Non-ASCII line input does not work with the Haskeline backend.  

The main issue is that Haskeline processes Unicode input and returns decoded Chars, 
but the non-Haskeline backend uses getLine which reads each byte into a separate 
Char.  Darcs stores strings internally using the latter scheme, since it uses 
standard library functions like writeFile, putStr, etc. which ignore all but the 
lowest 8 bits of each Char.

For example (with a UTF-8 console):

Prelude> getLine
[user input:]α
"\206\177"
Prelude> :m +System.Console.Haskeline
Prelude System.Console.Haskeline> runInputT defaultSettings $ getInputLine ""
[user input:]α
Just "\945"


Also, Haskeline requires UTF-8 on Unix, which may be unnecessarily restrictive for 
systems that use ISO-8859 and other such encodings.

The next release of Haskeline (version 0.6) should provide functionality which will 
make these issues easier to resolve.

The following patch updated the status of issue1292 to be resolved:

* Resolve issue1292: re-encode line input from the Haskeline backend. 
Ignore-this: e6c94db8cbef0f8fa3f3d0011c6ef88f
This patch bumps dependencies to haskeline-0.6.* (which provides the required
functionality) and terminfo-0.3.* (which is required by that version of
Haskeline).  Haskeline is also enabled by default now that non-ASCII line input
works correctly.