[arch-haskell] Re: [extra] haskell-parallel

[Magnus Therning]

On Thu, Nov 11, 2010 at 15:20, Peter Simons <simons at cryp.to> wrote:
> Hi Magnus,
>
>  > http://linode3.kiwilight.com/~magnus.therning/archhaskell/x86_64/
>
> I completely agree that the naming scheme is sound. I don't see, however,
> how other packages are going to use it. Could you show us a concrete
> example, please? What does a package like, say haskell-pandoc, depend on?

It's dependencies would be unchanged.

AFAICS there are roughly two sides to consider.  Packages delivered in
binary format, and packages delivered in source format (AUR).

Binary

The burden falls on the developers who provide the binary packages to
make sure that all binary packages are mutually compatible.

Source

The burden falls on the user to make sure that his system is sane.
Unfortunately it's rather simple to end up in a situation where this
isn't the case.  However, this is already true!
Here's an example:

1. User installs haskell-platform, and gets haskell-hp-http 4000.0.9
(which provides haskell-http 4000.0.9)
2. User installs haskell-pandoc from AUR, it's built against HTTP 4000.0.9
3. User now installs haskell-http 4000.0.10 from AUR
4. User now removes haskell-hp-http, without removing/re-installing
haskell-pandoc

Step four is possible, since all the dependencies of haskell-pandoc
are satisfied by the system (haskell-http >= 4000.0.5).  However, I
believe that GHC will complain, but our .install scripts use force and
that shuts GHC up.  After this the system is not in a good state, and
it's unclear whether haskell-pandoc works any more.  We also don't
have any really good tools to assist the user when this situation
occurs.

It should be noted though that this is made no worse by providing haskell-hp-*.

/M

-- 
Magnus Therning                        (OpenPGP: 0xAB4DFBA4)
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