Merge pull request rails#41877 from Shopify/simplify-constantize

Directly delegate `constantize` to `Object.const_get`

Author: fxn

activesupport/lib/active_support/inflector/methods.rb

@@ -277,38 +277,7 @@ def foreign_key(class_name, separate_class_name_and_id_with_underscore = true)
     # NameError is raised when the name is not in CamelCase or the constant is
     # unknown.
     def constantize(camel_cased_word)
-      if camel_cased_word.blank? || !camel_cased_word.include?("::")
-        Object.const_get(camel_cased_word)
-      else
-        names = camel_cased_word.split("::")
-
-        # Trigger a built-in NameError exception including the ill-formed constant in the message.
-        Object.const_get(camel_cased_word) if names.empty?
-
-        # Remove the first blank element in case of '::ClassName' notation.
-        names.shift if names.size > 1 && names.first.empty?
-
-        names.inject(Object) do |constant, name|
-          if constant == Object
-            constant.const_get(name)
-          else
-            candidate = constant.const_get(name)
-            next candidate if constant.const_defined?(name, false)
-            next candidate unless Object.const_defined?(name)
-
-            # Go down the ancestors to check if it is owned directly. The check
-            # stops when we reach Object or the end of ancestors tree.
-            constant = constant.ancestors.inject(constant) do |const, ancestor|
-              break const    if ancestor == Object
-              break ancestor if ancestor.const_defined?(name, false)
-              const
-            end
-
-            # owner is in Object, so raise
-            constant.const_get(name, false)
-          end
-        end
-      end
+      Object.const_get(camel_cased_word)
     end
 
     # Tries to find a constant with the name specified in the argument string.