Fix regression in Numericality validator where extra decimal places on

a user input for a decimal column were ignored by numerically validations

activemodel/CHANGELOG.md

+*   Fix regression in numericality validator when comparing Decimal and Float input 
+    values with more scale than the schema.
+
+    *Bradley Priest*
+
 *   Fix methods `#keys`, `#values` in `ActiveModel::Errors`.
 
     Change `#keys` to only return the keys that don't have empty messages.

activemodel/lib/active_model/validations/numericality.rb

@@ -36,7 +36,9 @@ def validate_each(record, attr_name, value)
           return
         end
 
-        unless raw_value.is_a?(Numeric)
+        if raw_value.is_a?(Numeric)
+          value = raw_value
+        else
           value = parse_raw_value_as_a_number(raw_value)
         end
 

activerecord/test/cases/validations_test.rb

@@ -167,6 +167,20 @@ def test_numericality_validation_with_mutation
     assert topic.valid?
   end
 
+  def test_numericality_validation_checks_against_raw_value
+    klass = Class.new(Topic) do
+      def self.model_name
+        ActiveModel::Name.new(self, nil, "Topic")
+      end
+      attribute :wibble, :decimal, scale: 2, precision: 9
+      validates_numericality_of :wibble, greater_than_or_equal_to: BigDecimal.new("97.18")
+    end
+
+    assert_not klass.new(wibble: "97.179").valid?
+    assert_not klass.new(wibble: 97.179).valid?
+    assert_not klass.new(wibble: BigDecimal.new("97.179")).valid?
+  end
+
   def test_acceptance_validator_doesnt_require_db_connection
     klass = Class.new(ActiveRecord::Base) do
       self.table_name = "posts"