Replaced ActiveSupport::Concurrency::Latch with concurrent-ruby.

The concurrent-ruby gem is a toolset containing many concurrency
utilities. Many of these utilities include runtime-specific
optimizations when possible. Rather than clutter the Rails codebase with
concurrency utilities separate from the core task, such tools can be
superseded by similar tools in the more specialized gem. This commit
replaces `ActiveSupport::Concurrency::Latch` with
`Concurrent::CountDownLatch`, which is functionally equivalent.

Author: jdantonio

Gemfile.lock

@@ -64,6 +64,7 @@ PATH
     actionpack (5.0.0.alpha)
       actionview (= 5.0.0.alpha)
       activesupport (= 5.0.0.alpha)
+      concurrent-ruby (~> 0.9.0)
       rack (~> 1.6)
       rack-test (~> 0.6.3)
       rails-dom-testing (~> 1.0, >= 1.0.5)
@@ -85,6 +86,7 @@ PATH
       activesupport (= 5.0.0.alpha)
       arel (= 7.0.0.alpha)
     activesupport (5.0.0.alpha)
+      concurrent-ruby (~> 0.9.0)
       i18n (~> 0.7)
       json (~> 1.7, >= 1.7.7)
       minitest (~> 5.1)
@@ -135,6 +137,7 @@ GEM
       execjs
     coffee-script-source (1.9.0)
     columnize (0.9.0)
+    concurrent-ruby (0.9.0)
     connection_pool (2.1.1)
     dalli (2.7.2)
     dante (0.1.5)

actionpack/CHANGELOG.md

@@ -1,3 +1,8 @@
+*   Replaced `ActiveSupport::Concurrency::Latch` with `Concurrent::CountDownLatch`
+    from the concurrent-ruby gem.
+
+    *Jerry D'Antonio*
+
 *   Add ability to filter parameters based on parent keys.
 
         # matches {credit_card: {code: "xxxx"}}

actionpack/actionpack.gemspec

@@ -26,6 +26,7 @@ Gem::Specification.new do |s|
   s.add_dependency 'rails-html-sanitizer', '~> 1.0', '>= 1.0.2'
   s.add_dependency 'rails-dom-testing', '~> 1.0', '>= 1.0.5'
   s.add_dependency 'actionview', version
+  s.add_dependency 'concurrent-ruby', '~> 0.9.0'
 
   s.add_development_dependency 'activemodel', version
 end

actionpack/test/controller/live_stream_test.rb

@@ -1,5 +1,5 @@
 require 'abstract_unit'
-require 'active_support/concurrency/latch'
+require 'concurrent/atomics'
 Thread.abort_on_exception = true
 
 module ActionController
@@ -145,7 +145,7 @@ def blocking_stream
         response.headers['Content-Type'] = 'text/event-stream'
         %w{ hello world }.each do |word|
           response.stream.write word
-          latch.await
+          latch.wait
         end
         response.stream.close
       end
@@ -212,7 +212,7 @@ def overfill_buffer_and_die
         # .. plus one more, because the #each frees up a slot:
         response.stream.write '.'
 
-        latch.release
+        latch.count_down
 
         # This write will block, and eventually raise
         response.stream.write 'x'
@@ -233,7 +233,7 @@ def ignore_client_disconnect
         end
 
         logger.info 'Work complete'
-        latch.release
+        latch.count_down
       end
     end
 
@@ -278,7 +278,7 @@ def test_write_to_stream
     def test_async_stream
       rubinius_skip "https://github.com/rubinius/rubinius/issues/2934"
 
-      @controller.latch = ActiveSupport::Concurrency::Latch.new
+      @controller.latch = Concurrent::CountDownLatch.new
       parts             = ['hello', 'world']
 
       @controller.request  = @request
@@ -289,8 +289,8 @@ def test_async_stream
         resp.stream.each do |part|
           assert_equal parts.shift, part
           ol = @controller.latch
-          @controller.latch = ActiveSupport::Concurrency::Latch.new
-          ol.release
+          @controller.latch = Concurrent::CountDownLatch.new
+          ol.count_down
         end
       }
 
@@ -300,23 +300,23 @@ def test_async_stream
     end
 
     def test_abort_with_full_buffer
-      @controller.latch = ActiveSupport::Concurrency::Latch.new
+      @controller.latch = Concurrent::CountDownLatch.new
 
       @request.parameters[:format] = 'plain'
       @controller.request  = @request
       @controller.response = @response
 
-      got_error = ActiveSupport::Concurrency::Latch.new
+      got_error = Concurrent::CountDownLatch.new
       @response.stream.on_error do
         ActionController::Base.logger.warn 'Error while streaming'
-        got_error.release
+        got_error.count_down
       end
 
       t = Thread.new(@response) { |resp|
         resp.await_commit
         _, _, body = resp.to_a
         body.each do |part|
-          @controller.latch.await
+          @controller.latch.wait
           body.close
           break
         end
@@ -325,13 +325,13 @@ def test_abort_with_full_buffer
       capture_log_output do |output|
         @controller.process :overfill_buffer_and_die
         t.join
-        got_error.await
+        got_error.wait
         assert_match 'Error while streaming', output.rewind && output.read
       end
     end
 
     def test_ignore_client_disconnect
-      @controller.latch = ActiveSupport::Concurrency::Latch.new
+      @controller.latch = Concurrent::CountDownLatch.new
 
       @controller.request  = @request
       @controller.response = @response
@@ -349,7 +349,7 @@ def test_ignore_client_disconnect
         @controller.process :ignore_client_disconnect
         t.join
         Timeout.timeout(3) do
-          @controller.latch.await
+          @controller.latch.wait
         end
         assert_match 'Work complete', output.rewind && output.read
       end

actionpack/test/dispatch/live_response_test.rb

@@ -1,5 +1,5 @@
 require 'abstract_unit'
-require 'active_support/concurrency/latch'
+require 'concurrent/atomics'
 
 module ActionController
   module Live
@@ -27,18 +27,18 @@ def self.default_headers
       end
 
       def test_parallel
-        latch = ActiveSupport::Concurrency::Latch.new
+        latch = Concurrent::CountDownLatch.new
 
         t = Thread.new {
           @response.stream.write 'foo'
-          latch.await
+          latch.wait
           @response.stream.close
         }
 
         @response.await_commit
         @response.each do |part|
           assert_equal 'foo', part
-          latch.release
+          latch.count_down
         end
         assert t.join
       end
@@ -62,15 +62,15 @@ def test_content_length_is_removed
 
       def test_headers_cannot_be_written_after_webserver_reads
         @response.stream.write 'omg'
-        latch = ActiveSupport::Concurrency::Latch.new
+        latch = Concurrent::CountDownLatch.new
 
         t = Thread.new {
           @response.stream.each do |chunk|
-            latch.release
+            latch.count_down
           end
         }
 
-        latch.await
+        latch.wait
         assert @response.headers.frozen?
         e = assert_raises(ActionDispatch::IllegalStateError) do
           @response.headers['Content-Length'] = "zomg"

activerecord/CHANGELOG.md

@@ -1,3 +1,8 @@
+*   Replaced `ActiveSupport::Concurrency::Latch` with `Concurrent::CountDownLatch`
+    from the concurrent-ruby gem.
+
+    *Jerry D'Antonio*
+
 *   Fix through associations using scopes having the scope merged multiple
     times.
 

activerecord/test/cases/base_test.rb

@@ -1,7 +1,6 @@
 # -*- coding: utf-8 -*-
 
 require "cases/helper"
-require 'active_support/concurrency/latch'
 require 'models/post'
 require 'models/author'
 require 'models/topic'
@@ -29,6 +28,7 @@
 require 'models/car'
 require 'models/bulb'
 require 'rexml/document'
+require 'concurrent/atomics'
 
 class FirstAbstractClass < ActiveRecord::Base
   self.abstract_class = true
@@ -1506,20 +1506,20 @@ def test_default_values_are_deeply_dupped
     orig_handler = klass.connection_handler
     new_handler = ActiveRecord::ConnectionAdapters::ConnectionHandler.new
     after_handler = nil
-    latch1 = ActiveSupport::Concurrency::Latch.new
-    latch2 = ActiveSupport::Concurrency::Latch.new
+    latch1 = Concurrent::CountDownLatch.new
+    latch2 = Concurrent::CountDownLatch.new
 
     t = Thread.new do
       klass.connection_handler = new_handler
-      latch1.release
-      latch2.await
+      latch1.count_down
+      latch2.wait
       after_handler = klass.connection_handler
     end
 
-    latch1.await
+    latch1.wait
 
     klass.connection_handler = orig_handler
-    latch2.release
+    latch2.count_down
     t.join
 
     assert_equal after_handler, new_handler

activerecord/test/cases/connection_pool_test.rb

@@ -1,5 +1,5 @@
 require "cases/helper"
-require 'active_support/concurrency/latch'
+require 'concurrent/atomics'
 
 module ActiveRecord
   module ConnectionAdapters
@@ -133,15 +133,15 @@ def test_reap_and_active
       end
 
       def test_reap_inactive
-        ready = ActiveSupport::Concurrency::Latch.new
+        ready = Concurrent::CountDownLatch.new
         @pool.checkout
         child = Thread.new do
           @pool.checkout
           @pool.checkout
-          ready.release
+          ready.count_down
           Thread.stop
         end
-        ready.await
+        ready.wait
 
         assert_equal 3, active_connections(@pool).size
 
@@ -360,13 +360,13 @@ def test_pool_sets_connection_schema_cache
       def test_concurrent_connection_establishment
         assert_operator @pool.connections.size, :<=, 1
 
-        all_threads_in_new_connection = ActiveSupport::Concurrency::Latch.new(@pool.size - @pool.connections.size)
-        all_go                        = ActiveSupport::Concurrency::Latch.new
+        all_threads_in_new_connection = Concurrent::CountDownLatch.new(@pool.size - @pool.connections.size)
+        all_go                        = Concurrent::CountDownLatch.new
 
         @pool.singleton_class.class_eval do
           define_method(:new_connection) do
-            all_threads_in_new_connection.release
-            all_go.await
+            all_threads_in_new_connection.count_down
+            all_go.wait
             super()
           end
         end
@@ -381,14 +381,14 @@ def test_concurrent_connection_establishment
             # the kernel of the whole test is here, everything else is just scaffolding,
             # this latch will not be released unless conn. pool allows for concurrent
             # connection creation
-            all_threads_in_new_connection.await
+            all_threads_in_new_connection.wait
           end
         rescue Timeout::Error
           flunk 'pool unable to establish connections concurrently or implementation has ' <<
                 'changed, this test then needs to patch a different :new_connection method'
         ensure
           # clean up the threads
-          all_go.release
+          all_go.count_down
           connecting_threads.map(&:join)
         end
       end
@@ -441,11 +441,11 @@ def test_disconnect_and_clear_reloadable_connections_are_able_to_preempt_other_w
         with_single_connection_pool do |pool|
           [:disconnect, :disconnect!, :clear_reloadable_connections, :clear_reloadable_connections!].each do |group_action_method|
             conn               = pool.connection # drain the only available connection
-            second_thread_done = ActiveSupport::Concurrency::Latch.new
+            second_thread_done = Concurrent::CountDownLatch.new
 
             # create a first_thread and let it get into the FIFO queue first
             first_thread = Thread.new do
-              pool.with_connection { second_thread_done.await }
+              pool.with_connection { second_thread_done.wait }
             end
 
             # wait for first_thread to get in queue
@@ -456,7 +456,7 @@ def test_disconnect_and_clear_reloadable_connections_are_able_to_preempt_other_w
             # first_thread when a connection is made available
             second_thread = Thread.new do
               pool.send(group_action_method)
-              second_thread_done.release
+              second_thread_done.count_down
             end
 
             # wait for second_thread to get in queue
@@ -471,7 +471,7 @@ def test_disconnect_and_clear_reloadable_connections_are_able_to_preempt_other_w
             failed = true unless second_thread.join(2)
 
             #--- post test clean up start
-            second_thread_done.release if failed
+            second_thread_done.count_down if failed
 
             # after `pool.disconnect()` the first thread will be left stuck in queue, no need to wait for
             # it to timeout with ConnectionTimeoutError

activesupport/CHANGELOG.md

@@ -1,3 +1,8 @@
+*   Removed `ActiveSupport::Concurrency::Latch`, superseded by `Concurrent::CountDownLatch`
+    from the concurrent-ruby gem.
+
+    *Jerry D'Antonio*
+
 *   Fix not calling `#default` on `HashWithIndifferentAccess#to_hash` when only
     `default_proc` is set, which could raise.
 

activesupport/activesupport.gemspec

@@ -25,4 +25,5 @@ Gem::Specification.new do |s|
   s.add_dependency 'tzinfo',     '~> 1.1'
   s.add_dependency 'minitest',   '~> 5.1'
   s.add_dependency 'thread_safe','~> 0.3', '>= 0.3.4'
+  s.add_dependency 'concurrent-ruby', '~> 0.9.0'
 end