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Re: [perl #75176] Symbol::delete_package does not free certain memoryassociated with package::ISA

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From:
demerphq
Date:
August 29, 2010 15:26
Subject:
Re: [perl #75176] Symbol::delete_package does not free certain memoryassociated with package::ISA
Message ID:
AANLkTinHUs7sEHLr_-NFjg6L7PNnZcUzrK=X-z+iU5_T@mail.gmail.com
On 29 August 2010 23:09, Father Chrysostomos <sprout@cpan.org> wrote:
>
> On Aug 22, 2010, at 5:46 PM, Father Chrysostomos wrote:
>
> Initially I planned to fix the isarev leaks by making appropriate
> adjustments to it whenever an @ISA is modified or a stash is freed. But,
> since stashes can be detached from the main tree of stashes ($stash = delete
> $::{"it::"}), they need to know whether they are still attached, so detached
> stashes don’t muddle up isarev and delete entries that are still needed
> (which would be worse than leaking).
>
> In the process of experimenting with that, I found that such stash
> manipulations already fail to update isa caches, which, too, would cause my
> proposed isarev changes to introduce regressions. So that’s what this patch
> is for.
>
> Here is a patch that deals with a couple more ways of manipulating stashes.
> I plan to work on assignment to empty stash elements next (or any stash
> elements that are not globs). I can do this by using PVLVs. But there are
> two approaches:
> 1. Do it just for access from Perl by adding it to pp_helem.
> 2. Do it for XS access as well, by modifying hv_fetch_ent instead (or
> hv_common, or wherever the actual code is).
> Number 1 makes it too easy for XS code to make changes without triggering
> mro_package_moved. mro_package_moved will also have to be made public (and
> probably given a better name).
> Number 2 is probably more reliable. perl’s internals can pass a flag to
> avoid the PVLVs. XS code that assumes that stash elements are never magical
> will be broken (code that specifically calls the _nomg forms to avoid the
> magic checks). Most XS code will continue to work.
> So in both cases, XS code will have to be modified (if there is any that
> plays with stashes). But in case 2 only code that is currently potentially
> buggy will have to change.
> I prefer number 2.

+	if (stype == SVt_PVHV) {
+	    const char * const name = GvNAME((GV*)dstr);
+	    const STRLEN len = GvNAMELEN(dstr);
+	    if (len > 1 && name[len-2] == ':' && name[len-1] == ':')
+		if(HvNAME(dref)) mro_package_moved((HV *)dref);
+		if(HvNAME(sref)) mro_package_moved((HV *)sref);
+	}

Did you miss a { } there? From the indenting it looks like the if ()
applies to both of the following ifs, but it is an if (EXPR) STMT; not
an IF (EXPR) BLOCK

yves



-- 
perl -Mre=debug -e "/just|another|perl|hacker/"

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