1 files changed, 43 insertions, 8 deletions

diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index 36834bbd36..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:
@@ -110,7 +110,7 @@ module ActiveModel
     #   person.errors.include?(:name) # => true
     #   person.errors.include?(:age)  # => false
     def include?(attribute)
-      messages[attribute].present?
+      messages.key?(attribute) && messages[attribute].present?
     end
     alias :has_key? :include?
     alias :key? :include?
@@ -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 # => {}
     #
@@ -346,7 +346,7 @@ module ActiveModel
     #   # => {:name=>["can't be empty"]}
     def add_on_empty(attributes, options = {})
       ActiveSupport::Deprecation.warn(<<-MESSAGE.squish)
-        ActiveModel::Errors#add_on_empty is deprecated and will be removed in Rails 5.1
+        ActiveModel::Errors#add_on_empty is deprecated and will be removed in Rails 5.1.
 
         To achieve the same use:
 
@@ -368,7 +368,7 @@ module ActiveModel
     #   # => {:name=>["can't be blank"]}
     def add_on_blank(attributes, options = {})
       ActiveSupport::Deprecation.warn(<<-MESSAGE.squish)
-        ActiveModel::Errors#add_on_blank is deprecated and will be removed in Rails 5.1
+        ActiveModel::Errors#add_on_blank is deprecated and will be removed in Rails 5.1.
 
         To achieve the same use:
 
@@ -486,12 +486,23 @@ module ActiveModel
         default: defaults,
         model: @base.model_name.human,
         attribute: @base.class.human_attribute_name(attribute),
-        value: value
+        value: value,
+        object: @base
       }.merge!(options)
 
       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
@@ -505,6 +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
@@ -525,7 +547,20 @@ module ActiveModel
   class StrictValidationFailed < StandardError
   end
 
+  # Raised when attribute values are out of range.
+  class RangeError < ::RangeError
+  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