Re: Can't find not null constraint, but \d+ shows that

On 2024-Apr-13, jian he wrote:

> I wonder is there any incompatibility issue, or do we need to say something
> about the new behavior when dropping a key column?

Umm, yeah, maybe we should document it in ALTER TABLE DROP PRIMARY KEY
and in the release notes to note the different behavior.

> only minor cosmetic issue:
> + if (unconstrained_cols)
> i would like change it to
> + if (unconstrained_cols != NIL)
>
> + foreach(lc, unconstrained_cols)
> we can change to
> + foreach_int(attnum, unconstrained_cols)
> per commit
> https://git.postgresql.org/cgit/postgresql.git/commit/?id=14dd0f27d7cd56ffae9ecdbe324965073d01a9ff

Ah, yeah.  I did that, rewrote some comments and refined the tests a
little bit to ensure the pg_upgrade behavior is sane.  I intend to get
this pushed tomorrow, if nothing ugly comes up.

CI run: https://cirrus-ci.com/build/5471117953990656