Re: Assignment of valid collation for SET operations on queries with UNKNOWN types.

Rahila Syed <rahilasyed90(at)gmail(dot)com> writes:
> CASE 2:
> postgres=# create view v as select 'abc' a;
> 2016-11-16 15:28:48 IST WARNING: column "a" has type "unknown"
> 2016-11-16 15:28:48 IST DETAIL: Proceeding with relation creation anyway.
> WARNING: column "a" has type "unknown"
> DETAIL: Proceeding with relation creation anyway.
> CREATE VIEW

We really ought to make that a hard error. And ideally fix things so
that the type of the view column will be resolved as text, so that you
don't hit this condition in the first place; but there is no good that
comes out of allowing a view to be created like this.

> Attached WIP patch does that. Kindly let me know your opinion.

This is a seriously ugly kluge that's attacking the symptom not the
problem. Or really, a symptom not the problem. There are lots of
other symptoms, for instance

regression=# select * from v order by 1;
ERROR: failed to find conversion function from unknown to text

regards, tom lane