[Haskell-cafe] I think I've found a regression in Haskell Platform, but what do I do next?

Nick Frolov nf at mkmks.org
Tue Feb 22 16:08:12 CET 2011


Recently I had to switch from ghc 6.12.3 to ghc 7.0.1 because of the bug
#4235. This switch has introduced a problem with one of third-party
libraries I use ('satchmo', an interface for SAT solvers).

The problem is that writing to stdin of a process started by
System.Process.runInteractiveCommand silently fails provided it's stderr
is not read. If stderr of the spawned process is redirected to /dev/null
or fully read by the parent process, then problem does not come up. The
troubled code is available at http://bit.ly/dNwrIV (lines 43-45).

Changes between versions of the 'process' library ( ->
bundled with ghc 6.12.3 and 7.0.1 only include one bug fix, which is not
the source of the problem described, as far as I can understand. The
problem is not present with ghc 6.12.* at all. 

Something has definitely changed between these two ghc versions. Since
I've spent considerable amount of time on finding a workaround for the
problem, I'd like to file a real bug report, but I'm not completely sure
where to do it because there are several pieces of software involved
(ghc itself, 'process', 'satchmo' and 'minisat2' SAT solver). Could
somebody guide me please?

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