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Re^4: ref to read-only alias ... why? (notabug)

by dk (Chaplain)
on Jan 06, 2012 at 17:46 UTC ( #946636=note: print w/ replies, xml ) Need Help??


in reply to Re^3: ref to read-only alias ... why? (not consistent)
in thread ref to read-only alias ... why?

Heh, it's a 8-year old (!!!!) bug: https://rt.perl.org/rt3/Public/Bug/Display.html?id=21979 . With resolution that it's indeed a bug ... well, that situation doesn't seem good to me, when noone wants to touch a bug in 8 years. I wonder why.


Comment on Re^4: ref to read-only alias ... why? (notabug)
Re^5: ref to read-only alias ... why? (notabug)
by LanX (Canon) on Jan 06, 2012 at 17:49 UTC
    Thats what I expected.

    > I wonder why.

    IMHO legacy code would break if you die here.

    But a warning would be great.

    Cheers Rolf

      I agree on a warning, it would be a practical thing, after all. And after that, a real fix with 'die' a couple versions later should help the legacy code.

      Well anyway, I found the code suggested by ikegami, so would you guys review the patch please?

      --- pp.c.0 2012-01-06 01:07:34.511988700 +0100 +++ pp.c 2012-01-06 19:04:06.311428300 +0100 @@ -515,9 +515,11 @@ SvTEMP_off(sv); SvREFCNT_inc_void_NN(sv); } - else if (SvPADTMP(sv) && !IS_PADGV(sv)) + else if (SvPADTMP(sv) && !IS_PADGV(sv)) { + Perl_ck_warner(aTHX_ packWARN(WARN_MISC), + "Implicit copy of a read-only scalar due to aliasing"); sv = newSVsv(sv); - else { + } else { SvTEMP_off(sv); SvREFCNT_inc_void_NN(sv); }

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