Re: BUG #8516: Calling VOLATILE from STABLE function

On Thu, Oct 10, 2013 at 04:10:35PM -0700, Dwayne Towell wrote:
> > According to the documentation, f() should be marked VOLATILE also, since
> > calling f() produces side effects. PostgreSQL does not give a warning (or
> > better yet, an error); I think it should.
>
> I think the answer is that function authors are required to prevent
> functions they mark as STABLE from calling VOLATILE functions.
>
> --
>
> I understand it's an error (at least usually), my question/issue is why does
> PostgreSQL NOT give at least a warning when a programmer (probably
> accidentally) calls a VOLATILE function in one that he has specifically
> tagged as STABLE? The compiler has all the information to notify the
> programmer of a mistake, but isn't. This violates a fundamental principle of
> software engineering--take every opportunity to prevent errors.

Well, we can't walk the function tree to know all called functions, and
those they call, so we don't even try.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + Everyone has their own god. +