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 haskell.nix uses IFDs internally in a number of places. This prevents the use of `--option allow-import-from-derivation false` even when `materialized` nix is provided.
* Changes `materialize` function so that it returns the `materialized` path when possible instead of a derivation (updates import-and-filter-project.nix to cope with that).
* Materializes the spdx json file.
* Prevents haskell.nix looking for `cabal.project`, `cabal.project.local` and `cabal.project.freeze` files in hackage packages and the ghc-extra-projects.
* SPDX: Clean up attrset style
* SPDX: Include FSF-libre when determining free-ness
In Nixpkgs any license considered free or open source by both the FSF
and the OSI is considered free. When implementing the SPDX parsing I
must've missed the `isFsfLibre` property. This is now fixed.
Fixes#1263
* SPDX: Provide default for isFsfLibre
The `isFsfLibre` property isn't always included, as opposed to the
`isOsiApproved` property. To avoid errors we default it to `false` if
it's missing.
I opted for the simpler, more verbose way to write this.
`lic.isFsfLibre or isOsiApproved` would work as well and reads well but
it's not immediately clear that we're testing whether the field exists
and defaulting rather than doing a boolean OR.
* Add parser combinators to parse SPDX license expressions
The most important parser is `compoundExpression` it parses any SPDX
license expression into a list of SPDX simple-expressions.
The rationale is Nixpkgs' license metadata isn't capable of
distinguishing between the AND and OR relationships.
License exceptions aren't currently taken into account.
* Add tests for the SPDX parser combinators
I simply added a file with expressions that are expected to fail to
parse or parse successfully.
* Add the SPDX license list
The SPDX license list as attrsets following the nixpkgs lib.licenses
convention.
This uses fetchurl which is not ideal because it's not available during
pure evaluation.
It does not yet include the SPDX exceptions list.
* Refactor cabal-licenses.nix to use spdx/licenses.nix
The handling of the generic licenses is undecided still. Some have been
removed because they have better official identifiers.
* Refactor license mapping in builders
The common code in the comp- and setup-builders has been extracted and
refactored to use the SPDX expression parser.
* Use spdx-license-list-data from nixpkgs
This conveniently solves the impurity problem with using fetchurl : )
I'm not sure threading `pkgs` through everything to get access to the
spdx license list package is the right way to go about this.
* hscolour to "LGPL-2.1-only" and remove "LGPL"
* Use evalPackages for spdx and move shim to overlay
* Better fix for LGPL packages.
Co-authored-by: Hamish Mackenzie <Hamish.Mackenzie@iohk.io>
Hamish Mackenzie
toonn