cc @mpickering

@brainrape Perhaps you can try the heavily refactored infrastructure I have submitted in #31327 ?

I think this problem is fixed there.

@mpickering Looks like #31327 is stalled, in the mean time can we merge this one line change that fixes all the Idris libraries?

@brainrape It worked properly last time I tried it? In what sense do you mean it is stalled?

I don't have merge access to merge this change anyway sorry.

@mpickering I support #31327, appreciate the work done there, and would like to see it merged. However, I got the impression that it is not making progress towards being merged (changes requested, possibly further review required, conflict with master). In the mean time we could have working Idris modules in master with this small, easy to review PR.

OK, I can't merge this but #31327 is finished from my perspective. I'll try to rebase it now.

Thank you! Here's hoping it will make it all the way in this time. I'll close this when it does.

Your change was already merged.

69d4ade

@mpickering I'm not sure what you mean, the above commit seems unrelated to this. But lightyear and other idris libraries are broken in current master and need this PR to be fixed. Build output below:

└──> git show-ref HEAD
cff5eec3825f6158f8296eb194c2b1d53d36cad8 refs/remotes/origin/HEAD
└──> nix-shell -f . --attr idrisPackages.lightyear
error: attribute ‘platforms’ missing, at /home/ssdd/dev/nixpkgs/pkgs/development/idris-modules/lightyear.nix:25:11
(use ‘--show-trace’ to show detailed location information)

Yes sorry, my comment was wrong.

I rebased my other branch now if you want to try that for your use case.

@mpickering I checked out your branch and the Idris modules are still broken, and fixed by this PR in the same way. In conclusion, the two PRs are unrelated and this should definitely be merged in any case.
@shlevy could you do the honors? Thanks!

How are you building the packages? Are you using with-packages?

I included the build command and output, two comments up.

Yes, eventually, I would use the lightyear derivation as an argument to with-packages in my project. But evaluating the derivation fails before that.

Your command doesn't work for me.

I then tried nix-shell -p idrisPackages.lightyear which works fine for me locally.

87636ac3115920c71415f47ba6390031b01884d8git

You can see that the platforms attribute is set in meta in lightyear.nix.

To actually try to build the lightyear package (and not just start a shell in the build env as above), I'd use nix-build /path/to/nixpkgs --attr idrisPackages.lightyear

yes, that works fine for me.

nix-shell -p does build idrisPackage.lightyear, it creates a shell with idrisPackage.lightyear available.

You can see the platforms attribute is set in the lightyear deviation?

You have to add -f /path/to/nixpkgs, otherwise nix-shell will use NIX_PATH which is usually managed by nix-channel, possibly nixos-17.10 when it still worked, instead of your local checkout of nixpkgs.

My NIX_PATH points to my local nixpkgs.

[root@nixos:~/devel/nixpkgs]# echo $NIX_PATH
nixpkgs=/root/devel/nixpkgs:nixos-config=/etc/nixos/configuration.nix

You can look in the lightyear derivation and see that it sets platforms! I don't know what else to suggest sorry.

@mpickering yes, lightyear.nix sets platforms, but by inheriting from idris.meta, which is the one defined in idris-wrapper.nix and doesn't have a platforms attribute, which is exactly what this PR fixes!

Not sure why you can't reproduce. The commit you mentioned above is broken for me, and works if I add the line in this PR.

Which platform are you on?

I can't find anther use of symlinkJoin which sets any meta attribute.

My platform is NixOS, as stated in the PR description. x86_64. I don't get it.. that attribute is really missing, and any package that uses idris-wrapper.nix and tries to inherit its platforms will surely fail, plain as day.
Not sure how symlinkJoin fits in the picture... I read the source at https://github.com/NixOS/nixpkgs/blob/master/pkgs/build-support/trivial-builders.nix#L76 and it just passes on the args you give it, more or less.

Here's the story again, if it wasn't clear from the description. There's an idris package that has a meta.platforms attribute. Lightyear inherited the platforms attribute from it. But then idris-wrapper was created to address #10450 and replaced idris in lightyear etc. It did not define a platforms attribute. So the the packages that tried to inherit it, like lightyear, failed with attribute not found. So I added the attribute.

I suspect you're somehow not building the right nixpkgs. I don't see how anything else (eg. sandbox) could affect this, I traced the evaluation and couldn't find any way to divine platforms.

This discussion is getting a bit out of hand for a straightforward one-line change, and I'm sorry to mention this but a lot of the above comments didn't check out. I'm convinced though that we're both acting in good faith and want the same thing (working nixpkgs) so maybe we need a fresh perspective. Let's let someone else take a look. @joachifm could you check this out please?

Basically:

nix-build /path/to/nixpkgs --attr idrisPackages.lightyear

On current master, It should fail with error: attribute ‘platforms’ missing, and this PR will fix it so should be merged. If not, I missed something weird, but it still fails for me, and we should find out why.
Thank you, and happy coding!

