Fix rubygems#2813: Ignore self dependency

lib/bundler/installer.rb

@@ -285,8 +285,7 @@ def install_in_parallel(size, standalone)
         { :name => spec.name, :post_install => message }
       }
       specs.each do |spec|
-        deps = spec.dependencies.select { |dep| dep.type != :development }
-        if deps.empty?
+        if ready_to_install?(spec, remains)
           worker_pool.enq spec.name
           enqueued[spec.name] = true
         end
@@ -301,8 +300,7 @@ def install_in_parallel(size, standalone)
         remains.keys.each do |name|
           next if enqueued[name]
           spec = name2spec[name]
-          deps = spec.dependencies.select { |dep| remains[dep.name] and dep.type != :development }
-          if deps.empty?
+          if ready_to_install?(spec, remains)
             worker_pool.enq name
             enqueued[name] = true
           end
@@ -312,5 +310,11 @@ def install_in_parallel(size, standalone)
     ensure
       worker_pool && worker_pool.stop
     end
+
+    def ready_to_install?(spec, remains)
+      spec.dependencies.none? do |dep|
+        remains[dep.name] && dep.type != :development && dep.name != spec.name
+      end
+    end
   end
 end

spec/realworld/parallel_install_spec.rb

@@ -12,12 +12,25 @@
     (0..1).each {|i| expect(out).to include("#{i}: ") }
 
     bundle "show activesupport"
-    expect(out).to match(/activesupport/)
+    expect(out).to match(%r{gems/activesupport})
 
     bundle "show faker"
     expect(out).to match(/faker/)
 
     bundle "config jobs"
     expect(out).to match(/: "2"/)
   end
+
+  it 'installs even with circular dependency' do
+    gemfile <<-G
+      source 'https://rubygems.org'
+      gem 'mongoid_auto_increment', "0.1.1"
+    G
+
+    bundle :install, :jobs => 2, :env => {"DEBUG" => "1"}
+    (0..1).each {|i| expect(out).to include("#{i}: ") }
+
+    bundle "show mongoid_auto_increment"
+    expect(out).to match(%r{gems/mongoid_auto_increment})
+  end
 end