Merge branch 'master' into set_binds

* master: (2794 commits)
  doc, API example on how to use `Model#exists?` with multiple IDs. [ci skip]
  Restore DATABASE_URL even if it's nil in connection_handler test
  [ci skip] - error_messages_for has been deprecated since 2.3.8 - lets reduce any confusion for users
  Ensure Active Record connection consistency
  Revert "ask the fixture set for the sql statements"
  Check `respond_to` before delegation due to: https://github.com/ruby/ruby/commit/d781caaf313b8649948c107bba277e5ad7307314
  Adding Hash#compact and Hash#compact! methods
  MySQL version 4.1 was EOL on December 31, 2009 We should at least recommend modern versions of MySQL to users.
  clear cache on body close so that cache remains during rendering
  add a more restricted codepath for templates fixes #13390
  refactor generator tests to use block form of Tempfile
  Fix typo [ci skip]
  Move finish_template as the last public method in the generator
  Minor typos fix [ci skip]
  make `change_column_null` reversible. Closes #13576.
  create/drop test and development databases only if RAILS_ENV is nil
  Revert "Speedup String#to"
  typo fix in test name. [ci skip].
  `core_ext/string/access.rb` test what we are documenting.
  Fix typo in image_tag documentation
  ...

Conflicts:
	activerecord/lib/active_record/associations/join_dependency/join_association.rb
	activerecord/lib/active_record/relation/query_methods.rb

2 files changed, 31 insertions, 9 deletions

diff --git a/activerecord/test/cases/attribute_methods/read_test.rb b/activerecord/test/cases/attribute_methods/read_test.rb
index 8d8ff2f952..c0659fddef 100644
--- a/activerecord/test/cases/attribute_methods/read_test.rb
+++ b/activerecord/test/cases/attribute_methods/read_test.rb
@@ -15,13 +15,6 @@ module ActiveRecord
 
           include ActiveRecord::AttributeMethods
 
-          def self.define_attribute_methods
-            # Created in the inherited/included hook for "proper" ARs
-            @attribute_methods_mutex ||= Mutex.new
-
-            super
-          end
-
           def self.column_names
             %w{ one two three }
           end
@@ -56,9 +49,9 @@ module ActiveRecord
       end
 
       def test_attribute_methods_generated?
-        assert(!@klass.attribute_methods_generated?, 'attribute_methods_generated?')
+        assert_not @klass.method_defined?(:one)
         @klass.define_attribute_methods
-        assert(@klass.attribute_methods_generated?, 'attribute_methods_generated?')
+        assert @klass.method_defined?(:one)
       end
     end
   end
diff --git a/activerecord/test/cases/attribute_methods/serialization_test.rb b/activerecord/test/cases/attribute_methods/serialization_test.rb
new file mode 100644
index 0000000000..75de773961
--- /dev/null
+++ b/activerecord/test/cases/attribute_methods/serialization_test.rb
@@ -0,0 +1,29 @@
+require "cases/helper"
+
+module ActiveRecord
+  module AttributeMethods
+    class SerializationTest < ActiveSupport::TestCase
+      class FakeColumn < Struct.new(:name)
+        def type; :integer; end
+        def type_cast(s); "#{s}!"; end
+      end
+
+      class NullCoder
+        def load(v); v; end
+      end
+
+      def test_type_cast_serialized_value
+        value = Serialization::Attribute.new(NullCoder.new, "Hello world", :serialized)
+        type = Serialization::Type.new(FakeColumn.new)
+        assert_equal "Hello world!", type.type_cast(value)
+      end
+
+      def test_type_cast_unserialized_value
+        value = Serialization::Attribute.new(nil, "Hello world", :unserialized)
+        type = Serialization::Type.new(FakeColumn.new)
+        type.type_cast(value)
+        assert_equal "Hello world", type.type_cast(value)
+      end
+    end
+  end
+end