BUG #2144: Domain NOT NULL constraints ignored in rules

The following bug has been logged online:

Bug reference: 2144
Logged by: John Supplee
Email address: john(at)supplee(dot)com
PostgreSQL version: 8.1.1
Operating system: Fedore Core 4
Description: Domain NOT NULL constraints ignored in rules
Details:

I have a database with some views which have rules for insertion. One of
the views (view_a) inserts data into another view (view_b) with an insert
rule. The data inserted into view_b by view_a insert rule does not have
domain NOT NULL constraints enforced. That is, it is possible to insert a
NULL into a column whose domain forbids NULLs. NOT NULL constraints
attached directly to columns continue to forbid NULL data in the second view
(b).

If this requires more explanation let me know.

I have observed this behavior on versions 8.0.5 and 8.1.1