Fix Ruby's Time marshaling bug in pre-1.9 versions of Ruby: utc instances are now correctly unmarshaled with a utc zone instead of the system local zone [#900 state:resolved]

1 files changed, 22 insertions, 1 deletions

diff --git a/activesupport/lib/active_support/core_ext/time.rb b/activesupport/lib/active_support/core_ext/time.rb
index ea50511a96..2006cf4946 100644
--- a/activesupport/lib/active_support/core_ext/time.rb
+++ b/activesupport/lib/active_support/core_ext/time.rb
@@ -1,11 +1,32 @@
 require 'date'
 require 'time'
 
-# Ruby 1.8-cvs and 1.9 define private Time#to_date
 class Time
+  # Ruby 1.8-cvs and 1.9 define private Time#to_date
   %w(to_date to_datetime).each do |method|
     public method if private_instance_methods.include?(method)
   end
+
+  # Pre-1.9 versions of Ruby have a bug with marshaling Time instances, where utc instances are
+  # unmarshaled in the local zone, instead of utc. We're layering behavior on the _dump and _load
+  # methods so that utc instances can be flagged on dump, and coerced back to utc on load.
+  if RUBY_VERSION < '1.9'
+    class << self
+      alias_method :_original_load, :_load
+      def _load(marshaled_time)
+        time = _original_load(marshaled_time)
+        utc = time.send(:remove_instance_variable, '@marshal_with_utc_coercion')
+        utc ? time.utc : time
+      end
+    end
+    
+    alias_method :_original_dump, :_dump
+    def _dump(*args)
+      obj = self.frozen? ? self.dup : self
+      obj.instance_variable_set('@marshal_with_utc_coercion', utc?)
+      obj._original_dump(*args)
+    end
+  end
 end
 
 require 'active_support/core_ext/time/behavior'