haskell/with-packages-wrapper.nix: install "doc" outputs

[matthewbauer]

We were previously just installing the "out" output which broke when
we recently changed to generating multiple outputs.

Fixes #76837

Motivation for this change

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

Notify maintainers

cc @

[cdepillabout]

@matthewbauer Could you show me how to test that this actually fixes the problem with hoogle?

My idea was to run a command like the following on the current master:

$ nix-build -E 'with import ./. {}; haskellPackages.ghcWithPackages (p: [p.conduit])'
/nix/store/48grjcgskic4iij38sgdfx4f4q7r0hlr-ghc-8.6.5-with-packages

This works, as expected. In the /nix/store/48grjcgskic4iij38sgdfx4f4q7r0hlr-ghc-8.6.5-with-packages directory, there is no share/doc directory (as expected?).

I then checked out this PR and tried to run the same command, but I got an error:

$ hub checkout https://github.com/NixOS/nixpkgs/pull/76842
$ nix-build -E 'with import ./. {}; haskellPackages.ghcWithPackages (p: [p.conduit])'
these derivations will be built:
  /nix/store/chk26hff7nhhzjyjj5fk80xm3rw3v597-ghc-8.6.3-with-packages.drv
building '/nix/store/chk26hff7nhhzjyjj5fk80xm3rw3v597-ghc-8.6.3-with-packages.drv'...
created 131 symlinks in user environment
rm: cannot remove '/nix/store/0s4vjgsz437aqmpyxxr5zqdcdcdih57j-ghc-8.6.3-with-packages/bin/ghc': Permission denied
builder for '/nix/store/chk26hff7nhhzjyjj5fk80xm3rw3v597-ghc-8.6.3-with-packages.drv' failed with exit code 1
error: build of '/nix/store/chk26hff7nhhzjyjj5fk80xm3rw3v597-ghc-8.6.3-with-packages.drv' failed

I don't understand two things:

1. Why is this trying to use ghc-8.6.3 (and not the latest version of ghc, 8.6.5)? Is this PR branched off of an old version of nixpkgs? Could you rebase it on top of the current master?
2. It is probably bad that this is failing, right?

[matthewbauer]

1. Why is this trying to use ghc-8.6.3 (and not the latest version of ghc, 8.6.5)? Is this PR branched off of an old version of nixpkgs? Could you rebase it on top of the current master?

Yeah this was based off of git merge-base origin/release-19.03 origin/release-19.09 so that it can be merged into master, release-19.09 and release-19.03. It definitely can be rebased, but ideally this fix would be merged into all three branches.

2. It is probably bad that this is failing, right?

Yeah this is definitely an oversight. It looks like it is a result in moving from symlinkJoin to buildEnv.

[cdepillabout]

@matthewbauer

Yeah this was based off of git merge-base origin/release-19.03 origin/release-19.09 so that it can be merged into master, release-19.09 and release-19.03.

Oh, I see. That's really smart! I'm happy with this as-is, then. No need to rebase.

It looks like it is a result in moving from symlinkJoin to buildEnv.

I've tested your fix in 93aabab and this appears to be working for me.

$ nix-build -E 'with import ./. {}; haskellPackages.ghcWithPackages (p: with p; [aeson conduit lens servant-server])'
...
/nix/store/c36g05zmrflibzy5w6wji2zc0nmry3sf-ghc-8.6.3-with-packages
$ ls /nix/store/c36g05zmrflibzy5w6wji2zc0nmry3sf-ghc-8.6.3-with-packages/share/doc/
adjunctions-4.4
aeson-1.4.2.0
ansi-terminal-0.8.2
...

[matthewbauer]

Also it's usually worth trying the GitHub merge commit to test PRs. I think nix-review does this for you, but you can also use something like & test merge_commit_sha directly:

nix-build -E "(import (builtins.fetchTarball \"https://github.com/NixOS/nixpkgs/archive/$(curl https://api.github.com/repos/NixOS/nixpkgs/pulls/76842 | jq -r .merge_commit_sha).tar.gz\") {}).haskellPackages.ghcWithPackages (p: [p.conduit])"