On Tue, Jun 11, 2024 at 10:55 AM David E. Wheeler <david@justatheory.com> wrote:
> Right, it’s just that extension authors could use some notification that such a change is coming so they can update
theircode, if necessary.
In general our strategy around ABI breaks is to avoid them whenever
possible. We also make the most conservative assumptions about what a
true ABI break is -- strictly speaking we can never be fully sure
about the impact of a theoretical/mechanical ABI break (we can only
make well educated guesses). My sense is that we're approaching having
the fewest possible real ABI breaks already -- we're already doing the
best we can. That doesn't seem like a useful area to focus on.
As an example, my bugfix commit 714780dc was apparently discussed by
Yurii Rashkovskii during his pgConf.dev talk. I was (and still am)
approaching 100% certainty that that wasn't a true ABI break.
Documenting this somewhere seems rather unappealing. Strictly speaking
I'm not 100% certain that this is a non-issue, but who benefits from
hearing my hand-wavy characterisation of why I believe it's a
non-issue? You might as well just look at an ABI change report
yourself.
Approximately 0% of all extensions actually use the struct in
question, and so obviously aren't affected. If anybody is using the
struct then it's merely very very likely that they aren't affected.
But why trust me here? After all, I can't even imagine why anybody
would want to use the struct in question. My hand-wavy speculation
about what it would look like if I was wrong about that is inherently
suspect, and probably just useless. Is it not?
That having been said, it would be useful if there was a community web
resource for this -- something akin to coverage.postgresql.org, but
with differential ABI breakage reports. You can see an example report
here:
https://postgr.es/m/CAH2-Wzm-W6hSn71sUkz0Rem=qDEU7TnFmc7_jG2DjrLFef_WKQ@mail.gmail.com
Theoretically anybody can do this themselves. In practice they don't.
So something as simple as providing automated reports about ABI
changes might well move the needle here.
--
Peter Geoghegan