Add pkgs.haskell.lib.packagesFromDirectory utility
#42923
Conversation
This adds a `readDirectory` utility that can be used to "slurp" a directory
full of `cabal2nix`-generated files and transform them into a Haskell package
override set. The main use of this is so that users don't have to write:
```
{ overrides = self: super: {
foo = self.callPackage ./path/to/foo.nix { };
bar = self.callPackage ./path/to/bar.nix { };
...
};
}
```
Instead, they can write:
```
{ overrides = pkgs.haskell.lib.readDirectory ./path/to;
}
```
This is a an alternative to `packageSourceOverrides` which primarily addresses
the following use cases:
* The desired package is not yet available in `all-cabal-hashes` (perhaps the
user is pinned to an older revision of `nixpkgs`)
* The default `cabal2nix` invocation used by `packageSourceOverrides`
does not use the desired `cabal2nix` flags
* The user wants to avoid the use of import-from-derivation
|
It'd be nice to ignore missing If you make the first parameter an attrset pattern, such functionality can be added in the future. Future example: |
|
@roberth: It's lazy, so it will only attempt to read files if you try to access the corresponding attribute and ignore any other files However, I agree that it should probably take an attribute set as an argument for ease of extension later |
|
@Gabriel439 good point. I'm using a little hack to collect self-defined attributes in my overlay for |
... as suggested by @roberth
|
Not sure if |
... as suggested by @roberth
roberth
changed the title
pkgs.haskell.lib.readDirectory utilitypkgs.haskell.lib.packagesFromDirectory utility
Add `...` for less painful downgrades in the future
|
I've added LGTM. Will merge in a couple of days unless anyone objects. |
Motivation for this change
This adds a
readDirectoryutility that can be used to "slurp" a directoryfull of
cabal2nix-generated files and transform them into a Haskell packageoverride set. The main use of this is so that users don't have to write:
Instead, they can write:
This is a an alternative to
packageSourceOverrideswhich primarily addressesthe following use cases:
all-cabal-hashes(perhaps theuser is pinned to an older revision of
nixpkgs)cabal2nixinvocation used bypackageSourceOverridesdoes not use the desired
cabal2nixflagsThings done
sandboxinnix.confon non-NixOS)nix-shell -p nox --run "nox-review wip"./result/bin/)nix path-info -Sbefore and after)