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
This works by extracting out some logic from generic-builder.nix to
make it possible to get at the relevant information by overriding
mkDerivation for the haskell package.
This reverts commit dfb0f25484, reversing
changes made to 7f8ff02437. These changes broke
the ghcWithPackages wrapper:
nix-shell -p "haskellPackages.ghcWithPackages (ps: [ps.mtl])" --run "ghc-pkg list mtl"
/nix/store/szz84j5k1dy3jdashis6ws28d8l8zxxb-ghc-8.0.2-with-packages/lib/ghc-8.0.2/package.conf.d
(no packages)
- The haskell lib is very close to not relying on Nixpkgs. I think
this is good---simpler to think about and matches Nixpkgs's lib.
- The haskell lib is only imported once
- stdenv is exposed more shallowly so it can be overriden more easily.
I'll eventually use this on Darwin to avoid the Sierra shared
library problems (unless changes are to be made system-wide).
Closes https://github.com/NixOS/nixpkgs/pull/27840.
A function is added to enable the generation of a HPC report. For example:
pkgs.haskell.lib.doCoverage drv
will create a HPC report of the Haskell package drv in the directory:
$out/share/hpc
Closes https://github.com/NixOS/nixpkgs/pull/22797/files.
As per the recommendation by @Mathnerd314, this change seems to work
with the testing I did.
It makes sense to me why it works, but I think it's in an important
enough place that someone with much deeper knowledge of Haskell
infrastructure in Nixpkgs should give it a really heavy review.
I also consolidated all the overrideCabal definitions (there were two)
into a single definition in haskell-modules/lib.nix.
-split-sections replaced -split-objs with following upsides:
1) -split-objs adds considerable overhead to compile time
2) combined with stripping, it causes issues when cross-compiling
For upstream see https://ghc.haskell.org/trac/ghc/ticket/8405
This is supported only for Linux/Windows using ld linker.
GHC master also turns on -split-sections by default.
Example using stack:
Without splitting
$ du /nix/store/5paayhibayr73zqfaj458g4k4mv108jn-stack-1.3.2
4 /nix/store/5paayhibayr73zqfaj458g4k4mv108jn-stack-1.3.2/share/bash-completion/completions
4 /nix/store/5paayhibayr73zqfaj458g4k4mv108jn-stack-1.3.2/share/bash-completion
4 /nix/store/5paayhibayr73zqfaj458g4k4mv108jn-stack-1.3.2/share
23416 /nix/store/5paayhibayr73zqfaj458g4k4mv108jn-stack-1.3.2/bin
23420 /nix/store/5paayhibayr73zqfaj458g4k4mv108jn-stack-1.3.2
With -split-objs
$ du /nix/store/fypymm529adpx71gdzm0851xz42wdbz0-stack-1.3.2
20632 /nix/store/fypymm529adpx71gdzm0851xz42wdbz0-stack-1.3.2/bin
4 /nix/store/fypymm529adpx71gdzm0851xz42wdbz0-stack-1.3.2/share/bash-completion/completions
4 /nix/store/fypymm529adpx71gdzm0851xz42wdbz0-stack-1.3.2/share/bash-completion
4 /nix/store/fypymm529adpx71gdzm0851xz42wdbz0-stack-1.3.2/share
20636 /nix/store/fypymm529adpx71gdzm0851xz42wdbz0-stack-1.3.2
With -split-sections
$ du /nix/store/40l6krinx1zx41lr87c4m12hxj4ldf3x-stack-1.3.2
4 /nix/store/40l6krinx1zx41lr87c4m12hxj4ldf3x-stack-1.3.2/share/bash-completion/completions
4 /nix/store/40l6krinx1zx41lr87c4m12hxj4ldf3x-stack-1.3.2/share/bash-completion
4 /nix/store/40l6krinx1zx41lr87c4m12hxj4ldf3x-stack-1.3.2/share
20672 /nix/store/40l6krinx1zx41lr87c4m12hxj4ldf3x-stack-1.3.2/bin
20676 /nix/store/40l6krinx1zx41lr87c4m12hxj4ldf3x-stack-1.3.2
Note: you currently need following overrides to build stack on 802:
vector-algorithms = dontCheck super.vector-algorithms;
path-io = doJailbreak super.path-io;
stack = doJailbreak super.stack;
Note: Should also work on GHC 8.0.1, but I'm being careful here.
We could backport later on.
Before:
```
error: getting status of
‘/home/user/nixpkgs/pkgs/development/development/haskell-modules/generic-stack-builder.nix’:
No such file or directory
```
