cabal install cabal-install with the latest HP on Mac OS X

[Yitzchak Gale]

I installed the 64-bit version of the recent
Haskell Platform release on Mac OS X 10.6.6.

$ cabal --version
cabal-install version 0.10.2
using version 1.10.1.0 of the Cabal library

As always in the past, and as cabal install itself
has often suggested, the first thing I did was to
run 'cabal install cabal-install' to make sure I
have the latest version.

To my surprise, cabal install began installing
an *older* version of itself, together with older
versions of dependent libraries to support that.

I didn't really mind, because I could always just
remove the symlink to the older-versioned cabal
executable when it finished, so I let it run its course
to avoid leaving a mess by aborting. However, after
a while, the installation process failed with the message:

Downloading time-1.1.4...
<command line>: cannot satisfy -package Cabal-1.10.1.0:
    Cabal-1.10.1.0-6289829715de7a109def1f0c286a5dc4 is unusable due to
missing or recursive dependencies:
      process-1.0.1.5-3e412eee765d141be15796c32f22f7a3

Note that process-1.0.1.5 and Cabal-1.10.1.0 are already
installed globally as part of the platform. Another copy of
process-1.0.1.5 had been installed in userland during this
problematic run. Cabal-1.8.0.6 was also installed in userland.

Why did cabal try to downgrade itself to an older version,
and why did it get so confused while trying to do so?

Thanks,
Yitz