nix-shell invocation from README fails

[tensorflow]

nix-shell invocation from README fails

[nh2]

(I'm on commit 4ab9cb9cf274e88eababfaba85103e3890a96afc of tensorflow/haskell.)

[fkm3]

@grwlf, do you know the answer?

[nh2]

It looks like you're using something somewhere on nixpkgs master; I recommend for reproducibility that you provide a git commit of nixpkgs master, then one can invoke nix-shell specifically with that commit for total reproducibility.

[nh2]

I managed to build it with

env NIX_PATH=nixpkgs=https://github.com/NixOS/nixpkgs/archive/7d36ae33df.tar.gz nix-shell tools/userchroot.nix --pure
stack --stack-root $PWD/stack-root build --system-ghc

3 changes here to what's in the README:

• Gave explicit nixpkgs version (that one is one recent one from nixpkgs unstable, the 17.03 version didn't work)
• --stack-root to have it not use my user's ~/.stack that may contain things I built before for other projects that don't work inside the nix environment, with errors like /host/raid/stack/setup-exe-cache/x86_64-linux/Cabal-simple_mPHDZzAJ_1.24.2.0_ghc-8.0.2: error while loading shared libraries: libgmp.so.10: cannot open shared object file: No such file or directory
• --pure so that external environment variables can't mess with it being reproducible

[blackgnezdo]

@nh2 please turn this into a PR?

[nh2]

@grwlf You added Nix support a short while ago, can you confirm if it builds fine with the nixpkgs commit that I use above?

[grwlf]

Hi, Sorry for delay, I'll check the problem soon.

[grwlf]

Yes, the problem was caused by incompatible nixpkgs tree. Thanks for the suggestions, they all make sense. I'll check nixpkgs version you have provided in a couple of days.

[nmattia]

I think the --stack-root issue is better handled with an export STACK_ROOT=$PWD/stack-root shell hook in tools/userchroot. However I believe a simpler solution would be to use stack --nix instead, I've create #168 . stack --nix foo also makes sure that nix- and non-nix-built packages aren't mixed up.

[jyp]

Is there a guide to build with nix? (I could build but the test suite fails, see #169)

@nmattia I see that your PR is still not merged after all this time. Is it obsolete?

[nmattia]

It shouldn't be obsolete. I think we're waiting for a review from @grwlf .

[fkm3]

The nix code has been updated quiet a bit, hopefully this is fixed now. Re-open if not.