9 files changed, 47 insertions, 17 deletions
diff --git a/activemodel/Rakefile b/activemodel/Rakefile
index 9982d49bcb..036815a987 100644
--- a/activemodel/Rakefile
+++ b/activemodel/Rakefile
@@ -5,7 +5,6 @@ dir = File.dirname(__FILE__)
 task :default => :test
 
 task :package
-task "package:clean"
 
 Rake::TestTask.new do |t|
   t.libs << "test"
diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index 685e235730..6f2c8c1c53 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -71,8 +71,8 @@ module ActiveModel
     #   end
     def initialize(base)
       @base     = base
-      @messages = Hash.new { |messages, attribute| messages[attribute] = [] }
-      @details  = Hash.new { |details, attribute| details[attribute] = [] }
+      @messages = apply_default_array({})
+      @details = apply_default_array({})
     end
 
     def initialize_dup(other) # :nodoc:
@@ -310,9 +310,9 @@ module ActiveModel
     # <tt>:strict</tt> option can also be set to any other exception.
     #
     #   person.errors.add(:name, :invalid, strict: true)
-    #   # => ActiveModel::StrictValidationFailed: name is invalid
+    #   # => ActiveModel::StrictValidationFailed: Name is invalid
     #   person.errors.add(:name, :invalid, strict: NameIsInvalid)
-    #   # => NameIsInvalid: name is invalid
+    #   # => NameIsInvalid: Name is invalid
     #
     #   person.errors.messages # => {}
     #
@@ -493,6 +493,16 @@ module ActiveModel
       I18n.translate(key, options)
     end
 
+    def marshal_dump
+      [@base, without_default_proc(@messages), without_default_proc(@details)]
+    end
+
+    def marshal_load(array)
+      @base, @messages, @details = array
+      apply_default_array(@messages)
+      apply_default_array(@details)
+    end
+
   private
     def normalize_message(attribute, message, options)
       case message
@@ -506,6 +516,17 @@ module ActiveModel
     def normalize_detail(message, options)
       { error: message }.merge(options.except(*CALLBACKS_OPTIONS + MESSAGE_OPTIONS))
     end
+
+    def without_default_proc(hash)
+      hash.dup.tap do |new_h|
+        new_h.default_proc = nil
+      end
+    end
+
+    def apply_default_array(hash)
+      hash.default_proc = proc { |h, key| h[key] = [] }
+      hash
+    end
   end
 
   # Raised when a validation cannot be corrected by end users and are considered
@@ -531,6 +552,15 @@ module ActiveModel
   end
 
   # Raised when unknown attributes are supplied via mass assignment.
+  #
+  #   class Person
+  #     include ActiveModel::AttributeAssignment
+  #     include ActiveModel::Validations
+  #   end
+  #
+  #   person = Person.new
+  #   person.assign_attributes(name: 'Gorby')
+  #   # => ActiveModel::UnknownAttributeError: unknown attribute 'name' for Person.
   class UnknownAttributeError < NoMethodError
     attr_reader :record, :attribute
 
diff --git a/activemodel/lib/active_model/validations.rb b/activemodel/lib/active_model/validations.rb
index 8159b9b1d3..a10d2285a2 100644
--- a/activemodel/lib/active_model/validations.rb
+++ b/activemodel/lib/active_model/validations.rb
@@ -304,8 +304,6 @@ module ActiveModel
     # Runs all the specified validations and returns +true+ if no errors were
     # added otherwise +false+.
     #
-    # Aliased as validate.
-    #
     #   class Person
     #     include ActiveModel::Validations
     #
diff --git a/activemodel/lib/active_model/validations/callbacks.rb b/activemodel/lib/active_model/validations/callbacks.rb
index 52111e5442..a201f72ed0 100644
--- a/activemodel/lib/active_model/validations/callbacks.rb
+++ b/activemodel/lib/active_model/validations/callbacks.rb
@@ -29,8 +29,7 @@ module ActiveModel
       end
 
       module ClassMethods
-        # Defines a callback that will get called right before validation
-        # happens.
+        # Defines a callback that will get called right before validation.
         #
         #   class Person
         #     include ActiveModel::Validations
@@ -65,8 +64,7 @@ module ActiveModel
           set_callback(:validation, :before, *args, &block)
         end
 
-        # Defines a callback that will get called right after validation
-        # happens.
+        # Defines a callback that will get called right after validation.
         #
         #   class Person
         #     include ActiveModel::Validations
diff --git a/activemodel/lib/active_model/validations/numericality.rb b/activemodel/lib/active_model/validations/numericality.rb
index ad7012df48..9a0a0655de 100644
--- a/activemodel/lib/active_model/validations/numericality.rb
+++ b/activemodel/lib/active_model/validations/numericality.rb
@@ -120,7 +120,7 @@ module ActiveModel
       # * <tt>:only_integer</tt> - Specifies whether the value has to be an
       #   integer, e.g. an integral value (default is +false+).
       # * <tt>:allow_nil</tt> - Skip validation if attribute is +nil+ (default is
-      #   +false+). Notice that for fixnum and float columns empty strings are
+      #   +false+). Notice that for Integer and Float columns empty strings are
       #   converted to +nil+.
       # * <tt>:greater_than</tt> - Specifies the value must be greater than the
       #   supplied value.
diff --git a/activemodel/test/cases/errors_test.rb b/activemodel/test/cases/errors_test.rb
index fbf208836f..c90ee7021c 100644
--- a/activemodel/test/cases/errors_test.rb
+++ b/activemodel/test/cases/errors_test.rb
@@ -427,4 +427,13 @@ class ErrorsTest < ActiveModel::TestCase
     assert_equal [:name], person.errors.messages.keys
     assert_equal [:name], person.errors.details.keys
   end
+
+  test "errors are marshalable" do
+    errors = ActiveModel::Errors.new(Person.new)
+    errors.add(:name, :invalid)
+    serialized = Marshal.load(Marshal.dump(errors))
+
+    assert_equal errors.messages, serialized.messages
+    assert_equal errors.details, serialized.details
+  end
 end
diff --git a/activemodel/test/cases/helper.rb b/activemodel/test/cases/helper.rb
index 44c26e4f10..c589fd2c33 100644
--- a/activemodel/test/cases/helper.rb
+++ b/activemodel/test/cases/helper.rb
@@ -1,5 +1,4 @@
 require 'active_model'
-require 'active_support/core_ext/string/access'
 
 # Show backtraces for deprecated behavior for quicker cleanup.
 ActiveSupport::Deprecation.debug = true
diff --git a/activemodel/test/cases/validations/length_validation_test.rb b/activemodel/test/cases/validations/length_validation_test.rb
index ee901b75fb..11dce1df20 100644
--- a/activemodel/test/cases/validations/length_validation_test.rb
+++ b/activemodel/test/cases/validations/length_validation_test.rb
@@ -355,7 +355,7 @@ class LengthValidationTest < ActiveModel::TestCase
     assert_equal ["Your essay must be at least 5 words."], t.errors[:content]
   end
 
-  def test_validates_length_of_for_fixnum
+  def test_validates_length_of_for_integer
     Topic.validates_length_of(:approved, is: 4)
 
     t = Topic.new("title" => "uhohuhoh", "content" => "whatever", approved: 1)
diff --git a/activemodel/test/models/project.rb b/activemodel/test/models/project.rb
deleted file mode 100644
index 581b6dc0b3..0000000000
--- a/activemodel/test/models/project.rb
+++ /dev/null
@@ -1,3 +0,0 @@
-class Project
-  include ActiveModel::DeprecatedMassAssignmentSecurity
-end