[Haskell-cafe] ANN: darcs 2.3 beta 2

Petr Rockai me at mornfall.net
Thu Jul 9 07:53:47 EDT 2009


Two weeks passed and it is about time to release darcs 2.3 beta 2 (it's already
a day late, sorry about that).

As with beta 1, there is only a single installation package for this release of
darcs: cabalised source. (Please note that the final version with also come
with the legacy autoconf-based buildsystem, for the last time.)

You can either download a tarball from
<http://repos.mornfall.net/darcs/darcs-> and build manually (see
the build instructions in README inside the tarball), or, alternatively, you
can use cabal-install to obtain a copy (the beta release is now available on

        $ cabal update
        $ cabal install darcs-beta

This, if successful, will give you a darcs binary in `~/.cabal/bin` -- you
should probably add that to your PATH.

What's new since beta 1

There are basically two relatively intrusive changes since beta 1. First, I
have added index upgrade functionality to hashed-storage and this is now used
by darcs, so that any bad or incompatible indexes are recreated transparently
by darcs. Moreover, the index format is now architecture-independent, meaning
that repositories shared across multiple architectures should not suffer from
excessive index rebuilding.

Second, Ganesh has done further work on his gzip CRC correction code. There is
a very slight risk of regressions, so if you have around any repositories with
broken CRCs in them, please test this functionality. Moreover, there is now an
option to limit the repair to current repository, avoiding changes in related
branches or caches.

Trent, Thorkil and Eric have done cleanup work and a number of minor fixes for
this release, improving overall quality and polish. One bug in the new indexing
code has been found and reported by Eric and Guillaume independently, and is
fixed in hashed-storage 0.3.4 (which required by this beta).

You can track the release plan and progress at our wiki:

The question of GHC 6.8

Using GHC 6.10.3 or newer is *strongly recommended*. You may 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.

Overall, the status of GHC 6.8 is "semi-supported": for many cases, things will
work just fine, especially if you take a little extra caution with compilation


Petr Ročkai | http://web.mornfall.net
A physicist is an atom's way of knowing about atoms. (George Wald)

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