On 2016-12-08 18:03:04 -0500, Tom Lane wrote: > Andres Freund <and...@anarazel.de> writes: > > On 2016-12-08 17:38:38 -0500, Tom Lane wrote: > >> The habit of zero-initializing Datums has got exactly nothing to do with > >> V0 functions; it's about ensuring consistent results and avoiding > >> heisenbugs from use of uninitialized memory. I do not think we should > >> drop it. > > > Well, V0 functions don't have a real way to get information about NULL, > > and we allow non-strict V0 functions, so? > > Non-strict V0 functions are pretty fundamentally broken, although IIRC > there was some hack whereby they could see the isnull marker for their > first argument, which is why we didn't just disallow the case. There was > never any expectation that checking for value == 0 was an appropriate > coding method for detecting nulls, because it couldn't work for > pass-by-value data types.
Well, we have a bunch in our regression tests ;). And I'm not saying it's *good* that they rely on that, I think it's a reason to drop the whole V0 interface. (I also suspect there's a bunch in brin related to this) > Again, the point of initializing those values is not to support broken > tests for nullness. It's to ensure consistent behavior in case of > buggy attempts to use null values. Well, it also makes such attempts undetectable. I'm not really convinced that that's such an improvement. Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers