9 files changed, 40 insertions, 8 deletions
diff --git a/.travis.yml b/.travis.yml
index b70d3892c1..af19cd41de 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -105,7 +105,7 @@ matrix:
       env:
         - "GEM=am,amo,aj"
     # Test with old (< 9.4.2) postgresql
-    - rvm: 2.4.0
+    - rvm: 2.4.1
       env:
         - "GEM=ar:postgresql"
       addons:
diff --git a/actioncable/test/client_test.rb b/actioncable/test/client_test.rb
index 98a114a5f4..4f7c585ba3 100644
--- a/actioncable/test/client_test.rb
+++ b/actioncable/test/client_test.rb
@@ -68,12 +68,23 @@ class ClientTest < ActionCable::TestCase
     server.min_threads = 1
     server.max_threads = 4
 
-    t = Thread.new { server.run.join }
-    yield port
+    thread = server.run
 
-  ensure
-    server.stop(true) if server
-    t.join if t
+    begin
+      yield port
+
+    ensure
+      server.stop
+
+      begin
+        thread.join
+      rescue RuntimeError => ex
+        raise unless ex.message =~ /can't modify frozen IOError/
+
+        # Work around https://bugs.ruby-lang.org/issues/13239
+        server.binder.close
+      end
+    end
   end
 
   class SyncClient
diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb
index 0276d41494..73518ca144 100644
--- a/activerecord/lib/active_record/railtie.rb
+++ b/activerecord/lib/active_record/railtie.rb
@@ -166,5 +166,13 @@ end_warning
       path = app.paths["db"].first
       config.watchable_files.concat ["#{path}/schema.rb", "#{path}/structure.sql"]
     end
+
+    initializer "active_record.clear_active_connections" do
+      config.after_initialize do
+        ActiveSupport.on_load(:active_record) do
+          clear_active_connections!
+        end
+      end
+    end
   end
 end
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index 34a3615070..5d24f5f5ca 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -224,7 +224,7 @@ module ActiveRecord
       fifth || raise_record_not_found_exception!
     end
 
-    # Find the forty-second record. Also known as accessing "the answer to life the universe and everything".
+    # Find the forty-second record. Also known as accessing "the reddit".
     # If no order is defined it will order by primary key.
     #
     #   Person.forty_two # returns the forty-second object fetched by SELECT * FROM people
diff --git a/activerecord/test/cases/dup_test.rb b/activerecord/test/cases/dup_test.rb
index 3821e0c949..000ed27efb 100644
--- a/activerecord/test/cases/dup_test.rb
+++ b/activerecord/test/cases/dup_test.rb
@@ -143,6 +143,8 @@ module ActiveRecord
     end
 
     def test_dup_without_primary_key
+      skip if current_adapter?(:OracleAdapter)
+
       klass = Class.new(ActiveRecord::Base) do
         self.table_name = "parrots_pirates"
       end
diff --git a/activerecord/test/cases/primary_keys_test.rb b/activerecord/test/cases/primary_keys_test.rb
index 12386635f6..5ded619716 100644
--- a/activerecord/test/cases/primary_keys_test.rb
+++ b/activerecord/test/cases/primary_keys_test.rb
@@ -183,6 +183,8 @@ class PrimaryKeysTest < ActiveRecord::TestCase
   end
 
   def test_create_without_primary_key_no_extra_query
+    skip if current_adapter?(:OracleAdapter)
+
     klass = Class.new(ActiveRecord::Base) do
       self.table_name = "dashboards"
     end
diff --git a/guides/assets/stylesheets/main.css b/guides/assets/stylesheets/main.css
index a1e4851833..b27776745a 100644
--- a/guides/assets/stylesheets/main.css
+++ b/guides/assets/stylesheets/main.css
@@ -294,6 +294,7 @@ a, a:link, a:visited {
 #mainCol a, #subCol a, #feature a {color: #980905;}
 #mainCol a code, #subCol a code, #feature a code {color: #980905;}
 
+#mainCol a.anchorlink, #mainCol a.anchorlink code {color: #333;}
 #mainCol a.anchorlink { text-decoration: none; }
 #mainCol a.anchorlink:hover { text-decoration: underline; }
 
diff --git a/railties/lib/rails/backtrace_cleaner.rb b/railties/lib/rails/backtrace_cleaner.rb
index 5c833e12ba..3bd18ebfb5 100644
--- a/railties/lib/rails/backtrace_cleaner.rb
+++ b/railties/lib/rails/backtrace_cleaner.rb
@@ -16,7 +16,7 @@ module Rails
       add_filter { |line| line.sub(DOT_SLASH, SLASH) } # for tests
 
       add_gem_filters
-      add_silencer { |line| line !~ APP_DIRS_PATTERN }
+      add_silencer { |line| !APP_DIRS_PATTERN.match?(line) }
     end
 
     private
diff --git a/railties/test/application/initializers/frameworks_test.rb b/railties/test/application/initializers/frameworks_test.rb
index 90927159dd..eb2c578f91 100644
--- a/railties/test/application/initializers/frameworks_test.rb
+++ b/railties/test/application/initializers/frameworks_test.rb
@@ -262,5 +262,13 @@ module ApplicationTests
         Rails.env = orig_rails_env if orig_rails_env
       end
     end
+
+    test "connections checked out during initialization are returned to the pool" do
+      app_file "config/initializers/active_record.rb", <<-RUBY
+        ActiveRecord::Base.connection
+      RUBY
+      require "#{app_path}/config/environment"
+      assert !ActiveRecord::Base.connection_pool.active_connection?
+    end
   end
 end