Re: Use IsA() macro instead of nodeTag comparison

Hi,

On Fri, Jan 09, 2026 at 08:56:00AM +0800, Chao Li wrote:
> 
> 
> > On Jan 9, 2026, at 08:32, Fujii Masao <masao.fujii@gmail.com> wrote:
> > 
> > On Fri, Jan 9, 2026 at 2:11 AM Heikki Linnakangas <hlinnaka@iki.fi> wrote:
> >> 
> >> On 08/01/2026 15:10, Kirill Reshke wrote:
> >>> On Thu, 8 Jan 2026 at 17:31, Shinya Kato <shinya11.kato@gmail.com> wrote:
> >>>> In copy.c, nodeTag was being compared directly, so I replaced it with
> >>>> the IsA() predicate macro for consistency.
> >>> 
> >>> Oops. Looks like oversight in 6c8f670. This is indeed case where we
> >>> should use IsA()
> >>> 
> >>>> I verified that there are no other direct comparisons left by running
> >>>> the following command:
> >>>> $ git grep "nodeTag(.*) =="
> >>> 
> >>> Yep, look like this is the only case in copy.c
> > 
> > I found a similar issue in define.c. Should we fix it there as well?
> > 
> > diff --git a/src/backend/commands/define.c b/src/backend/commands/define.c
> > index 63601a2c0b4..8313431397f 100644
> > --- a/src/backend/commands/define.c
> > +++ b/src/backend/commands/define.c
> > @@ -349,7 +349,7 @@ defGetStringList(DefElem *def)
> >                                (errcode(ERRCODE_SYNTAX_ERROR),
> >                                 errmsg("%s requires a parameter",
> >                                                def->defname)));
> > -       if (nodeTag(def->arg) != T_List)
> > +       if (!IsA(def->arg, List))
> >                elog(ERROR, "unrecognized node type: %d", (int)
> > nodeTag(def->arg));
> > 
> >        foreach(cell, (List *) def->arg)
> > 
> > Regards,
> > 
> > -- 
> > Fujii Masao
> 
> Yep, I did a search with `nodeTag\(.*\)\s+(?:!=|==).*`, and this is the only finding.

Yeah, I was going to submit the exact same patch detected with the help of
[1]. That's the only remaining case.

[1]: https://github.com/bdrouvot/coccinelle_on_pg/blob/main/misc/nodetag.cocci

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com