From: Andrew Mitchell <amitchell@...>
Date: 2008-05-23T17:33:28+09:00
Subject: Re: customized serialization unreliable????


>    def marshal_dump()
>       return [@version,@data]
>    end

If there are actually classes built on instance methods marshal_dump and 
marshal_load, then Marshal would be completely ignoring those methods. 
Assuming you meant "_dump" which is the instance method to overload for 
customized serialization, and either "self._load" or klassname._load 
which is the class method for the same, then this would be happening:

Array.to_s will be called in Marshal.dump because it expects a string.
For example, with the YYY class:
@version = 1
@data = ["e", "i"]
_dump returns [1, ["e", "i"]]
The Marshaling process will form "1ei"

Your Loading process with "1ei" will give
@version = 1
@data = "e" # instead of ["e", "i"]


If for whatever reason you are Marshaling the results of your 
marshal_dump methods -- Marshal.dump(my_yyy.marshal_dump) --, then you 
have neglected to properly handle object graph cycles, and shared 
references.

Further, from the ruby-doc Marshal class:
    "Some objects cannot be dumped: if the objects to be dumped include 
bindings, procedure or method objects, instances of class IO, or 
singleton objects, a TypeError will be raised."
-- 
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