BUG #5448: psql \set does not terminate if variable is referenced recursively

The following bug has been logged online:

Bug reference:      5448
Logged by:          Francis
Email address:      fmarkham@gmail.com
PostgreSQL version: 8.4.3
Operating system:   Ubuntu linux 10.04
Description:        psql \set does not terminate if variable is referenced
recursively
Details:

psql \set does not terminate if a variable is referenced recursively.  For
example, the following will hang the psql client in a nasty way:

db=# \set n 1
db=# \set n (:n + 1)