update ActiveModel::Errors documentation and minor fixes [ci skip]

3 files changed, 103 insertions, 64 deletions

diff --git a/activemodel/lib/active_model/conversion.rb b/activemodel/lib/active_model/conversion.rb
index 43d248e5cb..89d87a8b6f 100644
--- a/activemodel/lib/active_model/conversion.rb
+++ b/activemodel/lib/active_model/conversion.rb
@@ -27,7 +27,7 @@ module ActiveModel
 
     # If your object is already designed to implement all of the Active Model
     # you can use the default <tt>:to_model</tt> implementation, which simply
-    # returns self.
+    # returns +self+.
     #
     #   class Person
     #     include ActiveModel::Conversion
diff --git a/activemodel/lib/active_model/dirty.rb b/activemodel/lib/active_model/dirty.rb
index 7014d8114f..9bd5f903cd 100644
--- a/activemodel/lib/active_model/dirty.rb
+++ b/activemodel/lib/active_model/dirty.rb
@@ -80,8 +80,8 @@ module ActiveModel
   #   person.changes        # => {"name" => ["Bill", "Bob"]}
   #
   # If an attribute is modified in-place then make use of <tt>[attribute_name]_will_change!</tt>
-  # to mark that the attribute is changing. Otherwise ActiveModel can't track changes to
-  # in-place attributes.
+  # to mark that the attribute is changing. Otherwise ActiveModel can't track
+  # changes to in-place attributes.
   #
   #   person.name_will_change!
   #   person.name_change    # => ["Bill", "Bill"]
@@ -115,7 +115,7 @@ module ActiveModel
     end
 
     # Returns a hash of changed attributes indicating their original
-    # and new values like <tt>attr => [original value, new value]</tt>. 
+    # and new values like <tt>attr => [original value, new value]</tt>.
     #
     #   person.changes # => {}
     #   person.name = 'bob'
diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index aba6618b56..e879e931d6 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -54,8 +54,8 @@ module ActiveModel
   # The above allows you to do:
   #
   #   p = Person.new
-  #   p.validate!             # => ["can not be nil"]
-  #   p.errors.full_messages  # => ["name can not be nil"]
+  #   person.validate!            # => ["can not be nil"]
+  #   person.errors.full_messages # => ["name can not be nil"]
   #   # etc..
   class Errors
     include Enumerable
@@ -81,28 +81,49 @@ module ActiveModel
       super
     end
 
-    # Clear the messages
+    # Clear the error messages.
+    #
+    #   person.errors.full_messages # => ["name can not be nil"]
+    #   person.errors.clear
+    #   person.errors.full_messages # => []
     def clear
       messages.clear
     end
 
-    # Do the error messages include an error with key +error+?
+    # Returns +true+ if the error messages include an error for the given key
+    # +error+, +false+ otherwise.
+    #
+    #   person.errors.messages        # => { :name => ["can not be nil"] }
+    #   person.errors.include?(:name) # => true
+    #   person.errors.include?(:age)  # => false
     def include?(error)
       (v = messages[error]) && v.any?
     end
     alias :has_key? :include?
 
-    # Get messages for +key+
+    # Get messages for +key+.
+    #
+    #   person.errors.messages   # => { :name => ["can not be nil"] }
+    #   person.errors.get(:name) # => ["can not be nil"]
+    #   person.errors.get(:age)  # => nil
     def get(key)
       messages[key]
     end
 
-    # Set messages for +key+ to +value+
+    # Set messages for +key+ to +value+.
+    #
+    #   person.errors.get(:name) # => ["can not be nil"]
+    #   person.errors.set(:name, ["can't be nil"])
+    #   person.errors.get(:name) # => ["can't be nil"]
     def set(key, value)
       messages[key] = value
     end
 
-    # Delete messages for +key+
+    # Delete messages for +key+. Returns the deleted messages.
+    #
+    #   person.errors.get(:name)    # => ["can not be nil"]
+    #   person.errors.delete(:name) # => ["can not be nil"]
+    #   person.errors.get(:name)    # => nil
     def delete(key)
       messages.delete(key)
     end
@@ -110,16 +131,16 @@ module ActiveModel
     # When passed a symbol or a name of a method, returns an array of errors
     # for the method.
     #
-    #   p.errors[:name]   # => ["can not be nil"]
-    #   p.errors['name']  # => ["can not be nil"]
+    #   person.errors[:name]  # => ["can not be nil"]
+    #   person.errors['name'] # => ["can not be nil"]
     def [](attribute)
       get(attribute.to_sym) || set(attribute.to_sym, [])
     end
 
