This adds a way to specify the `evalSystem` or `evalPackages` explicitly when calling the `project` functions.
Currently if we want to make a `flake` that supports multiple systems we have few options:
* Require builders for all the supported systems (even just for `nix flake show`).
* Pass `--impure` so that haskell.nix can see `builtins.currentSystem` to set up `pkgs.evalPackages` to use that. Unfortunately this prevents nix from caching some of the work it does and often results in it recalculating for each supported system when it would otherwise be cached and take no time at all.
* Add an overlay to replace `evalPackages`. This works, but it is not straight forward.
* Materialize the nix files for the project.
This change allows `evalSystem = "x86_64-linux";` to be passed telling `haskell.nix` to run `cabal` and `nix-tools` on that system. The user will have to have a builder for that system, but does not need to have builders for the others (unless building outputs for them).
`runCommandLocal` sets both `preferLocalBuild=true` and
`allowSubstitutes=false`. There's an
[argument](https://github.com/NixOS/nix/issues/4442) that the latter is a
misfeature. There's really no reason not to download something from a
substitutor if it's actually been built already.
We can get the effect that we want easily enough by just setting
`preferLocalBuild=true` alone.
* Improve support for external Hackage repositories
This change builds #535. `repository` blocks in `cabal.project` parsed and `cabal` is used to automatically downloaded them. Then `hackage-to-nix` is used to produce the nix required.
To make it work with restricted eval (on hydra for instance) we need to include a sha256 like this:
```
repository ghcjs-overlay
url: https://input-output-hk.github.io/hackage-overlay-ghcjs
secure: True
root-keys:
key-threshold: 0
--sha256: sha256-EPlLYPmIGtxeahlOspRzwJv+60N5mqrNC2BY4jZKceE=
```
To find the correct `sha256` put in an invalid one and attempt a build.
* Throw better error when conf files are missing
Previously, if some directories were missing .conf files, an error like
this would be thrown:
cp: missing destination file operand after '/nix/store/pnmrz06g0sa4s3yx53hgmr9k8jrh6ww0-ouroboros-network-framework-lib-ouroboros-network-framework-0.1.0.0-haddock-config/lib/ghc-8.6.5/package.conf.d'
While normally this shouldn't occur, I've seen it happen in CI anyways,
with the problem disappearing if the store path that's missing the files
was rebuilt a couple times.
With this commit, it becomes much easier to figure out which store path
is missing the files, which would be very hard to figure out from the
previous message.
Although the default ghc used by haskell.nix is ghc 8.6.5 many of
the tools used in haskell.nix are still built with the boot compiler
ghc 8.4.4. These include
* haskell-nix.cabal-install
* haskell-nix.alex
* haskell-nix.happy
This change updates those to ghc 8.6.5 and includes materializations
for the new versions.
When cabal-install is built it is careful to disable materialization
checks on the version of itself used during the build to avoid
infinite recursion.
There was a version of nix-tools built with the boot ghc which was
only used when `checkMaterialization = true`. It was used for
the boot versions of alex, happy and hscolour. These have been update
to use the default (ghc 8.6.5) version of nix-tools and
checkMaterialization is forced off when they are being used to build
ghc. This means the materialization will only be checked for these
when they are built independently (they are included in the test set
via haskellNixRoots).
Three new arguments are added to `default.nix`:
* `defaultCompilerNixName` if not specified "ghc865" is used
* `checkMaterialization` makes it easier to switch on materialization checks
* `system` defaults to `builtins.currentSystem`
This change also moves the work needed for hydra eval to the eval
system using a new `evalPackages` feature. This includes:
* Fetching from git with `fetchgit`
* Building scripts with `runCommand` and `writeTextFile`
* `git ls-files` in `cleanGit`
* running `cabal v2-configure`
* copying materialized files (we are not sure why this is necessary but
if we do not `cp -r` the files nix will not load them on hydra)
Reduce size of `make-config-files.nix` strings by around 80%.
These are unlikely to be the cause of hydra eval time memory
issues in the GB range, but were still quite large (around 10MB for the
`cabal-simple` test case).
There was issue causing excessive builds of the `git` package when
cross compiling. Gory details are a comment in `lib/defaults.nix`
but in short if you use `git` you need an extra `.buildPackages`
one is not enough because it depends on `gdb` and that will
be different in `buildPackages` compared to
`buildPackages.buildPackages`.
Adds missing materialization files for ghc 8.4.4 (only needed
when `checkMaterialization` is on because of other
materialiazations, but good to have).
* Add support for external Hackage repositories
Currently haskell.nix is not able to build Cabal projects that depend on
packages from private Hackage repositories, as it make only main Hackage
available to cabal. This is unfortunate.
This commit adds this functionality, by allowing the user to pass
`extra-hackages` and `extra-hackage-tarballs` to `mkPkgSet` and
`callCabalToNix` respectively, to add as much extra repositories as
needed.
