8 files changed, 31 insertions, 21 deletions
diff --git a/activemodel/lib/active_model.rb b/activemodel/lib/active_model.rb
index b95c174d6e..7de259a60d 100644
--- a/activemodel/lib/active_model.rb
+++ b/activemodel/lib/active_model.rb
@@ -49,6 +49,7 @@ module ActiveModel
 
   eager_autoload do
     autoload :Errors
+    autoload :RangeError, 'active_model/errors'
     autoload :StrictValidationFailed, 'active_model/errors'
     autoload :UnknownAttributeError, 'active_model/errors'
   end
diff --git a/activemodel/lib/active_model/conversion.rb b/activemodel/lib/active_model/conversion.rb
index 9de6ea65be..a932ada45c 100644
--- a/activemodel/lib/active_model/conversion.rb
+++ b/activemodel/lib/active_model/conversion.rb
@@ -40,8 +40,8 @@ module ActiveModel
       self
     end
 
-    # Returns an Array of all key attributes if any is set, regardless if
-    # the object is persisted or not. Returns +nil+ if there are no key attributes.
+    # Returns an Array of all key attributes if any of the attributes is set, whether or not
+    # the object is persisted. Returns +nil+ if there are no key attributes.
     #
     #   class Person
     #     include ActiveModel::Conversion
diff --git a/activemodel/lib/active_model/dirty.rb b/activemodel/lib/active_model/dirty.rb
index fad4de9df5..90047c3c12 100644
--- a/activemodel/lib/active_model/dirty.rb
+++ b/activemodel/lib/active_model/dirty.rb
@@ -119,6 +119,9 @@ module ActiveModel
     extend ActiveSupport::Concern
     include ActiveModel::AttributeMethods
 
+    OPTION_NOT_GIVEN = Object.new # :nodoc:
+    private_constant :OPTION_NOT_GIVEN
+
     included do
       attribute_method_suffix '_changed?', '_change', '_will_change!', '_was'
       attribute_method_suffix '_previously_changed?', '_previous_change'
@@ -174,13 +177,10 @@ module ActiveModel
     end
 
     # Handles <tt>*_changed?</tt> for +method_missing+.
-    def attribute_changed?(attr, options = nil) #:nodoc:
-      result = changes_include?(attr)
-      if options
-        result &&= options[:to] == __send__(attr) if options.key?(:to)
-        result &&= options[:from] == changed_attributes[attr] if options.key?(:from)
-      end
-      result
+    def attribute_changed?(attr, from: OPTION_NOT_GIVEN, to: OPTION_NOT_GIVEN) # :nodoc:
+      !!changes_include?(attr) &&
+        (to == OPTION_NOT_GIVEN || to == __send__(attr)) &&
+        (from == OPTION_NOT_GIVEN || from == changed_attributes[attr])
     end
 
     # Handles <tt>*_was</tt> for +method_missing+.
@@ -189,7 +189,7 @@ module ActiveModel
     end
 
     # Handles <tt>*_previously_changed?</tt> for +method_missing+.
-    def attribute_previously_changed?(attr, options = {}) #:nodoc:
+    def attribute_previously_changed?(attr) #:nodoc:
       previous_changes_include?(attr)
     end
 
diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index d106f65fa2..696e6d31da 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -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 # => {}
     #
@@ -526,7 +526,20 @@ 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
 
diff --git a/activemodel/lib/active_model/gem_version.rb b/activemodel/lib/active_model/gem_version.rb
index 62862aa4e9..4a8ee915cf 100644
--- a/activemodel/lib/active_model/gem_version.rb
+++ b/activemodel/lib/active_model/gem_version.rb
@@ -6,9 +6,9 @@ module ActiveModel
 
   module VERSION
     MAJOR = 5
-    MINOR = 0
+    MINOR = 1
     TINY  = 0
-    PRE   = "beta3"
+    PRE   = "alpha"
 
     STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
   end
diff --git a/activemodel/lib/active_model/type/integer.rb b/activemodel/lib/active_model/type/integer.rb
index 2f73ede009..eea2280b22 100644
--- a/activemodel/lib/active_model/type/integer.rb
+++ b/activemodel/lib/active_model/type/integer.rb
@@ -46,7 +46,7 @@ module ActiveModel
 
       def ensure_in_range(value)
         unless range.cover?(value)
-          raise RangeError, "#{value} is out of range for #{self.class} with limit #{_limit}"
+          raise ActiveModel::RangeError, "#{value} is out of range for #{self.class} with limit #{_limit}"
         end
       end
 
diff --git a/activemodel/lib/active_model/validations/acceptance.rb b/activemodel/lib/active_model/validations/acceptance.rb
index c5c0cd4636..a04e5f347e 100644
--- a/activemodel/lib/active_model/validations/acceptance.rb
+++ b/activemodel/lib/active_model/validations/acceptance.rb
@@ -64,11 +64,7 @@ module ActiveModel
         private
 
         def convert_to_reader_name(method_name)
-          attr_name = method_name.to_s
-          if attr_name.end_with?("=")
-            attr_name = attr_name[0..-2]
-          end
-          attr_name
+          method_name.to_s.chomp('=')
         end
       end
     end
diff --git a/activemodel/lib/active_model/validator.rb b/activemodel/lib/active_model/validator.rb
index 109bf038b0..699f74ed17 100644
--- a/activemodel/lib/active_model/validator.rb
+++ b/activemodel/lib/active_model/validator.rb
@@ -100,7 +100,7 @@ module ActiveModel
     #   PresenceValidator.kind   # => :presence
     #   UniquenessValidator.kind # => :uniqueness
     def self.kind
-      @kind ||= name.split('::').last.underscore.sub(/_validator$/, '').to_sym unless anonymous?
+      @kind ||= name.split('::').last.underscore.chomp('_validator').to_sym unless anonymous?
     end
 
     # Accepts options that will be made available through the +options+ reader.