Patch for ruby_1_8_7 singleton.rb

gistfile1.diff

Index: lib/singleton.rb
===================================================================
--- lib/singleton.rb	(revision 32126)
+++ lib/singleton.rb	(working copy)
@@ -94,9 +94,12 @@
         @__instance__ = new
       ensure
         if @__instance__
-          class <<self
-            remove_method :instance
-            def instance; @__instance__ end
+          # Check method existence to reduce redefinition warning.
+          unless self.respond_to?(:instance)
+            # It's doing test-then-set without a lock so there's a race to
+            # override existing method that causes the redefinition warning.
+            # We allow it since method redefinition is thread-safe for calling.
+            def self.instance; @__instance__ end
           end
         else
           @__instance__ = nil #  failed instance creation
@@ -111,9 +114,9 @@
         @__instance__ = new
       ensure
         if @__instance__
-          class <<self
-            remove_method :instance
-            def instance; @__instance__ end
+          # See the comment for self.instance above.
+          unless self.respond_to?(:instance)
+            def self.instance; @__instance__ end
           end
         else
           @__instance__ = nil