Determining client_encoding from client locale

We currently require that you set client_encoding correctly, or you get
garbage in psql and any other tool using libpq. How about setting
client_encoding automatically to match the client's locale? We have
pg_get_encoding_from_locale() function that we can use to extract the
encoding from LC_CTYPE. We could call that in libpq.

client_encoding defaults to server_encoding, which is correct in the
typical environment where the client and the server have identical
locale settings, which I believe is why we don't see more confused users
on mailing lists. However, a partner of ours was recently bitten by
this. That was on Windows; I'm not 100% sure if LC_CTYPE is set
correctly there by default, but this seems like a good idea nevertheless.

We could expand that to datestyle and the user-settable lc_* settings,
but I don't want to go that far. In case the server lc_ctype/collate
settings don't match the client's locale, you would end up with mixed
lc_* settings which might be more confusing than helpful.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com