[Nix-dev] Kde 4.8 broken in trunk

[Marc Weber]

Excerpts from Vladimír Čunát's message of Tue Feb 07 22:34:55 +0100 2012:
> Building everything against qt48 fixed that for me but I'm not sure how 
> to best modify the expressions so such mistakes don't happen in future.
Of course you could traverse the derivation tree and print warnings if
such cases happen. cmake, autotools etc could be marked as "exceptional
case" - because it usually is fine to have different versions in the
dependency tree.

> Perhaps some kind of deep override... I don't know how you usually do 
> such things. I suppose Yury will want to fix this.

> By the way is there any use case where we want to have different builds 
> of one package in one dependency tree?
Usually no. Its that this case didn't happen that often yet AFAIK.
When there was trouble some kind of deep-overriding was used.

Previous versions of webkit could serve as example. See deep* functions
in all-packages.nix somewhere at the top.

See my comments about "SAT" in the other thread about future of python.
You can make it perfect, but evaluation time will increase much - and
you may die while still adding constraints without even having started
any real build due to complexity. Maybe its worth giving it a try ?

Is it time to create kind of "cabal" for c/c++ libraries so that debian
and nix packages can be derived from those ? ...

I'd still be interested in how well this would work in reality.

My view on this might be incomplete.

Marc Weber