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

jian he <jian(dot)universality(at)gmail(dot)com> writes:
> just found out the"elog(INFO, "should not reached here");" part never reached.

You didn't check any of the cases we were discussing I guess?
(That is, places in gram.y that throw an error without a
parser_errposition call.)

Note that even if we fix all of those and keep them fixed, we still
couldn't assume the case is unreachable, because gram.y isn't
self-contained. For instance, if we hit out-of-memory during raw
parsing, the OOM error out of mcxt.c isn't going to provide a syntax
error position. I'm not too concerned about doing better than what
the patch does now (i.e. nothing) in such edge cases, but we can't
do worse.

> i guess, we don't need performance in script_error_callback,
> but in script_error_callback arrange code seperate syntax error(raw
> parser) and other error seems good.
> please check the attached minor refactor.

I do not think that's an improvement. It's more complicated and
less readable, and I don't see why we need to squeeze more
performance out of this error-reporting path that should never
be taken in production.

regards, tom lane