Exec: add option for ruby 1.9 FD behavior for 2.0

Ruby 2.0 changed the behavior of file descriptors when doing a Kernel.exec.
Where in 1.9 it wouldn't automatically close non-standard file descriptors
when doing a Kernel.exec, in 2.0 the default is to close them.

Issue #2628

2 files changed, 38 insertions, 0 deletions

diff --git a/lib/bundler/cli.rb b/lib/bundler/cli.rb
index a1c54cf4fb..d180cade61 100644
--- a/lib/bundler/cli.rb
+++ b/lib/bundler/cli.rb
@@ -513,6 +513,7 @@ module Bundler
     map %w(pack) => :package
 
     desc "exec", "Run the command in context of the bundle"
+    method_options :keep_file_descriptors => :boolean
     long_desc <<-D
       Exec runs a command, providing it access to the gems in the bundle. While using
       bundle exec you can require and call the bundled gems as if they were installed
@@ -523,6 +524,12 @@ module Bundler
       Bundler.load.setup_environment
 
       begin
+        # Ruby 2.0 changed the default file descriptor
+        # behavior for #exec, this option forces 1.9 behavior
+        if RUBY_VERSION >= "2.0" && options.keep_file_descriptors?
+          args << { :close_others => false }
+        end
+
         # Run
         Kernel.exec(*args)
       rescue Errno::EACCES
diff --git a/spec/commands/exec_spec.rb b/spec/commands/exec_spec.rb
index ed03e2b0a9..3a932adcbc 100644
--- a/spec/commands/exec_spec.rb
+++ b/spec/commands/exec_spec.rb
@@ -57,6 +57,37 @@ describe "bundle exec" do
     expect(out).to eq("--verbose")
   end
 
+  it "handles --keep-file-descriptors" do
+    require 'tempfile'
+
+    bundle_bin = File.expand_path('../../../bin/bundle', __FILE__)
+
+    command = Tempfile.new("io-test")
+    command.sync = true
+    command.write <<-G
+      if ARGV[0]
+        IO.for_fd(ARGV[0].to_i)
+      else
+        require 'tempfile'
+        io = Tempfile.new("io-test-fd")
+        args = %W[#{Gem.ruby} -I#{lib} #{bundle_bin} exec --keep-file-descriptors #{Gem.ruby} #{command.path} \#{io.to_i}]
+        args << { io.to_i => io } if RUBY_VERSION >= "2.0"
+        exec(*args)
+      end
+    G
+
+    install_gemfile ''
+    sys_exec("#{Gem.ruby} #{command.path}")
+    expect(out).to eq("")
+    expect(err).to eq("")
+  end
+
+  it "accepts --keep-file-descriptors" do
+    install_gemfile ''
+    bundle "exec --keep-file-descriptors echo foobar"
+    expect(out).to eq("foobar")
+  end
+
   it "can run a command named --verbose" do
     install_gemfile 'gem "rack"'
     File.open("--verbose", 'w') do |f|