BUG #4862: different results in to_date() between 8.3.7 & 8.4.RC1

The following bug has been logged online:

Bug reference:      4862
Logged by:          Jeremy Ford
Email address:      jeremford@gmail.com
PostgreSQL version: 8.4 RC1
Operating system:   Fedora 10 i386
Description:        different results in to_date() between 8.3.7 & 8.4.RC1
Details:

Running the following query on PG 8.3.7

select
  to_char(2009,'9999') as year,
  to_char(3,'09') as month,
  to_date(to_char(2009,'9999')||to_char(3,'99') ,'YYYYMM') as method1,
  to_date(to_char(2009,'9999')||'-'||to_char(3,'09') || '-01','YYYY-MM-DD')
as method2

results in:
year, month, method1, method2
" 2009";" 03";"2009-03-01";"2009-03-01"

Running exactly the same query on PG 8.4.RC1 gives:
year, month, method1, method2
" 2009";" 03";"0200-09-01";"2009-03-01"

PG 8.3.7    “method1” = "2009-03-01"
PG 8.4.RC1  “method1” = "0200-09-01"

Both databases were on the same machine – Fedora 10 – 32bit (GCC 4.3.2).
Server configured for Australian timezone/usage.

I realize I should have slapped a trim() around the to_char(), but thought
it worth noting the difference anyway.

Cheers,
Jeremy.