Merge pull request rails#48106 from Shopify/deep-dup-modules

`Object#deep_dup` no longer duplicate named classes and modules.

Author: byroot

activerecord/test/cases/serialized_attribute_test.rb

@@ -9,6 +9,12 @@
 class SerializedAttributeTest < ActiveRecord::TestCase
   def setup
     ActiveRecord.use_yaml_unsafe_load = true
+    @yaml_column_permitted_classes_default = ActiveRecord.yaml_column_permitted_classes
+  end
+
+  def teardown
+    Topic.serialize("content")
+    ActiveRecord.yaml_column_permitted_classes = @yaml_column_permitted_classes_default
   end
 
   fixtures :topics, :posts
@@ -23,8 +29,8 @@ class ImportantTopic < Topic
     serialize :important, type: Hash
   end
 
-  teardown do
-    Topic.serialize("content")
+  class ClassifiedTopic < Topic
+    serialize :important, type: Class
   end
 
   def test_serialize_does_not_eagerly_load_columns
@@ -166,6 +172,14 @@ def test_serialized_string_attribute
     assert_equal(myobj, topic.content)
   end
 
+  def test_serialized_class_attribute
+    ActiveRecord.yaml_column_permitted_classes += [Class]
+
+    topic = ClassifiedTopic.create(important: Symbol).reload
+    assert_equal(Symbol, topic.important)
+    assert_not_empty ClassifiedTopic.where(important: Symbol)
+  end
+
   def test_nil_serialized_attribute_without_class_constraint
     topic = Topic.new
     assert_nil topic.content
@@ -551,9 +565,17 @@ def test_serialized_attribute_works_under_concurrent_initial_access
 
 class SerializedAttributeTestWithYamlSafeLoad < SerializedAttributeTest
   def setup
+    @use_yaml_unsafe_load = ActiveRecord.use_yaml_unsafe_load
+    @yaml_column_permitted_classes_default = ActiveRecord.yaml_column_permitted_classes
     ActiveRecord.use_yaml_unsafe_load = false
   end
 
+  def teardown
+    Topic.serialize("content")
+    ActiveRecord.yaml_column_permitted_classes = @yaml_column_permitted_classes_default
+    ActiveRecord.use_yaml_unsafe_load = @use_yaml_unsafe_load
+  end
+
   def test_serialized_attribute
     Topic.serialize("content", type: String)
 

activesupport/CHANGELOG.md

@@ -1,3 +1,21 @@
+*   `Object#deep_dup` no longer duplicate named classes and modules.
+
+    Before:
+
+    ```ruby
+    hash = { class: Object, module: Kernel }
+    hash.deep_dup # => {:class=>#<Class:0x00000001063ffc80>, :module=>#<Module:0x00000001063ffa00>}
+    ```
+
+    After:
+
+    ```ruby
+    hash = { class: Object, module: Kernel }
+    hash.deep_dup # => {:class=>Object, :module=>Kernel}
+    ```
+
+    *Jean Boussier*
+
 *   Consistently raise an `ArgumentError` if the `ActiveSupport::Cache` key is blank.
 
     *Joshua Young*

activesupport/lib/active_support/core_ext/object/deep_dup.rb

@@ -53,3 +53,19 @@ def deep_dup
     hash
   end
 end
+
+class Module
+  # Returns a copy of module or class if it's anonymous. If it's
+  # named, returns +self+.
+  #
+  #   Object.deep_dup == Object # => true
+  #   klass = Class.new
+  #   klass.deep_dup == klass # => false
+  def deep_dup
+    if name.nil?
+      super
+    else
+      self
+    end
+  end
+end

activesupport/test/core_ext/object/deep_dup_test.rb

@@ -66,4 +66,16 @@ def test_deep_dup_with_mutable_frozen_key
 
     assert_not_equal hash.keys, dup.keys
   end
+
+  def test_named_modules_arent_duped
+    hash = { class: Object, module: Kernel }
+    assert_equal hash, hash.deep_dup
+  end
+
+  def test_anonymous_modules_are_duped
+    hash = { class: Class.new, module: Module.new }
+    duped_hash = hash.deep_dup
+    assert_not_equal hash[:class], duped_hash[:class]
+    assert_not_equal hash[:module], duped_hash[:module]
+  end
 end