Merge pull request rails#53347 from rails/revert-53337-opt-attr-dup

Revert "ActiveModel::Attribute: elide dup for immutable types"

Author: byroot

activemodel/lib/active_model/attribute.rb

@@ -96,14 +96,6 @@ def with_type(type)
       end
     end
 
-    def deep_dup # :nodoc:
-      if @type.mutable?
-        dup
-      else
-        self # If the underlying type is immutable we can get away with not duping
-      end
-    end
-
     def type_cast(*)
       raise NotImplementedError
     end

activemodel/lib/active_model/attribute/user_provided_default.rb

@@ -26,10 +26,6 @@ def with_type(type)
         self.class.new(name, user_provided_value, type, original_attribute)
       end
 
-      # Can't elide dup when a default is provided.
-      # See Attribute#deep_dup
-      alias_method :deep_dup, :dup
-
       def marshal_dump
         result = [
           name,

activemodel/lib/active_model/type/string.rb

@@ -29,10 +29,6 @@ def to_immutable_string
         )
       end
 
-      def mutable? # :nodoc:
-        true
-      end
-
       private
         def cast_value(value)
           case value

activerecord/test/cases/base_test.rb

@@ -1117,14 +1117,16 @@ def test_default_char_types
     end
 
     def test_default_in_local_time
-      with_timezone_config default: :local do
-        default = Default.new
+      with_env_tz do
+        with_timezone_config default: :local do
+          default = Default.new
 
-        assert_equal Date.new(2004, 1, 1), default.fixed_date
-        assert_equal Time.local(2004, 1, 1, 0, 0, 0, 0), default.fixed_time
+          assert_equal Date.new(2004, 1, 1), default.fixed_date
+          assert_equal Time.local(2004, 1, 1, 0, 0, 0, 0), default.fixed_time
 
-        if current_adapter?(:PostgreSQLAdapter)
-          assert_equal Time.utc(2004, 1, 1, 0, 0, 0, 0), default.fixed_time_with_time_zone
+          if current_adapter?(:PostgreSQLAdapter)
+            assert_equal Time.utc(2004, 1, 1, 0, 0, 0, 0), default.fixed_time_with_time_zone
+          end
         end
       end
     end
@@ -1157,6 +1159,29 @@ def test_default_in_utc_with_time_zone
       end
     end
 
+    def test_switching_default_time_zone
+      with_env_tz do
+        2.times do
+          with_timezone_config default: :local do
+            assert_equal Time.local(2004, 1, 1, 0, 0, 0, 0), Default.new.fixed_time
+          end
+          with_timezone_config default: :utc do
+            assert_equal Time.utc(2004, 1, 1, 0, 0, 0, 0), Default.new.fixed_time
+          end
+        end
+      end
+    end
+
+    def test_mutating_time_objects
+      with_env_tz do
+        with_timezone_config default: :local do
+          assert_equal Time.local(2004, 1, 1, 0, 0, 0, 0), Default.new.fixed_time
+          assert_equal Time.utc(2004, 1, 1, 5, 0, 0, 0), Default.new.fixed_time.utc
+          assert_equal Time.local(2004, 1, 1, 0, 0, 0, 0), Default.new.fixed_time
+        end
+      end
+    end
+
     unless in_memory_db?
       def test_connection_in_local_time
         with_timezone_config default: :utc do