters
> should be marked?  Not everything out there uses dollar-marked
> parameters, so I guess that the answer to my question is no.  My take
> is all these cases should be rejected for params, only apply to
> numeric and integer constants in the queries.
>
> Adding Dean in CC as the committer of faff8f8e47f, Peter E for the SQL
> specification part, and an open item.

I'm sure that this wasn't intentional -- I think we just failed to
notice that "param" also uses "decinteger" in the scanner. Taking a
quick look, there don't appear to be any other uses of "decinteger",
so at least it only affects params.

Unless the spec explicitly says otherwise, I agree that we should
reject this, as we used to do, and add a comment saying that it's
intentionally not supported. I can't believe it would ever be useful,
and the current behaviour is clearly broken.

I've moved this to "Older bugs affecting stable branches", since it
came in with v16.

Regards,
Dean