     # Adds to the supplied attribute the supplied error message.
     #
-    #   p.errors[:name] = "must be set"
-    #   p.errors[:name] # => ['must be set']
+    #   person.errors[:name] = "must be set"
+    #   person.errors[:name] # => ['must be set']
     def []=(attribute, error)
       self[attribute] << error
     end
@@ -128,13 +149,13 @@ module ActiveModel
     # Yields the attribute and the error for that attribute. If the attribute
     # has more than one error message, yields once for each error message.
     #
-    #   p.errors.add(:name, "can't be blank")
-    #   p.errors.each do |attribute, error|
+    #   person.errors.add(:name, "can't be blank")
+    #   person.errors.each do |attribute, error|
     #     # Will yield :name and "can't be blank"
     #   end
     #
-    #   p.errors.add(:name, "must be specified")
-    #   p.errors.each do |attribute, error|
+    #   person.errors.add(:name, "must be specified")
+    #   person.errors.each do |attribute, error|
     #     # Will yield :name and "can't be blank"
     #     # then yield :name and "must be specified"
     #   end
@@ -146,44 +167,54 @@ module ActiveModel
 
     # Returns the number of error messages.
     #
-    #   p.errors.add(:name, "can't be blank")
-    #   p.errors.size # => 1
-    #   p.errors.add(:name, "must be specified")
-    #   p.errors.size # => 2
+    #   person.errors.add(:name, "can't be blank")
+    #   person.errors.size # => 1
+    #   person.errors.add(:name, "must be specified")
+    #   person.errors.size # => 2
     def size
       values.flatten.size
     end
 
-    # Returns all message values
+    # Returns all message values.
+    #
+    #   person.errors.messages # => { :name => ["can not be nil", "must be specified"] }
+    #   person.errors.values   # => [["can not be nil", "must be specified"]]
     def values
       messages.values
     end
 
-    # Returns all message keys
+    # Returns all message keys.
+    #
+    #   person.errors.messages # => { :name => ["can not be nil", "must be specified"] }
+    #   person.errors.keys     # => [:name]
     def keys
       messages.keys
     end
 
-    # Returns an array of error messages, with the attribute name included
+    # Returns an array of error messages, with the attribute name included.
     #
-    #   p.errors.add(:name, "can't be blank")
-    #   p.errors.add(:name, "must be specified")
-    #   p.errors.to_a # => ["name can't be blank", "name must be specified"]
+    #   person.errors.add(:name, "can't be blank")
+    #   person.errors.add(:name, "must be specified")
+    #   person.errors.to_a # => ["name can't be blank", "name must be specified"]
     def to_a
       full_messages
     end
 
     # Returns the number of error messages.
-    #   p.errors.add(:name, "can't be blank")
-    #   p.errors.count # => 1
-    #   p.errors.add(:name, "must be specified")
-    #   p.errors.count # => 2
+    #
+    #   person.errors.add(:name, "can't be blank")
+    #   person.errors.count # => 1
+    #   person.errors.add(:name, "must be specified")
+    #   person.errors.count # => 2
     def count
       to_a.size
     end
 
-    # Returns true if no errors are found, false otherwise.
+    # Returns +true+ if no errors are found, +false+ otherwise.
     # If the error message is a string it can be empty.
+    #
+    #   person.errors.full_messages # => ["name can not be nil"]
+    #   person.errors.empty?        # => false
     def empty?
       all? { |k, v| v && v.empty? && !v.is_a?(String) }
     end
@@ -191,9 +222,9 @@ module ActiveModel
 
     # Returns an xml formatted representation of the Errors hash.
     #
-    #   p.errors.add(:name, "can't be blank")
-    #   p.errors.add(:name, "must be specified")
-    #   p.errors.to_xml
+    #   person.errors.add(:name, "can't be blank")
+    #   person.errors.add(:name, "must be specified")
+    #   person.errors.to_xml
     #   # =>
     #   #  <?xml version=\"1.0\" encoding=\"UTF-8\"?>
     #   #  <errors>
@@ -204,10 +235,13 @@ module ActiveModel
       to_a.to_xml({ :root => "errors", :skip_types => true }.merge!(options))
     end
 
-    # Returns an Hash that can be used as the JSON representation for this object.
-    # Options:
-    # * <tt>:full_messages</tt> - determines if json object should contain
-    #   full messages or not. Default: <tt>false</tt>.
+    # Returns an Hash that can be used as the JSON representation for this
+    # object. Also, You can pass the <tt>:full_messages</tt> option. This
+    # determines if the json object should contain full messages or not (false
+    # by default).
+    #
+    #   person.as_json                      # => { :name => ["can not be nil"] }
+    #   person.as_json(full_messages: true) # => { :name => ["name can not be nil"] }
     def as_json(options=nil)
       to_hash(options && options[:full_messages])
     end
@@ -224,12 +258,15 @@ module ActiveModel
       end
     end
 
