I've started trying to compile this change.

Builds fine!

Tested on x86_64 NixOS on my end, Rust and Cargo build just fine but if I try to build ripgrep or other rust packages with it using nix I get the following error:

building path(s) ‘/nix/store/ip40a32hp1mx5vd3qi79a13hcphkx0qy-ripgrep-0.6.0’                                                                                             
unpacking sources                                                                                                                                                        
unpacking source archive /nix/store/1s01kdhzmrpa97051k0s7b53230bknk4-ripgrep-0.6.0-src                                                                                   
source root is ripgrep-0.6.0-src                                                                                                                                         
Using cargo deps from /nix/store/9vqyrlz7qji6q9jb07wpbdwdi56vn26f-ripgrep-0.6.0-fetch                                                                                    
Using indexHash '-ba82b75dd6681d6f'                                                                                                                                      
Using rust registry from /nix/store/2chf0n5c4mdb6m82ym7wh1wyqdp8vdgw-rustRegistry-2017-08-24                                                                             
warning: custom registry support via the `registry.index` configuration is being removed, this functionality will not work in the future                                 
error: failed to open: /tmp/nix-build-ripgrep-0.6.0.drv-0/deps/registry/index/-ba82b75dd6681d6f/.cargo-index-lock                                                        
                                                                                                                                                                         
Caused by:                                                                                                                                                               
  Permission denied (os error 13)                                                                                                                                        
builder for ‘/nix/store/w2340z8llwwbf0xm7zrinpij4sh2n36w-ripgrep-0.6.0.drv’ failed with exit code 101                                                                    
error: build of ‘/nix/store/w2340z8llwwbf0xm7zrinpij4sh2n36w-ripgrep-0.6.0.drv’ failed

nice! will test it tonight :)

it builds successfully on 17.09pre112899.129f8d7e99 (Hummingbird), but I can confirm the issue reported by @MP2E

Well, reproducible builds is one of the things we all love nix for :)
Anyway, I have no idea yet why .cargo-index-lock appears to be inaccessible :/

might as well do rustc to 1.20 at this point, since that was announced a few days ago

I've already tried it, but it doesn't even build out-of-box for me. Given I still haven't fixed the issue reported by @MP2E, I think it has the priority for now.

For what it's worth, I was able to build using 1.18 and 1.19, but when I tried 1.19 and 1.20, I got an error in the Rust test suite (running on Mac OSX 10.12.6): "error: verification with 'FileCheck' failed" (related to rust-lang/rust#37945).

Hi! I was upgrade rust to 1.20, cargo to 0.21.1 in airalab@39efddb
May it be helpful.

I also get the same error as mentioned by @MP2E .

I'm currently looking at rust-lang/cargo#2857 and rust-lang/cargo#2811 to see if I can improve the whole cargo fetch procedure.

This should also get rid of the warning we currently see:

warning: custom registry support via the `registry.index` configuration is being removed, this functionality will not work in the future

@loskutov .cargo-index-lock is inaccessible, because its parent directory has been symlinked from read-only nix store. Maybe the previous cargo did not create that lock file. I tried copying rustRegistry intead of symlinking, but got another errors related to registry.index....

@akru Are you able also to buildRustPackages with your rust 1.20 an cargo 0.21.1 without the error mentioned in @MP2E? I see you pointed rustRegistry directly to nix store and commented out a lot of lines.

@akru I tried your branch, and buildRustPackage worked, but only with sandboxing disabled.

@datakurre Yup, in my opinion the evil in changed behaviour of cargo from v0.19. In my view helper script based on the assumption that cargo don't update the registry with cached value already exist. But new cargo try to update registry at all. I look forward to resolving this issue with sandbox.

A lot of current crates are not usable because the rust version is just too old. I am using the mozilla overlay in the meantime, however this only works for development.
Is someone working on a fix?

@mguentner part of my nixpkgs.overlays may be interesting for you:

  nixpkgs.overlays = [
    (import /path/to/nixpkgs-mozilla)
    (self: super: {
      pijul = super.callPackage "${nix_store}/pijul.nix" { 
        rustPlatform = super.recurseIntoAttrs (super.makeRustPlatform {
          rustc = self.latest.rustChannels.stable.rust;
          inherit cargo;
        });
      };
      
      rustfmt-nightly = super.callPackage "${nix_store}/rustfmt-nightly.nix" { 
        rustPlatform = super.recurseIntoAttrs (super.makeRustPlatform {
          rustc = (self.rustChannelOf { date = "2017-09-20"; channel = "nightly"; }).rust;
          inherit cargo;
        });
      };
    })
  ];

Thank you. How do you handle the out-of-date cargo registry?

Forgot to include this:

   # ...
      rustRegistry = super.callPackage "${nix_store}/rust-packages.nix" { };
   # ...

I'd like to write an automatic updater for rustRegistry :)

@dywedir I've been struggling with how all of the pieces of Rust Nightly + Nix work together -- can you share a full default.nix example for compiling a Rust Nightly app? And, does your solution only work if you are using NixOS? (I'm running NixPkgs on Macosx and using NixOps to deploy to AWS, so I'm hoping your solution works for both mac and nixos.)

@greglearns this definitely works for nixpkgs. You need three points:

• nixpkgs-mozilla overlay
• override rustPlatform for package

(both in ~/.config/nixpkgs/overlays for nixpkgs case. You can do it in each default.nix instead, if you wish)

• typical default.nix for rust package

I.e. rustfmt-nightly/default.nix (named rustfmt-nightly.nix above):

{ stdenv, fetchFromGitHub, rustPlatform }:

rustPlatform.buildRustPackage rec {
  name = "rustfmt-nightly-${version}";
  version = "0.2.7";

  src = fetchFromGitHub {
    owner = "rust-lang-nursery";
    repo = "rustfmt";
    rev = "nightly-${version}";
    sha256 = "0xqjdq8g40nkqfrkzl9sj5fq5kqf09gp65zxy8dli4b1ic81lfs3";
  };

  depsSha256 = "0yniynv74v6amvjgiba9lczmshp9sl6qdm9qbblfw782hrkif10x";

  meta = with stdenv.lib; {
    description = "A tool for formatting Rust code according to style guidelines";
    homepage = https://github.com/rust-lang-nursery/rustfmt;
    license = with licenses; [ mit /* or */ asl20 ];
    maintainers = with maintainers; [ dywedir ];
    platforms = platforms.all;
  };
}

There is a PR for rust 1.20.0 (#30088) so this can probably be closed?

@dywedir your rustPlatform override snippet is really useful. Would it be ok to add this to the nixpkgs manual (specifically the part on using the mozilla overlays)?