On Sun, May 28, 2023 at 6:48 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> This seems pretty cool. I agree that we're in dire need of some
> tool of this sort for checking back-branch patches. I wonder
> though if it'll have false-positive problems. Have you tried it
> on live rather than mocked-up cases, for instance 13.0 vs 13.11?
I tried comparing REL_11_0 to REL_11_20. Attached is the report for that.
I don't have time to study this in detail today, but the report seems
to have a plausible variety of issues. I noticed that it warns about
the breaking signature change to _bt_pagedel(). This is the
theoretical ABI break that I mentioned in the commit message of commit
b0229f26. This is arguably a false positive, since the tool doesn't
understand my reasoning about why it's okay in this particular
instance (namely "any extension that called that function was already
severely broken"). Obviously the tool couldn't possibly be expected to
know better in these kinds of situations, though, so whether or not it
counts as a false positive is just semantics.
Fortunately, there aren't very many issues in the report. Certainly
not enough for false positives (however you define them) to be of
great concern. This is nearly 5 years worth of ABI issues.
--
Peter Geoghegan