-    # Adds +message+ to the error messages on +attribute+. More than one error can be added to the same
-    # +attribute+.
-    # If no +message+ is supplied, <tt>:invalid</tt> is assumed.
+    # Adds +message+ to the error messages on +attribute+. More than one error
+    # can be added to the same +attribute+. If no +message+ is supplied,
+    # <tt>:invalid</tt> is assumed.
+    #
+    # If +message+ is a symbol, it will be translated using the appropriate
+    # scope (see +generate_message+).
     #
-    # If +message+ is a symbol, it will be translated using the appropriate scope (see +generate_message+).
-    # If +message+ is a proc, it will be called, allowing for things like <tt>Time.now</tt> to be used within an error.
+    # If +message+ is a proc, it will be called, allowing for things like
+    # <tt>Time.now</tt> to be used within an error.
     def add(attribute, message = nil, options = {})
       message = normalize_message(attribute, message, options)
       if options[:strict]
@@ -239,7 +276,8 @@ module ActiveModel
       self[attribute] << message
     end
 
-    # Will add an error message to each of the attributes in +attributes+ that is empty.
+    # Will add an error message to each of the attributes in +attributes+
+    # that is empty.
     def add_on_empty(attributes, options = {})
       [attributes].flatten.each do |attribute|
         value = @base.send(:read_attribute_for_validation, attribute)
@@ -248,7 +286,8 @@ module ActiveModel
       end
     end
 
-    # Will add an error message to each of the attributes in +attributes+ that is blank (using Object#blank?).
+    # Will add an error message to each of the attributes in +attributes+ that
+    # is blank (using Object#blank?).
     def add_on_blank(attributes, options = {})
       [attributes].flatten.each do |attribute|
         value = @base.send(:read_attribute_for_validation, attribute)
@@ -256,10 +295,11 @@ module ActiveModel
       end
     end
 
-    # Returns true if an error on the attribute with the given message is present, false otherwise.
-    # +message+ is treated the same as for +add+.
-    #   p.errors.add :name, :blank
-    #   p.errors.added? :name, :blank # => true
+    # Returns +true+ if an error on the attribute with the given message is
+    # present, +false+ otherwise. +message+ is treated the same as for +add+.
+    #
+    #   person.errors.add :name, :blank
+    #   person.errors.added? :name, :blank # => true
     def added?(attribute, message = nil, options = {})
       message = normalize_message(attribute, message, options)
       self[attribute].include? message
@@ -267,22 +307,21 @@ module ActiveModel
 
     # Returns all the full error messages in an array.
     #
-    #   class Company
+    #   class Person
     #     validates_presence_of :name, :address, :email
-    #     validates_length_of :name, :in => 5..30
+    #     validates_length_of :name, in: 5..30
     #   end
     #
-    #   company = Company.create(:address => '123 First St.')
-    #   company.errors.full_messages # =>
-    #     ["Name is too short (minimum is 5 characters)", "Name can't be blank", "Email can't be blank"]
+    #   person = Person.create(address: '123 First St.')
+    #   person.errors.full_messages
+    #   # => ["Name is too short (minimum is 5 characters)", "Name can't be blank", "Email can't be blank"]
     def full_messages
       map { |attribute, message| full_message(attribute, message) }
     end
 
     # Returns a full message for a given attribute.
     #
-    #   company.errors.full_message(:name, "is invalid")  # =>
-    #     "Name is invalid"
+    #   person.errors.full_message(:name, 'is invalid') # => "Name is invalid"
     def full_message(attribute, message)
       return message if attribute == :base
       attr_name = attribute.to_s.tr('.', '_').humanize
@@ -298,10 +337,11 @@ module ActiveModel
     # (<tt>activemodel.errors.messages</tt>).
     #
     # Error messages are first looked up in <tt>models.MODEL.attributes.ATTRIBUTE.MESSAGE</tt>,
-    # if it's not there, it's looked up in <tt>models.MODEL.MESSAGE</tt> and if that is not
-    # there also, it returns the translation of the default message
-    # (e.g. <tt>activemodel.errors.messages.MESSAGE</tt>). The translated model name,
-    # translated attribute name and the value are available for interpolation.
+    # if it's not there, it's looked up in <tt>models.MODEL.MESSAGE</tt> and if
+    # that is not there also, it returns the translation of the default message
+    # (e.g. <tt>activemodel.errors.messages.MESSAGE</tt>). The translated model
+    # name, translated attribute name and the value are available for
+    # interpolation.
     #
     # When using inheritance in your models, it will check all the inherited
     # models too, but only if the model itself hasn't been found. Say you have
@@ -317,7 +357,6 @@ module ActiveModel
     # * <tt>activemodel.errors.messages.blank</tt>
     # * <tt>errors.attributes.title.blank</tt>
     # * <tt>errors.messages.blank</tt>
-    #
     def generate_message(attribute, type = :invalid, options = {})
       type = options.delete(:message) if options[:message].is_a?(Symbol)