I want to use the uuid type in postgres, have it treated as Text and then add a instance PersistField UUID to do the mapping to UUID in Haskell (since postgresql-simple doesn't want to depend on a specific uuid implementation: lpsmith/postgresql-simple#10).

But if you have a uuid type in a postgres db schema and try to interact with it you get an error from persistent-postgresql:

Postgresql.getGetter: type UUID not supported.

I tried adding a case for this

getGetter PG.UUID = convertPV PersistText

but this produces another error, this time in postgresql-simple:

Incompatible {errSQLType = "uuid", errSQLTableOid = Nothing, errSQLField = "", errHaskellType = "Text", errMessage = "types incompatible"}

except for adding the case to getGetter, what needs to be changed and in which package?