Only use the `_before_type_cast` in the form when from user input

While we don't want to change the form input when validations fail,
blindly using `_before_type_cast` will cause the input to display the
wrong data for any type which does additional work on database values.

3 files changed, 21 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/attribute.rb b/activerecord/lib/active_record/attribute.rb
index 88536eaac0..51e4fae62e 100644
--- a/activerecord/lib/active_record/attribute.rb
+++ b/activerecord/lib/active_record/attribute.rb
@@ -74,6 +74,10 @@ module ActiveRecord
       true
     end
 
+    def came_from_user?
+      false
+    end
+
     def ==(other)
       self.class == other.class &&
         name == other.name &&
@@ -99,6 +103,10 @@ module ActiveRecord
       def type_cast(value)
         type.type_cast_from_user(value)
       end
+
+      def came_from_user?
+        true
+      end
     end
 
     class WithCastValue < Attribute # :nodoc:
diff --git a/activerecord/lib/active_record/attribute_methods/before_type_cast.rb b/activerecord/lib/active_record/attribute_methods/before_type_cast.rb
index fd61febd57..56c1898551 100644
--- a/activerecord/lib/active_record/attribute_methods/before_type_cast.rb
+++ b/activerecord/lib/active_record/attribute_methods/before_type_cast.rb
@@ -28,6 +28,7 @@ module ActiveRecord
 
       included do
         attribute_method_suffix "_before_type_cast"
+        attribute_method_suffix "_came_from_user?"
       end
 
       # Returns the value of the attribute identified by +attr_name+ before
@@ -66,6 +67,10 @@ module ActiveRecord
       def attribute_before_type_cast(attribute_name)
         read_attribute_before_type_cast(attribute_name)
       end
+
+      def attribute_came_from_user?(attribute_name)
+        @attributes[attribute_name].came_from_user?
+      end
     end
   end
 end
diff --git a/activerecord/test/cases/attribute_methods_test.rb b/activerecord/test/cases/attribute_methods_test.rb
index 01ee1234a2..359503db98 100644
--- a/activerecord/test/cases/attribute_methods_test.rb
+++ b/activerecord/test/cases/attribute_methods_test.rb
@@ -888,6 +888,14 @@ class AttributeMethodsTest < ActiveRecord::TestCase
     assert_not_equal ['id'], @target.column_names
   end
 
+  def test_came_from_user
+    model = @target.first
+
+    assert_not model.id_came_from_user?
+    model.id = "omg"
+    assert model.id_came_from_user?
+  end
+
   private
 
   def new_topic_like_ar_class(&block)