[Haskell-cafe] A small Darcs anomoly

[Andrew Coppin]

On 24/04/2011 06:33 PM, Jason Dagit wrote:
>
>
> On Sun, Apr 24, 2011 at 2:05 AM, Andrew Coppin
> <andrewcoppin at btinternet.com <mailto:andrewcoppin at btinternet.com>> wrote:
>
>     So I was a little surprised to discover that... Darcs doesn't
>     actually support doing this. Darcs is only really interested in the
>     result of applying *all* changes in a repo.
>
>     It seems daft to me that you would design a sophisticated system for
>     splitting history into independent chunks, and then not let me
>     manipulate them independently.
>
>
> This is because of a deliberate choice that was made by David Roundy.
> In darcs, you never have multiple branches within a single darcs
> repository directory tree.

Yes, this seems clear. I'm just wondering whether or not it's the best 
design choice.

> To get the effect you want, you simply
> create two repositories.  One having only the patches for ghc 6.6 and
> one having the patches of ghc 7.0 and then you pull just the patches you
> want from 7.0 into 6.6.  There are options to 'darcs get' that help you
> select the right set of patches to help you create the two repositories.

It does mean that you duplicate information. You have [nearly] the same 
set of patches stored twice, and you're not really storing the history 
of the relationship between two branches, only the history of the branch 
itself.