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Re: SV_CHECK_THINKFIRST() needs to be rethought and further COWwoes....

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From:
Dave Mitchell
Date:
March 25, 2013 12:13
Subject:
Re: SV_CHECK_THINKFIRST() needs to be rethought and further COWwoes....
Message ID:
20130325121330.GN2413@iabyn.com
On Mon, Mar 25, 2013 at 10:14:18AM +0100, demerphq wrote:
> To make things worse btw, IMO we have a real issue with COW, in that
> a) COW strings no longer have the READONLY flag set, code that wants
> to do an inplace modification based on this flag not being set will
> silently start modifying COW strings.
> 
> Lastly, I thought COW was disabled, but I see lots of code related to
> it. Devel::Peek still reports keys() as being COW, etc.
> 
> I think we have a real mess on our hands here. I feel really pessimistic.

My (vague) understanding is that although general COW strings have been
disabled, the pre-existing  shared hash key mechanism is still there, but
rather than using the FAKE/READONLY flag combination, it uses the new IsCOW
flag to indicate the sharedness

-- 
Nothing ventured, nothing lost.

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