Re: FOR PORTION OF silently ignored on views with DO INSTEAD rules

On Thu, Sep 3, 2026 at 7:38 PM Ewan Young <kdbase(dot)hack(at)gmail(dot)com> wrote:
>
> > On the other hand a DO INSTEAD NOTHING rule is allowed. Ewan's patch
> > also allows DO INSTEAD NOTHING. That makes sense to me. Here is a
> > revised patch adding it to Ewan's tests.
>
> One small thing: the new test cases use "do nothing", which the grammar
> treats as DO ALSO NOTHING (opt_instead defaults to ALSO), so those rules
> don't replace the query and FOR PORTION OF keeps working through the
> auto-updatable path. An actual unqualified "do instead nothing" rule
> sets the instead flag in fireRules(), so the patch rejects it with the
> same error, for both UPDATE and DELETE. I think that is fine and
> consistent with the ON CONFLICT precedent you mention, but the test
> comment and the last paragraph of the commit message say the opposite,
> so they should be adjusted one way or the other. (Also, the second
> "do nothing" rule says "on update" where "on delete" was intended.)

Oh, good catch! I've updated the test. Even with "DO INSTEAD NOTHING",
ON CONFLICT does allow the rule. I think this is important, since DO
INSTEAD NOTHING has a somewhat special role as a fallback when there
are other conditional rules.[0] So I'd like to make FOR PORTION OF
work the same way. Making the fixed test pass required a very small
code change. Here is a v3 with those edits.

[0] https://www.postgresql.org/docs/current/sql-createrule.html

Yours,

--
Paul ~{:-)
pj(at)illuminatedcomputing(dot)com