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[PATCH] Re: [perl #19135] string eval turns off readonlyness on lexicals

Father Chrysostomos
September 19, 2010 12:09
[PATCH] Re: [perl #19135] string eval turns off readonlyness on lexicals
Message ID:
The readonliness is turned off explicitly in pad_free under ithreads. See also bug #19022, which resulted from the same change. There is some discussion there, too, but nobody seemed to know exactly why the readonliness needed to be turned off.

Change 4761/2aa1bed, from January of 2000, added that SvREADONLY_off. It is supposed to make sure that pad entries that were constants will not be constants the next time they are used.

My question is: When the addresses of those scalars are reused, won’t the scalars be wiped clean? (In case it’s not obvious, I have very little idea how pads actually work.)

I tried simply deleting that SvREADONLY_off, and all tests pass (see the first attached patch).

Then I thought that maybe I should check that the SV is freed, and only then do SvREADONLY_off, to preserve the original intent of change 4761/2aa1bed. That worked too.

So, here are two patches. Take your pick. Perl Programming lists via nntp and http.
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