runghc sometimes won't allow redirecting of stdout/stderr

[simonmic]

See attached test.hs. Here's stdout working normally:

$ runhaskell test.hs | cat
output
$

But after uncommenting either the cmdArgs line or the defaultMainWithArgs line, stdout can't be captured:

$ runhaskell test.hs | cat
$ 

It does appear on the console if you don't redirect though. The same goes for stderr. This prevents me testing uncompiled scripts with shelltestrunner. I'm on mac os 10.5.

[simonmic]

stdout working normally:
 
$ runhaskell test.hs | cat
output
$
 
after uncommenting either commented line below, stdout can't be captured:
 
$ runhaskell test.hs | cat
$ 

[canadaduane]

I just bumped into this bug as well. When running tests in an editor such as TextMate?, this causes the editor to be unable to show the results of the test suite.

In my case, this is true of a simple

main = defaultMain tests

I assume this is caused by Test.Framework somehow?

[igloo]

With 6.13.20100428:

q.hs:

module Main (main) where

import System.Exit

main :: IO ()
main = do putStrLn "Q1"
          exitFailure
          putStrLn "Q2"

$ /home/ian/ghc/darcs/ghc/inplace/lib/runghc -f /home/ian/ghc/darcs/ghc/inplace/bin/ghc-stage2 q.hs
Q1
$ /home/ian/ghc/darcs/ghc/inplace/lib/runghc -f /home/ian/ghc/darcs/ghc/inplace/bin/ghc-stage2 q.hs | cat
$

[simonmar]

Fixed:

Wed May  5 14:38:48 BST 2010  Simon Marlow <marlowsd@gmail.com>
  * runghc: flush stdout/stderr on an exception (#3890)

[igloo]

Merged