* There now is full support for building Haskell packages as shared libraries
for GHC versions 7.4.2 or later. The Cabal builder recognizes the following
attributes:
- enableSharedLibraries configures Cabal to build of shared libraries in
addition to static ones. This option requires that all dependencies of
the package have been compiled for use in shared libraries, too.
- enableSharedExecutables configures Cabal to prefer shared libraries when
linking executables.
The default values for these attributes are arguments to the haskellPackages
expression.
* Haskell builds now run in a LANG="en_US.UTF-8" environment to avoid plenty
of build and test suite errors. Without this setting, GHC seems unable to
deal with the UTF-8 character encoding that's generally considered standard
in the Haskell world.
* The Cabal builder supports a new attribute 'testTarget' to specify the exact
set of tests to be run during the check phase.
* The ghc-wrapper attribute ghcVersion has been removed. Instead, we use the
ghc.version attribute, which exists in unwrapped GHC derivations, too.
The previous implementation used the following tying-the-knot trickery to
override 'doCheck' to false for the given build:
cabalNoTest = {
mkDerivation = x: rec {
final = self.cabal.mkDerivation (self: (x final) // { doCheck = false; });
}.final;
};
That seemed to work, but for some reason it caused trouble with some builds --
not all -- that use jailbreakCabal. The problem was the 'stdenv' attribute
couldn't be evaluated properly anymore:
$ nix-build ~/pkgs/top-level/release-haskell.nix -A optparseApplicative.ghc6104.x86_64-linux --show-trace
error: while evaluating the attribute `drvPath' at `/nix/store/qkj5cxknwspz8ak0ganm97zfr2bhksgn-nix-1.5.2pre3082_2398417/share/nix/corepkgs/derivation.nix:19:9':
while evaluating the builtin function `derivationStrict':
while instantiating the derivation named `haskell-optparse-applicative-ghc6.10.4-0.5.2.1' at `/home/simons/.nix-defexpr/pkgs/build-support/cabal/default.nix:40:13':
while evaluating the derivation attribute `configurePhase' at `/home/simons/.nix-defexpr/pkgs/build-support/cabal/default.nix:107:13':
while evaluating the function at `/home/simons/.nix-defexpr/pkgs/lib/strings.nix:55:26':
while evaluating the attribute `outPath' at `/nix/store/qkj5cxknwspz8ak0ganm97zfr2bhksgn-nix-1.5.2pre3082_2398417/share/nix/corepkgs/derivation.nix:18:9':
while evaluating the builtin function `getAttr':
while evaluating the builtin function `derivationStrict':
while instantiating the derivation named `jailbreak-cabal-1.1' at `/home/simons/.nix-defexpr/pkgs/build-support/cabal/default.nix:40:13':
while evaluating the derivation attribute `nativeBuildInputs' at `/home/simons/.nix-defexpr/pkgs/stdenv/generic/default.nix:76:17':
while evaluating the function at `/home/simons/.nix-defexpr/pkgs/lib/lists.nix:135:21':
while evaluating the attribute `buildInputs' at `/home/simons/.nix-defexpr/pkgs/build-support/cabal/default.nix:22:17':
while evaluating the builtin function `filter':
while evaluating the function at `/home/simons/.nix-defexpr/pkgs/build-support/cabal/default.nix:22:60':
while evaluating the function at `/home/simons/.nix-defexpr/pkgs/top-level/haskell-packages.nix:119:17':
while evaluating the function at `/home/simons/.nix-defexpr/pkgs/lib/customisation.nix:61:22':
while evaluating the function at `/home/simons/.nix-defexpr/pkgs/lib/customisation.nix:56:24':
while evaluating the builtin function `isAttrs':
while evaluating the function at `/home/simons/.nix-defexpr/pkgs/development/libraries/haskell/Cabal/1.14.0.nix:1:1':
while evaluating the function at `/home/simons/.nix-defexpr/pkgs/top-level/haskell-packages.nix:113:20':
while evaluating the attribute `final' at `/home/simons/.nix-defexpr/pkgs/top-level/haskell-packages.nix:114:7':
while evaluating the function at `/home/simons/.nix-defexpr/pkgs/build-support/cabal/default.nix:9:5':
while evaluating the function at `/home/simons/.nix-defexpr/pkgs/stdenv/generic/default.nix:51:24':
while evaluating the attribute `meta.license' at `/home/simons/.nix-defexpr/pkgs/development/libraries/haskell/Cabal/1.14.0.nix:17:5':
infinite recursion encountered
I tried to figure out why this happens, but eventually gave up. The new
implementation passes an argument called 'enableCheckPhase' to the Cabal
builder, which determines whether the user-specified doCheck value has any
effect or not. Now, a normal override can be used to disable unit testing.
According to <http://hackage.haskell.org/trac/ghc/ticket/4013>, this
feature won't work with XCode versions older than 3.2.
This means that Mac users will have considerably larger binaries because
some build-time dependencies (such as HTTP) will be mis-detected as
run-time dependencies.
This patch configures all Cabal builds with '--enable-split-objs' unless the
Nix expression explicitly sets "enableSplitObjs = false". The Cabal manual [1]
describes this option as follows:
| The GHC -split-objs reduces the final size of the executables that use the
| library by allowing them to link with only the bits that they use rather
| than the entire library. The downside is that building the library takes
| longer and uses considerably more memory.
One immediate benefit of this change is that the 'darcs' closure defined in the
top-level no longer refers to GHC. The same is probably true with other
executable packages.
[1] http://www.haskell.org/cabal/users-guide/installing-packages.html#setup-configure
Jailbreaks-cabal allows Nixpkgs maintainers to quick-fix builds of packages
that over-specify their version requirements by removing the version
restrictions of all dependencies from the Cabal file. Set
jailbreak = true
in the build expression to activate this feature.
