[darcs-users] GHC 6.8?

[Isaac Dupree]

On 03/17/10 09:01, Yitzchak Gale wrote:
> Yes, supporting a range of platform versions is not easy.
>
> But darcs is version control - people's data is at stake.

Unfortunately, (to take this statement in an opposite direction), each 
version of GHC we support has its own *bugs*.  Luckily, none of the 
*known* bugs damages people's *data*, at least if you compile darcs with 
the correct set of flags.  It seems surprisingly risky to support more 
GHC versions than we have to...

to quote from the 2.4 README,

> Using GHC 6.10.3 or newer is STRONGLY RECOMMENDED. You can compile darcs with
> GHC 6.8, but there are several caveats. If you are using 6.8.2 or older, please
> disable mmap support (pass -f-mmap to cabal install or runghc Setup configure
> below). Note that the GHC 6.8.2 that ships with Debian Lenny is not affected
> and it should be safe to keep mmap enabled. It is also recommended to disable
> use of Hackage zlib when compiling with GHC 6.8.2 (including the Debian Lenny
> version): pass -f-zlib to cabal. When using zlib, we have seen occasional
> crashes with error messages like "openBinaryFile: file locked" -- this is a
> known GHC 6.8.2 bug (and is fixed in GHC 6.8.3). Last, if you are using a
> 64-bit system, darcs may hang when you exit a pager when compiled with GHC
> older than 6.10.3. Although this is harmless, it is quite inconvenient.