[ruby-core:24574] Re: [Bug #1711] Marshal Failing to Round-Trip Certain Recurisve Data Structures

Hi,

In message "Re: [ruby-core:24105] [Bug #1711] Marshal Failing to Round-Trip Certain Recurisve Data Structures"
    on Thu, 2 Jul 2009 02:30:15 +0900, Run Paint Run Run <[e-mail]> writes:

|I have attached a script that fails to round-trip a recursive data structure on 1.9, but succeeds on 1.8. IOW, it prints true on 1.8; false on 1.9. I haven't been able to reduce it further because I'm unfamiliar with Marshal.

1.9 Marshal.load with proc is incompatible with 1.8, as following:

  * 1.8 load ignores the value returned from proc, whereas 1.9 load
    replaces the object by the value from proc.

  * 1.9 load calls proc for recursively visited data.  1.8 dump only
    calls proc once.

That is to allow rebuilding loading data using proc.  For
the example in [ruby-core:24361], replacing 

 myproc = Proc.new { |o| arr << o }

by

 myproc = Proc.new { |o| arr << o; o }

should work as expected.  The future action would be either:

 (a) the new 1.9 behavior has meaning.  since virtually no one uses
     Marshal.load with proc, it's OK to change it for a good reason.

 (b) incompatibility is bad.  should be reverted to the original 1.8
     behavior.

 (c) or probably add another optional (or keyword) argument to enable
     the new behavior, keeping the old behavior by default.

Any opinion?

							matz.