[Haskell-cafe] Has anybody tried to upgrade Cabal on HP (Win 7)

[Duncan Coutts]

On 18 June 2010 15:48, Daniel Kahlenberg <d.kahlenberg at googlemail.com> wrote:
> Hello,
>
> I recently installed HP 2010.1.0.0 within Windows 7 and wanted to
> upgrade the Cabal package to 1.8.0.6 today, sadly I got stuck on a
> failure building the "directory" package.
>
> So I tried to isolate the messages a bit and gave the following a try in
> a ghci session (1st time only with path to cygwin binaries/2nd time only
> with path to msys binaries added on my path variable, for both times I
> append the logging output):
>
> Prelude System.Cmd>
>> rawSystem "cabal" ["upgrade", "--constraint=base==4.*", "directory",
>> "-v3", "--user",
>> "--build-log=d:/temp/log/build-$$pkgid-$$compiler.log"]
>
> Maybe we can find the cause?!

I should note that in the current development version of the 'cabal'
program, I have disabled the 'upgrade' command entirely. Your current
problem is a good example of why I have done this.

By using 'cabal install Cabal' rather than 'cabal upgrade Cabal' you
would not have been led up the blind alley of trying to install a new
version of the directory package. The fact is that you do not want to
install a new version of the directory package. You want to use the
version you have already got.

The root problem is that 'cabal upgrade' is misleading. It does not do
what people expect. It currently means "install the latest version of
this package, and the latest version of all of its dependencies". That
is not useful because you do not want to install the latest version of
core packages like directory. The behaviour of 'cabal install' is what
you want, it means "install the latest version of this package, but
try to use existing installed versions of all dependencies".

Duncan