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).
Currently if you try to build a ghcjs version that does not exist
haskell.nix falls back on the GHC version. Once ghcjs is in the
ghc tree this will work, but for now we should have an error
message that is more descriptive than attempting and failing to
build ghc for a js target.
New error looks like this:
```
$ nix-build -A pkgs-unstable.pkgsCross.ghcjs.buildPackages.haskell-nix.compiler.ghc861
error: ghcjs 8.6.1 is no longer supported by haskell.nix. Consider using 8.6.5
```
Fixes ghcjs 8.6.5 and 8.8.4.
Uses emscripten for ghcjs 8.8 and adds scripts for building ghcjs 8.8.
Many fixes for ghcjs test failures.
Includes relocatableConfigFiles for making relocatable ghcjs bundles.
This change introduces a `ghc8102-experimental` compiler-nix-name that behaves much like the `ghc8102` version but includes @JoshMeredith's patch `./patches/ghc/ghc-8.10-ubxt.patch` that writes the `cg_binds` field with:
```haskell
liftIO $ registerInterfaceDataWith "ghc/phase/core" hsc_env $ \bh ->
putWithUserData (const $ return ()) bh (map toIfaceBind $ cg_binds cg_guts)
```
Some of the places where we used to depend on the output of `plan-to-nix` containing the correct `nix-name` for the compiler have been update to avoid using incompatible interface files from the `compiler-nix-name = "ghc8102"` version of GHC.
When building a new GHC in haskell.nix it is often desirable to set the
ifdLevel to make sure tests that use eval time do not run.
Unfortunately when ifdLevel=2 eval time work for the Haskell Language
Server tests runs and builds nix-tools for the first time at eval time.
This is fixed by separating the building of the HLS from the
ifdInputs that are needed for the building.
Changes to the interface of haskell.nix (from the changelog.md file):
* Removed `sources.nixpkgs-default`, use `sources.nixpkgs` instead.
* Removed `./nixpkgs` directory, use `(import ./. {}).sources`
or `./nix/sources.nix` instead.
* Removes V1 interface for details on how to fix old code see:
https://github.com/input-output-hk/haskell.nix/issues/709
* Removed defaultCompilerNixName.
* cabalProject, cabalProject', hackage-project and hackage-package
now require a `compiler-nix-name` argument.
* `haskell-nix.tool` and `.tools` now require a `compiler-nix-name` argument.
New functions `p.tool` and `p.tools` (where p is a project) do not.
Like `shellFor { tools = ... }` they will use the compiler nix name
from the project (including stack projects where it is derived from
the resolver).
* `haskell-nix.alex` and `haskell-nix.happy` have been removed. Use
`p.tool "alex" "3.2.5"` or `shellFor { tools = { alex = "3.2.5"; } }`.
* `haskell-nix.nix-tools` -> `haskell-nix.nix-tools.ghc883` (it includes
the hpack exe now).
* `haskell-nix.cabal-install` ->
`p.tool "cabal" "3.2.0.0"` or `shellFor { tools = { cabal = "3.2.0.0"; } }`
* `haskell-nix.haskellNixRoots` -> `haskell-nix.roots ghc883` or `p.roots`
Other changes:
Adds hpack executable to the nix-tools derivations.
Adds a `cabal-hpack` test to make sure `hpack` works with
`cabalProject`.
Reduces the number of calls to `cabalProject` (particularly when
checking materialization), by giving internal tools a per-compiler
attribute.
Uses happy 1.19.12 when building newer ghc versions.
Updates cabal-install 3.2.0.0 to use the source from github that
is compatible with ghc 8.10.1.
Updates the docs for callCabalProjectToNix.
Adds a license mapping to fix a common warning.
Generalized version of the `cabalProject` and `stackProject`
functions.
Automatically selects the correct project type based on the
`projectFileName` argument if provided or what files exist in
the `src` directory if no `projectFileName` was specified.
If it cannot be determined which it should use the following
error message is given:
```
error: haskell-nix.project : both `stack.yaml` and `cabal.project` files exist set `projectFileName = "stack.yaml;"` or `projectFileName = "cabal.project";`
```
This is a simple way to specify the sha256 values for references
to git repositories that do not have a `--sha256:` comment in the
`cabal.project` file or a `# nix-sha256:` comment in the `stack.yaml`
file.
The tests demonstrate how to use `sha256map` with both
`cabalProject` and `stackProject` to build the
haskell-language-server from github with the sha256 hashes
needed to work with `--option restrict-eval true`.
Hamish Mackenzie
Shea Levy
Hamish Mackenzie
Teo Camarasu