Re: API stability [was: pgsql: Fix possible recovery trouble if TRUNCATE overlaps a checkpoint.]

On Tue, Apr 5, 2022 at 10:32 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
> > On Tue, Apr 5, 2022 at 10:17 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >> Renaming it would constitute an API break, which is if anything worse
> >> than an ABI break.
>
> > I don't think so, because an API break will cause a compilation
> > failure, which an extension author can easily fix.
>
> My point is that we want that to happen in HEAD, but it's not okay
> for it to happen in a minor release of a stable branch.

I understand, but I am not sure that I agree. I think that if an
extension stops compiling against a back-branch, someone will notice
the next time they try to compile it and will fix it. Maybe that's not
amazing, but I don't think it's a huge deal either. On the other hand,
if existing builds that someone has already shipped stop working with
a new server release, that's a much larger issue. The extension
packager can't go back and retroactively add a dependency on the
server version to the already-shipped package. A new package can be
shipped and specify a minimum minor version with which it will work,
but an old package is what it is.

-- 
Robert Haas
EDB: http://www.enterprisedb.com