Re: Better error reporting from extension scripts (Was: Extend ALTER OPERATOR)

po 14. 10. 2024 v 5:38 odesílatel jian he <jian(dot)universality(at)gmail(dot)com>
napsal:

> On Mon, Oct 14, 2024 at 1:13 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >
> > Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> writes:
> > > so 12. 10. 2024 v 9:33 odesílatel jian he <jian(dot)universality(at)gmail(dot)com
> >
> > > napsal:
> > >> + /*
> > >> + * If we have a location (which, as said above, we really always
> should)
> > >> + * then report a line number to aid in localizing problems in big
> scripts.
> > >> + */
> > >> + if (location >= 0)
> > >> so this part will always be true?
> >
> > > yes, after CleanQuerytext the location should not be -1 ever
> >
> > Right, but we might not have entered either of those previous
> > if-blocks.
>
>
> in src/backend/parser/gram.y
> your makeRawStmt changes (v4) seem to guarantee that
> RawStmt->stmt_location >= 0.
> other places {DefineView,DoCopy,PrepareQuery} use makeNode(RawStmt),
> In these cases, I am not so sure RawStmt->stmt_location >=0 is always
> true.
>
> in execute_sql_string
>
> raw_parsetree_list = pg_parse_query(sql);
> dest = CreateDestReceiver(DestNone);
> foreach(lc1, raw_parsetree_list)
> {
> RawStmt *parsetree = lfirst_node(RawStmt, lc1);
> MemoryContext per_parsetree_context,
> oldcontext;
> List *stmt_list;
> ListCell *lc2;
> callback_arg.stmt_location = parsetree->stmt_location;
> callback_arg.stmt_len = parsetree->stmt_len;
> per_parsetree_context =
> AllocSetContextCreate(CurrentMemoryContext,
> "execute_sql_string per-statement
> context",
> ALLOCSET_DEFAULT_SIZES);
> oldcontext = MemoryContextSwitchTo(per_parsetree_context);
> CommandCounterIncrement();
> stmt_list = pg_analyze_and_rewrite_fixedparams(parsetree,
> sql,
> NULL,
> 0,
> NULL);
>
> Based on the above code, we do
> `callback_arg.stmt_location = parsetree->stmt_location;`
> pg_parse_query(sql) doesn't use script_error_callback.
>
> So if we are in script_error_callback
> `int location = callback_arg->stmt_location;`
> location >= 0 will be always true?
>
>
>
> > The question here is whether the raw parser (gram.y)
> > ever throws an error that doesn't include a cursor position. IMO it
> > shouldn't, but a quick look through gram.y finds a few ereports that
> > lack parser_errposition. We could go fix those, and probably should,
> > but imagining that none will ever be introduced again seems like
> > folly.
> >
>
> I don't know how to add the error position inside the function
> insertSelectOptions.
> maybe we can add
> `parser_errposition(exprLocation(limitClause->limitCount))));`
> but limitCount position is a nearby position.
> I am also not sure about func mergeTableFuncParameters.
>
>
> for other places in gram.y, I've added error positions for ereport
> that lack it , please check the attached.
>

I think this can be a separate commitfest issue.

Regards

Pavel