Add Bundler.system_bindir, defaulted to Gem.bindir

This allows users to tell Bundler where to put the binstubs for system gems, much like the -n option in ~/.gemrc for Rubygems. If you set one, it probably makes sense to set the other. If you don't set system_bindir, though, Bundler will install system binstubs into Gem.bindir, regardless of what Rubygems does.

refs #1417

lib/bundler.rb

@@ -219,13 +219,22 @@ def default_lockfile
       SharedHelpers.default_lockfile
     end
 
+    def system_bindir
+      # Gem.bindir doesn't always return the location that Rubygems will install
+      # system binaries. If you add a '-n foo' option to your .gemrc, Rubygems will
+      # install binstubs there instead. Unfortunately, Rubygems doesn't expose
+      # that directory at all, so rather than parse .gemrc ourselves, we allow
+      # the directory to be set as well, via `bundle config bindir foo`.
+      Bundler.settings[:system_bindir] || Gem.bindir
+    end
+
     def requires_sudo?
       return @requires_sudo if defined?(@checked_for_sudo)
 
       path = bundle_path
       path = path.parent until path.exist?
       sudo_present = !(`which sudo` rescue '').empty?
-      bin_dir = Pathname.new(Bundler.rubygems.gem_bindir)
+      bin_dir = Pathname.new(Bundler.system_bindir)
       bin_dir = bin_dir.parent until bin_dir.exist?
 
       @checked_for_sudo = true

lib/bundler/rubygems_integration.rb

@@ -50,12 +50,7 @@ def gem_dir
     end
 
     def gem_bindir
-      # We use Gem.dir/bin because on OS X, Gem.bindir is hardcoded to return
-      # /usr/bin, a directory owned by root. Users who chown Gem.dir need bins
-      # to be installed where they have permissions. Furthermore, the official
-      # solution to change the bindir is adding -n to .gemrc, but Rubygems does
-      # not honor the -n option in either Gem.bindir or Installer.new.bindir.
-      File.join Gem.dir, "bin"
+      Gem.bindir
     end
 
     def user_home

lib/bundler/source.rb

@@ -86,7 +86,7 @@ def install(spec)
             :ignore_dependencies => true,
             :wrappers            => true,
             :env_shebang         => true,
-            :bin_dir => "#{install_path}/bin"
+            :bin_dir             => Bundler.system_bindir
           ).install
         end
 
@@ -100,8 +100,8 @@ def install(spec)
           Bundler.sudo "cp -R #{Bundler.tmp}/gems/#{spec.full_name} #{Bundler.rubygems.gem_dir}/gems/"
           Bundler.sudo "cp -R #{Bundler.tmp}/specifications/#{spec.full_name}.gemspec #{Bundler.rubygems.gem_dir}/specifications/"
           spec.executables.each do |exe|
-            Bundler.sudo "mkdir -p #{Bundler.rubygems.gem_bindir}"
-            Bundler.sudo "cp -R #{Bundler.tmp}/bin/#{exe} #{Bundler.rubygems.gem_bindir}"
+            Bundler.sudo "mkdir -p #{Bundler.system_bindir}"
+            Bundler.sudo "cp -R #{Bundler.tmp}/bin/#{exe} #{Bundler.system_bindir}"
           end
         end
 

spec/install/gems/simple_case_spec.rb

@@ -733,22 +733,22 @@ def set_bundle_path(type, location)
     end
   end
 
-  describe "when Gem.bindir is hardcoded to a root-owned directory" do
-    # On OS X, Gem.bindir is hardcoded to /usr/bin. :(
-    it "installs binstubs into Gem.dir+'/bin' instead" do
+  describe "when system_bindir is set" do
+    # On OS X, Gem.bindir defaults to /usr/bin, so system_bindir is useful if
+    # you want to avoid sudo installs for system gems with OS X's default ruby
+    it "overrides Gem.bindir" do
       Pathname.new("/usr/bin").should_not be_writable
-
       gemfile <<-G
         require 'rubygems'
-        def Gem.bindir(dir=Gem.dir); "/usr/bin"; end
-
+        def Gem.bindir; "/usr/bin"; end
         source "file://#{gem_repo1}"
         gem "rack"
       G
 
+      config "BUNDLE_SYSTEM_BINDIR" => system_gem_path('altbin').to_s
       bundle :install
       should_be_installed "rack 1.0.0"
-      system_gem_path("bin/rackup").should exist
+      system_gem_path("altbin/rackup").should exist
     end
   end