nixpkgs/pkgs/development/interpreters/ruby/fixes.nix

# The standard set of gems in nixpkgs including potential fixes.
#
# The gemset is derived from two points of entry:
# - An attrset describing a gem, including version, source and dependencies
#   This is just meta data, most probably automatically generated by a tool
#   like Bundix (https://github.com/aflatter/bundix).
#   {
#     name = "bundler";
#     version = "1.6.5";
#     sha256 = "1s4x0f5by9xs2y24jk6krq5ky7ffkzmxgr4z1nhdykdmpsi2zd0l";
#     dependencies = [ "rake" ];
#   }
# - An optional derivation that may override how the gem is built. For popular
#   gems that don't behave correctly, fixes are already provided in the form of
#   derivations.
#
# This seperates "what to build" (the exact gem versions) from "how to build"
# (to make gems behave if necessary).

{ lib, gemset, buildRubyGem, writeScript, ruby, libxml2, libxslt, python, stdenv
, which, postgresql, v8_3_16_14, clang }:

let
  const = x: y: x;
  v8 = v8_3_16_14;

  gems = lib.mapAttrs (name: attrs:
    if (lib.isDerivation attrs) then attrs
    else (instantiate name attrs)
  ) gemset;

  instantiate = (name: attrs:
    let
      gemPath = map (name: gems."${name}") (attrs.dependencies or []);
      fixedAttrs = attrs // (fixes."${name}" or const {}) attrs;
    in
      buildRubyGem (fixedAttrs // { name = "${name}-${attrs.version}"; inherit gemPath; })
  );

  fixes = {
    bundler = attrs: {
      dontPatchShebangs = 1;
    };

    libv8 = attrs: {
      buildFlags = [ "--with-system-v8" ];
      buildInputs = [ which v8 python ];
    };

    nokogiri = attrs: {
      buildFlags = [
        "--with-xml2-dir=${libxml2}"
        "--with-xml2-include=${libxml2}/include/libxml2"
        "--with-xslt-dir=${libxslt}"
        "--use-system-libraries"
      ];
    };

    therubyracer = attrs: {
      dontBuild = false;

      preInstall = ''
        addToSearchPath RUBYLIB "${gems.libv8}/gems/libv8-3.16.14.3/lib"
        addToSearchPath RUBYLIB "${gems.libv8}/gems/libv8-3.16.14.3/ext"
        ln -s ${clang}/bin/clang $TMPDIR/gcc
        ln -s ${clang}/bin/clang++ $TMPDIR/g++
        export PATH=$TMPDIR:$PATH
      '';

      postInstall = stdenv.lib.optionalString stdenv.isDarwin ''
        cat >> $out/nix-support/setup-hook <<EOF
          export DYLD_INSERT_LIBRARIES="$DYLD_INSERT_LIBRARIES''${!DYLD_INSERT_LIBRARIES:+:}${v8}/lib/libv8.dylib"
        EOF
      '';

      buildFlags = [
        "--with-v8-dir=${v8}" "--with-v8-include=${v8}/include"
        "--with-v8-lib=${v8}/lib"
      ];
    };
  };

in gems