1 files changed, 72 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/deprecation/proxy_wrappers.rb b/activesupport/lib/active_support/deprecation/proxy_wrappers.rb
new file mode 100644
index 0000000000..1c268d0d9c
--- /dev/null
+++ b/activesupport/lib/active_support/deprecation/proxy_wrappers.rb
@@ -0,0 +1,72 @@
+module ActiveSupport
+  module Deprecation
+    class DeprecationProxy #:nodoc:
+      instance_methods.each { |m| undef_method m unless m =~ /^__/ }
+
+      # Don't give a deprecation warning on inspect since test/unit and error
+      # logs rely on it for diagnostics.
+      def inspect
+        target.inspect
+      end
+
+      private
+        def method_missing(called, *args, &block)
+          warn caller, called, args
+          target.__send__(called, *args, &block)
+        end
+    end
+
+    class DeprecatedObjectProxy < DeprecationProxy #:nodoc:
+      def initialize(object, message)
+        @object = object
+        @message = message
+      end
+
+      private
+        def target
+          @object
+        end
+
+        def warn(callstack, called, args)
+          ActiveSupport::Deprecation.warn(@message, callstack)
+        end
+    end
+
+    # Stand-in for <tt>@request</tt>, <tt>@attributes</tt>, <tt>@params</tt>, etc.
+    # which emits deprecation warnings on any method call (except +inspect+).
+    class DeprecatedInstanceVariableProxy < DeprecationProxy #:nodoc:
+      def initialize(instance, method, var = "@#{method}")
+        @instance, @method, @var = instance, method, var
+      end
+
+      private
+        def target
+          @instance.__send__(@method)
+        end
+
+        def warn(callstack, called, args)
+          ActiveSupport::Deprecation.warn("#{@var} is deprecated! Call #{@method}.#{called} instead of #{@var}.#{called}. Args: #{args.inspect}", callstack)
+        end
+    end
+
+    class DeprecatedConstantProxy < DeprecationProxy #:nodoc:
+      def initialize(old_const, new_const)
+        @old_const = old_const
+        @new_const = new_const
+      end
+
+      def class
+        target.class
+      end
+
+      private
+        def target
+          @new_const.to_s.constantize
+        end
+
+        def warn(callstack, called, args)
+          ActiveSupport::Deprecation.warn("#{@old_const} is deprecated! Use #{@new_const} instead.", callstack)
+        end
+    end
+  end
+end