Re: pg_dump does not dump domain not-null constraint's comments

On 2025-Jul-18, jian he wrote:

> one minor issue in getDomainConstraints:
>
> for (int i = 0, j = 0; i < ntups; i++)
> {
> char contype = (PQgetvalue(res, i, i_contype))[0];
> ....
> constraint->contype = *(PQgetvalue(res, i, i_contype));
> }
>
> for the same code simplicity,
> ``constraint->contype = *(PQgetvalue(res, i, i_contype));``
> can change to
> `` constraint->contype = contype; ``
> ?
> other than that, looks good to me.

Thanks, changed it that way.

I noticed some other issues however. First, you had removed the contype
comparisons in repairDependencyLoop; I put them back several versions of
the patch ago, but I had mistakenly made them reference the wrong array
item -- in all three places. Doh.

Second, the name comparisons to determine whether to list the constraint
name in the "CREATE DOMAIN .. NOT NULL" syntax was wrong: it was using
fmtId() around the constraint name, but of course that would have never
worked, because we're comparing to the original string, not a quoted
name. So if you had a domain called, say
CREATE DOMAIN "my domain" AS int NOT NULL;

then pg_dump would have said
CREATE DOMAIN "my domain" AS int CONSTRAINT "my domain_not_null" NOT NULL;

even though listing the name is unnecessary. This wouldn't have made
the dump fail, so it's borderline; but it would be /slightly/ ugly.

Lastly, I made dumpDomain print unadorned "NOT NULL" if a pg_constraint
row for the constraint is not found and yet we observe typnotnull set.
This can be considered catalog corruption (the row should be there), but
I think this is better than having pg_dump just crash if that row is not
there.

--
Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/
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