Horton

Re: printf %s with NULL pointer (was Re: BUG #17098: Assert failed on composing an error message when adding a type to an extension being dropped)

Ranier Vilela <ranier.vf@gmail.com>

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From: Ranier Vilela <ranier.vf@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Laurenz Albe <laurenz.albe@cybertec.at>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-07-13T18:38:02Z
Lists: pgsql-bugs, pgsql-hackers 
Em ter., 13 de jul. de 2021 às 15:26, Tom Lane <tgl@sss.pgh.pa.us> escreveu:

> Ranier Vilela <ranier.vf@gmail.com> writes:
> > Em ter., 13 de jul. de 2021 às 11:29, Tom Lane <tgl@sss.pgh.pa.us>
> escreveu:
> >> I think you're missing my main point, which is that it seems certain
> that
> >> there are corner cases that do this *now*.  I'm proposing that we
> redefine
> >> this as not being a crash case, full stop.
>
> > I agree with Laurenz Albe, that on Debug builds, *printf with NULL, must
> > crash.
>
> Did you see my followup?

I am trying.


>   The vast majority of live systems do not do
> that, so we are accomplishing nothing of value by insisting it's a
> crash-worthy bug.
>
I agreed.


> I flat out don't agree that "crash on debug builds but it's okay on
> production" is a useful way to define this.  I spend way too much
> time already on bug reports that only manifest with asserts enabled.
>
I understand.
Bug reports will decrease, because of that, people will lose interest and
motivation to report,
because (null), it doesn't seem like a serious error and my server didn't
crash.

It's a tricky tradeoff.

regards,
Ranier Vilela

Commits

  1. Make printf("%s", NULL) print "(null)" instead of crashing.

  2. Lock the extension during ALTER EXTENSION ADD/DROP.

  3. Add an assertion that we don't pass NULL to snprintf("%s").

  4. Fix broken logic for reporting PL/Python function names in errcontext.