On Mon, Apr 10, 2023 at 09:46:59AM -0400, Tom Lane wrote:
> It's still good to know about it for next time. The issue I guess is
> that LIKE with no options propagates column attnotnull bits, but not
> constraints, so we now have an inconsistency: t2.c has attnotnull set
> but there is nothing in pg_constraint to justify it. It seems to me
> we're going to have to think about what we want to happen in this
> case. In a green field we'd probably not propagate NOT NULL unless
> told to copy constraints ... but is it okay to break functional
> compatibility with the old behavior?
I am not sure about that, TBH, though I would tend to not break
compatibility just for the sake of breaking it. Anyway, shouldn't we
have a test that does a DROP NOT NULL after a LIKE copies it? At
least, we'll be able to track that.
--
Michael