[Nix-dev] importing nixpkgs from derivation dumps large path
Ganesh Sittampalam
ganesh at earth.li
Fri Mar 3 23:00:45 CET 2017
On 02/03/2017 10:53, Eelco Dolstra wrote:
> On 03/02/2017 08:01 AM, Ganesh Sittampalam wrote:
>
>> I guess that in this case the large tree is the import of the nixpkgs
>> tree. Is there any work around or better way to achieve what I want?
>
> Nix 1.12 has a builtin
> fetchgit function that allows you to say
>
> with import (builtins.fetchgit {
> url = <nixpkgs>;
> rev = "...";
> }) {};
> ...
>
> (I just pushed a fix to allow "url" to refer to paths.)
Thanks! I've had a play with this, but it reruns the git fetch every
time, which takes a few seconds, nearly as long as the nixpkgs fetchgit
- I guess because no hash is specified?
I can see that this behaviour would also be useful in some cases as I
could just update the git ref live, but the evaluation time cost hurts
with what I'm currently trying to do.
Cheers,
Ganesh
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