Re: ALTER COLUMN TYPE vs. domain constraints

On Fri, Oct 27, 2017 at 11:15 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> We could consider back-patching the attached to cover this, but
> I'm not entirely sure it's worth the trouble, because I haven't
> thought of any non-silly use-cases in the absence of domains
> over composite.  Comments?

There are no real complaints about the current behavior, aren't there?
So only patching HEAD seems enough to me.

+comment on constraint c1 on domain dcomptype is 'random commentary';
[...]
+alter type comptype alter attribute r type bigint;
You have added a comment on the constraint to make sure that it
remains up on basically this ALTER TYPE. Querying pg_obj_description
would make sure that the comment on the constraint is still here.

+static void
+RebuildDomainConstraintComment(AlteredTableInfo *tab, int pass, Oid objid,
+                              List *domname, char *conname)
There is much duplication with RebuildConstraintComment. Why not
grouping both under say RebuildObjectComment()? I would think about
having cmd->objtype and cmd->object passed as arguments, and then
remove rel and domname from the existing arguments.

[nit]
            foreach(lcmd, subcmds)
-               ATExecCmd(wqueue, tab, rel, (AlterTableCmd *)
lfirst(lcmd), lockmode);
+               ATExecCmd(wqueue, tab, rel,
+                         castNode(AlterTableCmd, lfirst(lcmd)),
+                         lockmode);
This does not really belong to this patch.. No objections to group things.
[/nit]
-- 
Michael