Fix `read_attribute_before_type_cast` to consider attribute aliases

Numericality validations for aliased attributes are not able
to get the value of the attribute before type cast because
activerecord was trying to get the value of the attribute based
on attribute alias name and not the original attribute name.

Example of validation which would pass even if a invalid value
would be provided

    class MyModel < ActiveRecord::Base
      validates :aliased_balance, numericality: { greater_than_or_equal_to: 0 }
    end

If we instantiate MyModel like bellow it will be valid because
when numericality validation runs it will not be able to get the
value before type cast, so it uses the type casted value
which will be `0.0` and the validation will match.

    subject = MyModel.new(aliased_balance: "abcd")
    subject.valid?

But if we declare MyModel like this

    class MyModel < ActiveRecord::Base
      validates :balance, numericality: { greater_than_or_equal_to: 0 }
    end

and assign "abcd" value to `balance` when the validations
run the model will be invalid because activerecord will be able
to get the value before type cast.

With this change `read_attribute_before_type_cast` will be able to
get the value before type cast even when the attr_name is an
attribute_alias.

activerecord/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Fix `read_attribute_before_type_cast` to consider attribute aliases.
+
+    *Marcelo Lauxen*
+
 *   Support passing record to uniqueness validator `:conditions` callable:
 
     ```ruby

activerecord/lib/active_record/attribute_methods/before_type_cast.rb

@@ -46,7 +46,10 @@ module ActiveRecord
       #   task.read_attribute_before_type_cast('completed_on') # => "2012-10-21"
       #   task.read_attribute_before_type_cast(:completed_on)  # => "2012-10-21"
       def read_attribute_before_type_cast(attr_name)
-        attribute_before_type_cast(attr_name.to_s)
+        name = attr_name.to_s
+        name = self.class.attribute_aliases[name] || name
+
+        attribute_before_type_cast(name)
       end
 
       # Returns a hash of attributes before typecasting and deserialization.

activerecord/test/cases/attribute_methods_test.rb

@@ -12,6 +12,7 @@ require "models/category"
 require "models/reply"
 require "models/contact"
 require "models/keyboard"
+require "models/numeric_data"
 
 class AttributeMethodsTest < ActiveRecord::TestCase
   include InTimeZone
@@ -1087,6 +1088,11 @@ class AttributeMethodsTest < ActiveRecord::TestCase
     assert_equal "Topic::GeneratedAttributeMethods", mod.inspect
   end
 
+  test "read_attribute_before_type_cast with aliased attribute" do
+    model = NumericData.new(new_bank_balance: "abcd")
+    assert_equal "abcd", model.read_attribute_before_type_cast("new_bank_balance")
+  end
+
   private
     def new_topic_like_ar_class(&block)
       klass = Class.new(ActiveRecord::Base) do

activerecord/test/cases/validations/numericality_validation_test.rb

@@ -102,4 +102,12 @@ class NumericalityValidationTest < ActiveRecord::TestCase
 
     assert_not_predicate subject, :valid?
   end
+
+  def test_aliased_attribute
+    model_class.validates_numericality_of(:new_bank_balance, greater_or_equal_than: 0)
+
+    subject = model_class.new(new_bank_balance: "abcd")
+
+    assert_not_predicate subject, :valid?
+  end
 end

activerecord/test/models/numeric_data.rb

@@ -7,4 +7,6 @@ class NumericData < ActiveRecord::Base
   attribute :world_population, :big_integer
   attribute :my_house_population, :big_integer
   attribute :atoms_in_universe, :big_integer
+
+  alias_attribute :new_bank_balance, :bank_balance
 end