Re: CAST(... ON DEFAULT) - WIP build on top of Error-Safe User Functions

On Fri, Nov 21, 2025 at 2:11 PM jian he <jian(dot)universality(at)gmail(dot)com> wrote:
>
> On Mon, Nov 17, 2025 at 9:43 PM Amul Sul <sulamul(at)gmail(dot)com> wrote:
> >
> > 10-0004:
> >
> > +/* error safe version of textToQualifiedNameList */
> > +List *
> > +textToQualifiedNameListSafe(text *textval, Node *escontext)
> >
> > If I am not mistaken, it looks like an exact copy of
> > textToQualifiedNameList(). I think you can simply keep only
> > textToQualifiedNameListSafe() and call that from
> > textToQualifiedNameList() with a NULL value for escontext. This way,
> > all errsave() or ereturn() calls will behave like ereport().
> >
> > The same logic applies to RangeVarGetRelidExtendedSafe() and
> > makeRangeVarFromNameListSafe. These can be called from
> > RangeVarGetRelidExtended() and makeRangeVarFromNameList(),
> > respectively.
> > --
> >
>
> hi.
>
> List *
> textToQualifiedNameList(text *textval)
> {
> List *namelist;
> rawname = text_to_cstring(textval);
> if (!SplitIdentifierString(rawname, '.', &namelist))
> ereport(ERROR,
> (errcode(ERRCODE_INVALID_NAME),
> errmsg("invalid name syntax")));
> }
>
> I don’t see any way to pass the escontext (ErrorSaveContext) without changing
> the textToQualifiedNameList function signature.
>
> There are around 30 occurrences of textToQualifiedNameList.
> changing the function textToQualifiedNameList signature is invasive,
> so I tend to avoid it.
> I think it's easier to just duplicate textToQualifiedNameList
> than changing the function textToQualifiedNameList signature.
>
> Am I missing something?
>

The change I was suggesting will be as below:

--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -2684,6 +2684,13 @@ name_text(PG_FUNCTION_ARGS)
*/
List *
textToQualifiedNameList(text *textval)
+{
+ textToQualifiedNameListSafe(textval, NULL);
+}
+
+/* error safe version of textToQualifiedNameList */
+List *
+textToQualifiedNameListSafe(text *textval, Node *escontext)
{
char *rawname;
List *result = NIL;

We must try to avoid duplication whenever possible, as any bug fixes
or enhancements would need to be copied to multiple places, which is
often overlooked.

Regards,
Amul