@infinisil tried it on IRC and got the same error message as you. I really wish I could reproduce this.. I have tried on master and my branch.

@GrahamcOfBorg build idrisPackages.lightyear

I am worried we're having some problems with non-reproducibility, reported by @FRidh earlier today: #33362 (comment)

@GrahamcOfBorg build idrisPackages.lightyear

Failure on aarch64-linux (full log)

Package ‘jailbreak-cabal-1.3.2’ in /var/lib/gc-of-borg/nix-test-rs-3/repo/38dca4e3aa6bca43ea96d2fcc04e8229/builder/grahamc-aarch64-community-3/pkgs/development/haskell-modules/hackage-packages.nix:118872 is not supported on ‘aarch64-linux’, refusing to evaluate.

a) For `nixos-rebuild` you can set
  { nixpkgs.config.allowBroken = true; }
in configuration.nix to override this.

b) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
  { allowBroken = true; }
to ~/.config/nixpkgs/config.nix.

Success on x86_64-linux (full log)

Installing Lightyear/Char.ibc to /nix/store/cgn32wwnynwjnrkfj60jcx1chf9bn24z-lightyear-2017-09-10/lib/idris-1.2.0/lightyear/Lightyear
Installing Lightyear/Testing.ibc to /nix/store/cgn32wwnynwjnrkfj60jcx1chf9bn24z-lightyear-2017-09-10/lib/idris-1.2.0/lightyear/Lightyear
Installing 00lightyear-idx.ibc to /nix/store/cgn32wwnynwjnrkfj60jcx1chf9bn24z-lightyear-2017-09-10/lib/idris-1.2.0/lightyear
post-installation fixup
shrinking RPATHs of ELF executables and libraries in /nix/store/cgn32wwnynwjnrkfj60jcx1chf9bn24z-lightyear-2017-09-10
strip is /nix/store/5qj61lcvzlap87rf6blvf8p577d482bv-binutils-2.28.1/bin/strip
stripping (with command strip and flags -S) in /nix/store/cgn32wwnynwjnrkfj60jcx1chf9bn24z-lightyear-2017-09-10/lib 
patching script interpreter paths in /nix/store/cgn32wwnynwjnrkfj60jcx1chf9bn24z-lightyear-2017-09-10
checking for references to /tmp/nix-build-lightyear-2017-09-10.drv-0 in /nix/store/cgn32wwnynwjnrkfj60jcx1chf9bn24z-lightyear-2017-09-10...
/nix/store/cgn32wwnynwjnrkfj60jcx1chf9bn24z-lightyear-2017-09-10

^ is this on this branch or master?

Failure on x86_64-darwin (full log)

patching script interpreter paths in /nix/store/iy8qq9y5shs7gnmyw1k9ia15jighag3x-aeson-1.2.3.0
strip is /nix/store/5a88zk3jgimdmzg8rfhvm93kxib3njf9-cctools-binutils-darwin/bin/strip
patching script interpreter paths in /nix/store/10nmnly3n0xq9jjh6y899r7v62naxn0f-aeson-1.2.3.0-doc
cannot build derivation '/nix/store/yf8vmbxsqvq8d1r8kh77lylm15whzn5f-idris-1.2.0.drv': 2 dependencies couldn't be built
cannot build derivation '/nix/store/7h423jq9nivjl9zarv5fpzc82jp5i9yq-idris-1.2.0.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/8jk0fhzjv7rxv41qvclq70rqvyd0i3hg-prelude-1.2.0.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/c4ibh1g19di1myyvnmx3sbq0xspxfp3g-base-1.2.0.drv': 2 dependencies couldn't be built
cannot build derivation '/nix/store/vcbpbw968r9ad3rm4wyh0pix75ffwk5g-effects-1.2.0.drv': 3 dependencies couldn't be built
cannot build derivation '/nix/store/nclf56w330vg70rvqpb0cfvycmda5hzp-lightyear-2017-09-10.drv': 4 dependencies couldn't be built
error: build of '/nix/store/nclf56w330vg70rvqpb0cfvycmda5hzp-lightyear-2017-09-10.drv' failed

On this branch

@brainrape on this branch.

I think I can't reproduce this because I have "allowBroken" in my config but I can't work out how to properly disable it.

Interesting… I don't know enough about Idris to understand why the error from Darwin failure doesn't occur on Linux.

@brainrape Thank you very much for your patience. I can now reproduce this after unsetting allowBroken.

@7c6f434c I think the failure is not to do with this patch but an already existing issue.

Yes, but you may want to set a more narrow meta.platforms

The right place would be on the haskell packages which are failing to build. I can't work out why they are though. Merging this is the right thing to do for now I think, however in future I think it would be better to set meta.platforms on a per idris module level as idris modules can call C FFI like haskell modules.

Thank you for all your help in elucidating this issue.