marshal.rb

# The minimal reproduction case

    require 'active_support/all'
    Time.zone = "UTC"
    Marshal.load(Marshal.dump(Time.zone.now))

# Dumping in 2.1, 2.0, and RBX-2.0.0

    r2.1.0dev :001 > require 'active_support/all'
     => true
    2.1.0dev :002 > Time.zone = "UTC"
     => "UTC"

    2.1.0dev :003 > Marshal.dump(Time.zone.now)
     => "\x04\bU: ActiveSupport::TimeWithZone[\bIu:\tTime\r\xF6d\x1C\xC0\x9F(\xE3\xD0\t:\rnano_numi\x02\xC1\x02:\rnano_deni\x06:\rsubmicro\"\apP:\tzoneI\"\bUTC\x06:\x06ETI\"\bUTC\x06;\vT@\t"

    2.0.0p247 :001 >  require 'active_support/all'
     => true
    2.0.0p247 :002 > Time.zone = "UTC"
     => "UTC"
    2.0.0p247 :003 > Marshal.dump(Time.zone.now)
     => "\x04\bU: ActiveSupport::TimeWithZone[\bIu:\tTime\r\xF6d\x1C\xC0\xD8\xB4\x81\xD6\t:\rnano_numi\x02`\x02:\rnano_deni\x06:\rsubmicro\"\a`\x80:\tzoneI\"\bUTC\x06:\x06ETI\"\bUTC\x06;\vT@\t"

    rubinius-2.0.0n280 :001 > require 'active_support/all'
     => true
    rubinius-2.0.0n280 :002 > Time.zone = "UTC"
     => "UTC"
    rubinius-2.0.0n280 :003 > Marshal.dump(Time.zone.now)
     => "\x04\bU: ActiveSupport::TimeWithZone[\bIu:\tTime\r\xF6d\x1C\xC0Z\x87\xAE\xD8\x06:\tzoneI\"\bUTC\x06:\x06ETI\"\bUTC\x06;\bT@\a"

# Loading

# In RBX, loading the string from Ruby 2.1 works:

    rubinius-2.0.0n280 :004 > Marshal.load("\x04\bU: ActiveSupport::TimeWithZone[\bIu:\tTime\r\xF6d\x1C\xC0\x9F(\xE3\xD0\t:\rnano_numi\x02\xC1\x02:\rnano_deni\x06:\rsubmicro\"\apP:\tzoneI\"\bUTC\x06:\x06ETI\"\bUTC\x06;\vTt")
    [2013-10-07 22:52:14 UTC, "UTC", 2013-10-07 22:52:14 UTC]
     => Mon, 07 Oct 2013 22:52:14 UTC +00:00

# The 2.0 string works

    rubinius-2.0.0n280 :005 > Marshal.load("\x04\bU: ActiveSupport::TimeWithZone[\bIu:\tTime\r\xF6d\x1C\xC0\xD8\xB4\x81\xD6\t:\rnano_numi\x02`\x02:\rnano_deni\x06:\rsubmicro\"\a`\x80:\tzoneI\"\bUTC\x06:\x06ETI\"\bUTC\x06;T@\t")
    [2013-10-07 22:53:40 UTC, "UTC", 2013-10-07 22:53:40 UTC]
     => Mon, 07 Oct 2013 22:53:40 UTC +00:00

# The RBX string blows up

    rubinius-2.0.0n280 :006 > Marshal.load("\x04\bU: ActiveSupport::TimeWithZone[\bIu:\tTime\r\xF6d\x1C\xC0Z\x87\xAE\xD8\x06:\tzoneI\"\bUTC\x06:\x06ETI\"\bUTC\x06;\bT@\a")
    [2013-10-07 22:54:10 UTC, "UTC", "UTC"]
    NoMethodError: undefined method `utc' on an instance of String.
            from kernel/delta/kernel.rb:78:in `utc (method_missing)'
            from /usr/local/rvm/gems/rbx-head/gems/activesupport-3.2.15.rc1/lib/active_support/time_with_zone.rb:321:in `marshal_load'
            from kernel/common/marshal.rb:830:in `construct_user_marshal'
            from kernel/common/marshal.rb:500:in `construct'
            from kernel/common/marshal.rb:1176:in `load'
            from (irb):6
            from kernel/common/block_environment.rb:53:in `call_on_instance'
            from kernel/common/eval.rb:176:in `eval'
            from kernel/common/kernel.rb:440:in `loop'
            from kernel/bootstrap/proc.rb:20:in `call'
            from kernel/common/throw_catch.rb:30:in `catch'
            from kernel/common/throw_catch.rb:8:in `register'
            from kernel/common/throw_catch.rb:29:in `catch'
            from kernel/bootstrap/proc.rb:20:in `call'
            from kernel/common/throw_catch.rb:30:in `catch'
            from kernel/common/throw_catch.rb:8:in `register'
            from kernel/common/throw_catch.rb:29:in `catch'
            from /usr/local/rvm/gems/rbx-head@global/gems/rubysl-irb-2.0.3/bin/irb:12:in `__script__'
            from kernel/common/kernel.rb:427:in `load'
            from /usr/local/rvm/gems/rbx-head@global/bin/irb:19:in `__script__'
            from kernel/delta/code_loader.rb:66:in `load_script'
            from kernel/delta/code_loader.rb:182:in `load_script'
            from kernel/loader.rb:648:in `script'
            from kernel/loader.rb:830:in `main'rubinius-2.0.0n280 :007 >