Unexpected collation error in 9.1.1 - Mailing list pgsql-hackers

I tried adding a not-null column in one step and got a collation
error for a different column. Adding the column in several steps
works:


itd=> alter table livedata add column pricechanged timestamp not null default current_timestamp;
ERROR:  no collation was derived for column "whois_b" with collatable type citext
TIP:  Use the COLLATE clause to set the collation explicitly.

itd=> \d livedata                               Table "public.livedata"    Column    |            Type             |
           Modifiers
 
--------------+-----------------------------+----------------------------------------- accessid     | integer
         | not null sp_b         | double precision            | default 0 csh_b        | double precision            |
default0 sp_a         | double precision            | default 0 csh_a        | double precision            | default 0
asw_b       | double precision            | default 0 asw_a        | double precision            | default 0 amount
 | character varying(25)       | default ' '::character varying bench        | character varying(25)       | default
NULL::charactervarying updated_b    | date                        | updated_a    | date                        |
whois_b     | citext                      | default '          '::character varying whois_a      | citext
      | default '          '::character varying b_orig       | double precision            | default 0 a_orig       |
doubleprecision            | default 0 lcontrol     | integer                     | not null default 0 rcontrol     |
integer                    | not null default 0 hlcleared    | boolean                     | not null default false
yield_b     | double precision            | default 0 yield_a      | double precision            | default 0
 

itd=> alter table livedata add column pricechanged timestamp;
ALTER TABLE
itd=> alter table livedata alter column pricechanged set default current_timestamp;
ALTER TABLE
itd=> update livedata set pricechanged = default;
UPDATE 6000
itd=> alter table livedata alter column pricechanged set not null;
ALTER TABLE

-- 
Christian