BUG #13911: pg_upgrade from 8.4 to 9.5 broken

The following bug has been logged on the website:

Bug reference: 13911
Logged by: Jerome Paul
Email address: jpaul(at)aconex(dot)com
PostgreSQL version: 9.5.0
Operating system: Ubuntu 14.04
Description:

Hi,

I've been attempting to run "pg_upgrade" to move data from Postgresql 8.4.22
to 9.5

The command I've been running is:

/usr/lib/postgresql/9.5/bin/pg_upgrade --old-datadir
'/etc/postgresql/8.4/main' --new-datadir '/etc/postgresql/9.5/main'
--old-bindir '/usr/lib/postgresql/8.4/bin' --new-bindir
'/usr/lib/postgresql/9.5/bin'

This results in the following error within "pg_upgrade_internal.log"

-----------------------------------------------------------------
pg_upgrade run on Thu Feb 4 13:30:13 2016
-----------------------------------------------------------------

Finding the real data directory for the old cluster Could not get
data directory using "/usr/lib/postgresql/8.4/bin/postgres" -D
"/etc/postgresql/8.4/main" -C data_directory: No such file or directory

It looks like the -C option was only added to the postgres command in 9.2.
The documentation for pg_upgrade states: "pg_upgrade supports upgrades from
8.4.X and later to the current major release of PostgreSQL, including
snapshot and alpha releases."

Is the upgrade script broken or the documentation incorrect?

sincerely
Jerome