This fix doesn't actually fix the cabal bug (see #16357), but it does
cause other bugs (see #20476)
Fixes #20476
This reverts commit b89fa5fd5c, reversing
changes made to e4b146b041.
This reverts commit ec8b816154. The change told
the Cabal build system to use the hash-part of $out as the internal identifier
for the library it's building (rather than generating such an ID itself). While
a good idea in theory, this choice had an unfortunate side-effect: When Cabal
links libraries X, Y, and Z into an executable, then the generated binary
contains their respective IDs. Now, Nix finds those strings and treats them as
an indication that there is a *run-time dependency* on the corresponding store
paths. This means that the generated executable will always depend on the store
paths of all the Haskell libraries that went into it, even when linked
statically.
This commit fixes a problem that occurs with externally linked haskell
libraries on Darwin. It does this by adding the libraries to the
--extra-lib-dirs flag and the DYLD_LIBRARY_PATH environment variable.
Without this patch, attempts to install at least some of the packages
that start to use setupHaskellDepends (mostly gtk-related packages)
results in collisions:
building path(s) ‘/nix/store/63k5smns43f5r2ad8wcc242x0gwd70m3-ghc-8.0.1’
collision between `/nix/store/k18i1nm5hgnb82y9w2g9hmlwhk3szjld-ghc-8.0.1/lib/ghc-8.0.1/Cabal-1.24.0.0/Distribution/Compat/Binary.dyn_hi' and `/nix/store/0rwhbwsg9kmywgbrib2bs29p2hmi80za-Cabal-1.24.0.0/lib/ghc-8.0.1/Cabal-1.24.0.0/Distribution/Compat/Binary.dyn_hi'
builder for ‘/nix/store/vrjkfpm8sb96m9i5k74h8vn0rwddgy4v-ghc-8.0.1.drv’ failed with exit code 25
This would appear to me to be a consequence of setupHaskellDepends
entries being added to propagateBuildInputs. It is sufficient in the
cases I'm familiar with (taffyBar), and I think correct, to simply add
it to the otherBuildInputs.
hydraPlatforms now defaults to the value of meta.platforms rather than
defaulting to ghc.meta.hydraPlatforms. This solution is, in fact, still
sub-optimal. See https://github.com/NixOS/nixpkgs/issues/9608 for further
details.
A derivation of the Hackage package "foo" is called "haskell-foo" if it is a
library, but only "foo" if it is an executable (without a library). This
distinction used to be fine when Haskell packages where visible to operations
like "nix-env -qa" or "nix-env -i", but after our switch to Haskell NG it has
no more purpose. Consequently, this patch removes the name prefix from all
Haskell packages -- every Haskell package is now called exactly like it's
called on Hackage.
Closes https://github.com/NixOS/nixpkgs/pull/9538.
This also:
1 Builds Setup.hs with ghcjs, which (among other things) defines
__GHCJS__ and ghcjs_HOST_OS during pre-processing.
2 Fixes ghc-paths to point at ghcjs and use NIX_GHCJS_* env-vars.
3 Boots ghcjs into $prefix/lib/$compiler.
hydra.nixos.org serves broken binaries because of our favorite non-deterministic
package IDs in GHC bug. :-( Re-building everything from scratch seems like the
easiest way to recover.
We disabled this to prevent users from accidentally running nix-build on
an 'env' attribute, but in fact the ability to use those in combination
with "nix-shell -p" is quite useful, so the restriction is lifted.
