387c513d12
In order to build the package databases that we will use when compiling a Haskell package, we iterate over the relevant dependencies, and if they contain a package db, we copy its contents over. So far so good, except when one of those dependencies is GHC. This doesn't happen ordinarily, but it will happen when we construct the package database for compiling `Setup.hs`. This is compiled for the build architecture, so we get the build deps, including both the native and the cross GHC (if there is one). In this case, we end up copying the packages from the GHC's package database. This is at best unnecessary, since we will get those packages from the GHC when we compile with it. At worst, however, this is semantically questionable. We can end up having multiple copies of e.g. Cabal with the same version, but (potentially) different contents. At the moment, GHC will expose one of these at semi-random depending on which one it looks at "first". However, there is a MR open [in GHC](https://gitlab.haskell.org/ghc/ghc/merge_requests/545) which as a side effect will instead expose both, leading to ambiguous module warnings (which is not unreasonable, since it *is* ambiguous). So what can we do about it? The simplest solution is just to not copy the package databases from GHC. GHC is special in this regard, so I think it's okay to treat it specially. This PR should have no effect on anything now, but will prevent any breakage when/if the GHC patch lands. Closes https://github.com/NixOS/nixpkgs/pull/57706. |
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| .github | ||
| doc | ||
| lib | ||
| maintainers | ||
| nixos | ||
| pkgs | ||
| .editorconfig | ||
| .gitattributes | ||
| .gitignore | ||
| .version | ||
| COPYING | ||
| default.nix | ||
| README.md | ||
Nixpkgs is a collection of packages for the Nix package manager. It is periodically built and tested by the Hydra build daemon as so-called channels. To get channel information via git, add nixpkgs-channels as a remote:
% git remote add channels https://github.com/NixOS/nixpkgs-channels.git
For stability and maximum binary package support, it is recommended to maintain
custom changes on top of one of the channels, e.g. nixos-18.09 for the latest
release and nixos-unstable for the latest successful build of master:
% git remote update channels
% git rebase channels/nixos-18.09
For pull requests, please rebase onto nixpkgs master.
NixOS Linux distribution source code is located inside
nixos/ folder.
- NixOS installation instructions
- Documentation (Nix Expression Language chapter)
- Manual (How to write packages for Nix)
- Manual (NixOS)
- Community maintained wiki
- Continuous package builds for unstable/master
- Continuous package builds for 18.09 release
- Tests for unstable/master
- Tests for 18.09 release
Communication:
Note: MIT license does not apply to the packages built by Nixpkgs, merely to the package descriptions (Nix expressions, build scripts, and so on). It also might not apply to patches included in Nixpkgs, which may be derivative works of the packages to which they apply. The aforementioned artifacts are all covered by the licenses of the respective packages.