srid/haskell-flake
1
1
Fork 0
mirror of https://github.com/srid/haskell-flake.git synced 2024-08-15 17:00:41 +03:00
Code Issues Packages Projects Releases Wiki Activity

Make overrides an overlay type rather than a functionTo (#67)

Browse Source
This commit is contained in:
Sridhar Ratnakumar 2023-02-10 15:07:06 -05:00 committed by GitHub
parent 3a515400fd
commit 4585d422cd
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 75 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
CHANGELOG.md
View File

@ -10,6 +10,8 @@
- #37: Group `buildTools` (renamed to `tools`), `hlsCheck` and `hlintCheck` under the `devShell` submodule option; and allow disabling them all using `devShell.enable = false;` (useful if you want haskell-flake to produce just the package outputs).
- #64: Remove hlintCheck (use [treefmt-nix](https://github.com/numtide/treefmt-nix#flake-parts) instead)
- #52: Expose the final package set as `finalPackages`. Rename `haskellPackages`, accordingly, to `basePackages`. Overlays are applied on top of `basePackage` -- using `source-overrides`, `overrides`, `packages` in that order -- to produce `finalPackages`.
- #68: You can now use `imports` inside of `haskellProjects.<name>` to modularize your Haskell project configuration.
- #67: `overrides` will be combined using `composeManyExtensions`, however their order is arbitrary. This is an experimental feature, and a warning will be logged.
## 0.1.0

57
flake-module.nix
View File

@ -99,16 +99,55 @@ in
description = ''Package overrides given new source path'';
default = { };
};
overrides = mkOption {
type = functionTo (functionTo (types.lazyAttrsOf raw));
description = ''
Overrides for the Cabal project
overrides =
let
# WARNING: While the order is deterministic, it is not
# determined by the user. Thus overlays may be applied in
# an unexpected order.
# We need: https://github.com/NixOS/nixpkgs/issues/215486
haskellOverlayType = types.mkOptionType {
name = "haskellOverlay";
description = "An Haskell overlay function";
descriptionClass = "noun";
# NOTE: This check is not exhaustive, as there is no way
# to check that the function takes two arguments, and
# returns an attrset.
check = lib.isFunction;
merge = _loc: defs:
let
logWarning =
if builtins.length defs > 1
then builtins.trace "WARNING[haskell-flake]: Multiple haskell overlays are applied in arbitrary order." null
else null;
overlays =
map (x: x.value)
(builtins.seq
logWarning
defs);
in
lib.composeManyExtensions overlays;
};
in
mkOption {
type = haskellOverlayType;
description = ''
Cabal package overrides for this Haskell project
For handy functions, see <https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/haskell-modules/lib/compose.nix>
'';
default = self: super: { };
defaultText = lib.literalExpression "self: super: { }";
};
For handy functions, see
<https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/haskell-modules/lib/compose.nix>
**WARNING**: When using `imports`, multiple overlays
will be merged using `lib.composeManyExtensions`.
However the order the overlays are applied can be
arbitrary (albeit deterministic, based on module system
implementation). Thus, the use of `overrides` via
`imports` is not officiallly supported. If you'd like
to see proper support, add your thumbs up to
<https://github.com/NixOS/nixpkgs/issues/215486>.
'';
default = self: super: { };
defaultText = lib.literalExpression "self: super: { }";
};
packages = mkOption {
type = types.lazyAttrsOf packageSubmodule;
description = ''

35
test/flake.nix
View File

@ -24,19 +24,34 @@
];
perSystem = { self', pkgs, ... }: {
haskellProjects.default = {
# Multiple modules should be merged correctly.
imports =
let
defaults = {
overrides = self: super: {
# This is purposefully incorrect (pointing to ./.) because we
# expect it to be overriden below.
foo = self.callCabal2nix "foo" ./. { };
};
devShell = {
tools = hp: {
# Setting to null should remove this tool from defaults.
ghcid = null;
};
hlsCheck.enable = true;
};
};
in
[ defaults ];
overrides = self: super: {
# Custom library overrides (here, "foo" comes from a flake input)
# This overrides the overlay above (in `defaults`), because the
# module system merges them in such order. cf. the WARNING in option
# docs.
foo = self.callCabal2nix "foo" (inputs.haskell-multi-nix + /foo) { };
};
devShell = {
tools = hp: {
# Some buildTools are included by default. If you do not want them,
# set them to 'null' here.
ghcid = null;
# You can also add additional build tools.
fzf = pkgs.fzf;
};
hlsCheck.enable = true;
devShell.tools = hp: {
# Adding a tool should make it available in devshell.
fzf = pkgs.fzf;
};
};
# haskell-flake doesn't set the default package, but you can do it here.