lib/active_support/dependencies.rb in activesupport-3.0.1 vs lib/active_support/dependencies.rb in activesupport-3.0.2

@@ -509,11 +509,16 @@
         raise name_error
       end
     end
 
     # Remove the constants that have been autoloaded, and those that have been
-    # marked for unloading.
+    # marked for unloading. Before each constant is removed a callback is sent
+    # to its class/module if it implements +before_remove_const+.
+    #
+    # The callback implementation should be restricted to cleaning up caches, etc.
+    # as the enviroment will be in an inconsistent state, e.g. other constants
+    # may have already been unloaded and not accessible.
     def remove_unloadable_constants!
       autoloaded_constants.each { |const| remove_constant const }
       autoloaded_constants.clear
       Reference.clear!
       explicitly_unloadable_constants.each { |const| remove_constant const }
@@ -634,9 +639,10 @@
       names = const.to_s.sub(/^::(Object)?/, 'Object::').split("::")
       to_remove = names.pop
       parent = Inflector.constantize(names * '::')
 
       log "removing constant #{const}"
+      constantize(const).before_remove_const if constantize(const).respond_to?(:before_remove_const)
       parent.instance_eval { remove_const to_remove }
 
       return true
     end