On 12.12.25 10:53, Michael Paquier wrote:
On Thu, Dec 11, 2025 at 11:43:27AM -0500, Tom Lane wrote:
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.
Yeah, I'd prefer something where we keep track of the type, with the
extra layer that enforces a cast to the type of the variable like
palloc_object/array macros. The latter style of specifying a variable
pointer within the sizeof is more error-prone long-term, so it's not
something I think we should encourage.
The original proposal that led to palloc_object() etc.[0] contained a
function palloc_ptrtype() that you would use like
foo = palloc_ptrtype(foo)
but people didn't like that for all these reasons.
[0]:
https://www.postgresql.org/message-id/flat/[email protected]
