1 files changed, 16 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/core_ext/date/behavior.rb b/activesupport/lib/active_support/core_ext/date/behavior.rb
index 011cc17cbf..6f8f7c6a82 100644
--- a/activesupport/lib/active_support/core_ext/date/behavior.rb
+++ b/activesupport/lib/active_support/core_ext/date/behavior.rb
@@ -7,6 +7,22 @@ module ActiveSupport #:nodoc:
         def acts_like_date?
           true
         end
+
+        # Date memoizes some instance methods using metaprogramming to wrap
+        # the methods with one that caches the result in an instance variable.
+        # If a Date is frozen but the memoized method hasn't been called, the
+        # first call will result in a frozen object error since the memo
+        # instance variable is uninitialized. Work around by eagerly memoizing
+        # before freezing.
+        def freeze #:nodoc:
+          self.class.private_instance_methods(false).each do |m|
+            if m.to_s =~ /\A__\d+__\Z/
+              instance_variable_set(:"@#{m}", [send(m)])
+            end
+          end
+
+          super
+        end
       end
     end
   end