This repositories are first made available to Cabal when calling
`v2-configure`, resulting in correct plans. Later they are combined with
global Hackage when building dependencies of the local packages.
* Use cabal.project.freeze if available
Currently callCabalProjectToNix does not copy `cabal.project.freeze`
from source directory, leading to different build plans when building
components with nix and when building project with `cabal new-build`
inside `nix-shell`.
This behavior is undesired, so this commits fixes it.
* Add tests for extra-hackages functionality
Co-authored-by: Moritz Angermann <moritz.angermann@gmail.com>
The Overlays branch
This is a major reorganization in how haskell.nix is used, and marks our 1.0 release.
The branch doesn't build due to numerous issues that we believe to be with the CI
and not this branch. We expect only very minor adjustments prior to calling this the
official 1.0 release.
* Move iohk-nix patches into haskell.nix
This moves the customizations we did in iohk-nix
into haskell.nix via overlays and config.
Add bootPkgs logic
this moves the nuking of bootPkgs where it belongs. This should eventually still be
removed and replaced by a proper solution, that doesn't require the nuking of
bootPkgs.
Allow us to bootstrap binary ghcs and a cabal-install
With this we can do the following:
```
$ nix repl compiler/old-ghc-nix
nix-repl> :b (let pkgs = import <nixpkgs> {}; in with import ./. {}; import ./compiler/bootstrap/cabal-install.nix { inherit (pkgs) fetchurl stdenv zlib; inherit hackage
; ghc = ghc844; src = pkgs.fetchurl { url = "https://github.com/haskell/cabal/archive/Cabal-v3.0.0.0-rc3.tar.gz"; sha256 = "1zl2mgg8307ykq3v8nmafc6zdhhj1cw7w8ffpap16dsm6
5lbnx33"; }; })
```
which wile it may look daunting, will allow us to bootstrap a
cabal-install with a ghc. From that point onwards, we should be able to
build any hackage package via haskell.nix.
Pass through cabal-install version
Better threading of arguments.
Add bootstrap overlay
Allow alex + happy to be built
This still has a wart: we need nix-tools, and for that we use the ghc865 from
nixpkgs. Ideally we'd build nix-tools against a specific ghc, but then
we'd need a build expression for that.
Make ghcjs work
Building something like this:
```
nix build '(with import ./. { nixpkgs = ../nixpkgs; nixpkgsArgs = { crossSystem = { config = "js-unknown-ghcjs"; }; }; }; (haskell-nix.hackage-package { name = "hello"; version = "1.0.0.2"; })).components.exes.hello'
```
will now work. Assuming `nixpkgs` has been appropriately patched to support the `js-unknown-ghcjs` triple.
Also: this will need an additional `Cabal` patch, to make `Cabal` understand what it needs to do with: `dist/build/hello/hello: copyFile: does not exist (No such file or directory)`
It needs to learn that `dist/build/hello/hello.jsexe` is what it wants to copy and that that is a directory. Luckily we do have some code in Cabal already that does this for `.exe` on windows.
Build `js-unknown-ghcjs` packages with haskell.nix
Using the following expression:
```
with import ./. { nixpkgs = ../nixpkgs; nixpkgsArgs = { crossSystem = { config = "js-unknown-ghcjs"; }; }; };
let Cabal = buildPackages.haskell-nix.hackage-package {
name = "Cabal"; version = "2.4.1.0";
modules = [
{ packages.Cabal.patches = [ ./Cabal-install-folder.diff ]; }
];
}; in
(haskell-nix.hackage-package {
name = "hello"; version = "1.0.0.2";
modules = [
({config, ... }:{ packages.hello.package.setup-depends = [ Cabal ]; })
];}).components.exes.hello
```
in a `test.nix` file. And running
```
nix build -f ./test.nix
```
on it, will produce
```
./result
├── bin
│ └── hello.jsexe
│ ├── all.js
│ ├── all.js.externs
│ ├── index.html
│ ├── lib.js
│ ├── manifest.webapp
│ ├── out.frefs.js
│ ├── out.frefs.json
│ ├── out.js
│ ├── out.stats
│ ├── rts.js
│ └── runmain.js
└── share
└── doc
└── x86_64-linux-ghc-8.6.5
└── hello-1.0.0.2
└── LICENSE
6 directories, 12 files
```
* This adds more logic for the cabalProjectToNix idf
That is, something like this:
```
nix-build --expr 'with import ./. {}; callCabalProjectToNix { index-state = "2019-04-30T00:00:00Z"; src = /some/path; }'
```
should produce something that can be build with mkCabalProjectPkgSet.
* Make sure the hackageTarball's store path doesn't change
previously the fetchurl would produce a different store path each
and every time as hackage's index is a moving target. With this
impurity setup, we can ignore this.
* Fix test
* Proper name
* Re-enable test
* Allow to parameterize over the `system` for the test default.nix
* Copy instead of link for ifds.
This makes me really sad.
