Make the second argument to `attribute` optional

While working on updating Paper Trail for 5.1 compatibility, I noticed
that I was required to pass a second argument to `attribute`. I didn't
intend for this to be the case, as `attribute :foo` is totally
reasonable shorthand for "I want `attr_accessor :foo`, but also have it
work with things like `.attributes` and `ActiveRecord::Dirty`"

3 files changed, 15 insertions, 1 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 08dd40080f..357e4c3016 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,9 @@
+*   Change the type argument of `ActiveRecord::Base#attribute` to be optional.
+    The default is now `ActiveRecord::Type::Value.new`, which provides no type
+    casting behavior.
+
+    *Sean Griffin*
+
 *   Fix that unsigned with zerofill is treated as signed.
 
     Fixes #27125.
diff --git a/activerecord/lib/active_record/attributes.rb b/activerecord/lib/active_record/attributes.rb
index dcbfca1c04..75f5ba3a96 100644
--- a/activerecord/lib/active_record/attributes.rb
+++ b/activerecord/lib/active_record/attributes.rb
@@ -191,7 +191,7 @@ module ActiveRecord
       # tracking is performed. The methods +changed?+ and +changed_in_place?+
       # will be called from ActiveModel::Dirty. See the documentation for those
       # methods in ActiveModel::Type::Value for more details.
-      def attribute(name, cast_type, **options)
+      def attribute(name, cast_type = Type::Value.new, **options)
         name = name.to_s
         reload_schema_from_cache
 
diff --git a/activerecord/test/cases/attributes_test.rb b/activerecord/test/cases/attributes_test.rb
index f4620ae2da..3705a6be89 100644
--- a/activerecord/test/cases/attributes_test.rb
+++ b/activerecord/test/cases/attributes_test.rb
@@ -255,5 +255,13 @@ module ActiveRecord
 
       assert_includes inspection, "non_existent_decimal"
     end
+
+    test "attributes do not require a type" do
+      klass = Class.new(OverloadedType) do
+        attribute :no_type
+      end
+      assert_equal 1, klass.new(no_type: 1).no_type
+      assert_equal "foo", klass.new(no_type: "foo").no_type
+    end
   end
 end