Run the installer from ruby instead of using system(); otherwise we risk running the wrong ruby

gembag.rb

@@ -1,6 +1,7 @@
 #!/usr/bin/env ruby
 
-require "rubygems/package"
+require "rubygems/specification"
+require "rubygems/commands/install_command"
 
 gemspec = ARGV.shift
 
@@ -11,13 +12,21 @@ deps = [spec.development_dependencies, spec.runtime_dependencies].flatten
 target = "vendor/bundle/jruby/1.9/"
 
 deps.each do |dep|
-  cmd = "gem install --install-dir #{target} #{dep.name} -v '#{dep.requirement}'"
-  puts cmd
-  system(cmd)
+  #cmd = "gem install --install-dir #{target} #{dep.name} -v '#{dep.requirement}'"
+  installer = Gem::Commands::InstallCommand.new
+  installer.options[:generate_rdoc] = false
+  installer.options[:generate_ri] = false
+  installer.options[:version] = dep.requirement
+  installer.options[:args] = [dep.name]
+  begin
+    installer.execute
+  rescue Gem::SystemExitException => e
+    if e.exit_code != 0
+      puts "Installation of #{dep.to_s} failed"
+      raise
+    end
+  end
 end
 
-#specs_and_sources, errors = Gem::SpecFetcher.fetcher.fetch_with_errors(deps.first, true, true, false)
-#require "pry"; binding.pry
-