Dropping columns with inheritance not working as documented

While investigating an issue someone reported in pg_partman (
https://github.com/keithf4/pg_partman/issues/61) came across something that
seems very inconsistent with Inheritance.

According to the documentation, dropping a column should be propagated down
to all children. This only seems to happen for columns that are added AFTER
a child table is inherited. There's no way to tell when a column was added
to an inheritance set, so this could be very confusing for someone down the
line that wasn't there when a table was set up.

Here is a gist showing this using the current version of pg_partman (1.8.6)
on PostgreSQL 9.4.2

https://gist.github.com/keithf4/a762144e46d0c4211d25

--
Keith Fiske
Database Administrator
OmniTI Computer Consulting, Inc.
http://www.keithf4.com