nix-build fails when "src" contains Unicode characters, i.e. "src = /tmp/créatúr"

[mhwombat]

I have a couple of accented characters in my .cabal file (but only in the description, copyright and author fields). This file works fine when I build it on a non-NixOS system with sandboxes, but on a NixOS system, the nix-build step causes an error:

error: invalid character ‘�’ in name ‘créatúr’
(use ‘--show-trace’ to show detailed location information)

And if I do nix-build --show-trace, I get:

error: while evaluating the attribute ‘src’ of the derivation ‘haskell-creatur-5.9.6’ at "/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/development/haskell-modules/generic-builder.nix":123:3:
invalid character ‘�’ in name ‘créatúr’

I think this is a bug. Although the call to nix-build is what triggers the error, if I understand correctly, nix-build doesn't know anything about cabal files, so I suspect the problem occurs elsewhere.

The files creatur.cabal, shell.nix, project.nix, and default.nix are here: https://gist.github.com/mhwombat/716cd1cc181bac64991b'

My workflow:

1. I created default.nix.
2. cabal2nix ./. --shell > shell.nix
3. cabal2nix ./. > project.nix
4. nix-shell
5. nix-build (which produces the error)

[vcunat]

In your workflow you run nix-build within a nix-shell? (Looks strange.)

[mhwombat]

I exit nix-shell before running nix-build. (I just use nix-shell to try things out). Sorry for the confusion.

[mhwombat]

I think the problem may be that the directory name itself contains accented characters ("créatúr"). Renaming the directory seems to have got me past that point.

[peti]

nix-build can't cope with the Unicode characters in src. This is a bug in Nix, IMHO.

[Profpatsch]

(triage) I supposed this hasn’t changed yet? If you create an issue in the nix repo we can close here.

[lukateras]

Can't reproduce this with src anymore:

$ cat default.nix 
{ pkgs ? import <nixpkgs> {} }:

with pkgs;

stdenv.mkDerivation {
  name = "creatur";
  src = "/tmp/créatúr";
}
$ nix-build
these derivations will be built:
  /nix/store/kaz4iwkk2ng7ml42b6qy1vb64b1irn3x-creatur.drv
building path(s) ‘/nix/store/jjcvrmjk7q47iyzkgzw21ncmk53zv7bk-creatur’
unpacking sources
unpacking source archive /tmp/créatúr
do not know how to unpack source archive /tmp/créatúr
builder for ‘/nix/store/kaz4iwkk2ng7ml42b6qy1vb64b1irn3x-creatur.drv’ failed with exit code 1
error: build of ‘/nix/store/kaz4iwkk2ng7ml42b6qy1vb64b1irn3x-creatur.drv’ failed

However, name should still be Nix store compatible, and that means no Unicode characters.
That's intended, see NixOS/nix#842:

$ cat default.nix 
{ pkgs ? import <nixpkgs> {} }:

with pkgs;

stdenv.mkDerivation {
  name = "créatúr";
  src = "/tmp/créatúr";
}
$ nix-build
error: invalid character ‘�’ in name ‘créatúr’