[Nix-dev] fixed-output derivation that *also* depend on (some of) its inputs?

[Vladimír Čunát]

On 09/20/2014 09:55 PM, Bjørn Forsman wrote:
> Since fetchurl (via the nixos tarball mirror) downloads the same old
> file (even though it creates a new store path), the result outputHash
> is the same as before. So evaluation doesn't stop but continues on
> with old/wrong data.

If fetchurl *did* download any other data, then it would fail while 
checking the hash. That was my point. Nixos tarball mirror may be 
different and download the same content, but in any case that doesn't 
change the plain fact of the first sentence of this paragraph.

I think we all agree on how fetchurl works, but I still have no idea 
what you desire. I may be an exception, but I don't see what could be 
done "between" the current fixed-output and standard derivations. Either 
you do know what exactly the output should look like and then it doesn't 
really matter how you arrive at it, or you don't know it and then you 
have a standard derivation.


Vladimir


-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 3251 bytes
Desc: S/MIME Cryptographic Signature
Url : http://lists.science.uu.nl/pipermail/nix-dev/attachments/20140921/5b198dbb/attachment.bin