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Postings from January 2017
On 27 January 2017 at 19:04, Hugo van der Sanden via RT <perlbug-followup@perl.org> wrote: > On Fri, 27 Jan 2017 08:02:14 -0800, demerphq wrote: >> On 27 January 2017 at 16:15, Hugo van der Sanden wrote: >> > I'm not entirely sure that I have a use case, but what I had in mind >> > was to modify the fixup loop as in your "this GOSUB may have been >> > optimized away" change, but combine it with a regexec-time check & >> > panic should we see a GOSUB that hasn't had its target set (which >> > requires inventing a way to flag that). Failing that, we should at >> > least have an assert at the point of fixup, for a clea[nr]er failure >> > mode. >> >> If we do this in debug mode only then I see no harm. > > I had planned to make it a mandatory panic (not only under DEBUGGING), instead of the SEGV or worse you would otherwise get. > >> Can I leave that part to you? > > For now yes - I had already had a go at it (assuming I could set arg2=0 and test that for "not set") but got a bunch of test failures, which I haven't tried to dig into yet. If I can't use arg2, I might want to use flags - but as far as I can see we don't ever actually use those as flags, so some caution will be needed. Wait wait. Are we talking about the same thing? I thought you were talking about guarding the code that produced the SEGV with logic like i posted in my GOSUB patch which I did not apply. I think the bulk of that patch is fine to apply. I just don't see the need to do those check except under debugging as we no longer optimise away parens. And really, the core idea of optimising a capturing paren is broken in the face of recursion. You simply cannot do it. So basically we are talking about adding guard code for a problem that should never occur. IMO that means a DEBUGGING only feature. Maybe I should just post the patch I am thinking of then you can do whatever you like on top, and then we get out of the game of broken telephone. (Will that term ever be modernized I wonder?) :-) cheers, Yves -- perl -Mre=debug -e "/just|another|perl|hacker/"Thread Previous | Thread Next