Re: Fix and improve allocation formulas

Andres Freund <andres(at)anarazel(dot)de> writes:
> I tend to agree that what you propose is the better style, but I seriously
> doubt that

> a) changing over everything at once is worth the backpatch hazard and review
> pain
> b) that to judge whether we should do this a 277kB patch is useful
> c) that changing the existing code should be the first thing, if we want to
> make this the new style, we should first document the sizeof(*var) approach to
> be preferred.

And before that, you'd have to get consensus that sizeof(*var) *is*
the preferred style. I for one don't like it a bit. IMO what it
mostly accomplishes is to remove a cue as to what we are allocating.
I don't agree that it removes a chance for error, either. Sure,
if you write

foo = palloc(sizeof(typeA))

when foo is of type typeB*, you made a mistake --- but we know how
to get the compiler to warn about such mistakes, and indeed the
main point of the palloc_object() changes was to catch those.
However, suppose you write

foo = palloc(sizeof(*bar))

I claim that's about an equally credible typo, and there is
nothing that will detect it.

regards, tom lane