Revert change #31489.

That change was adding a hook to cope with the case when one was
undef'ining *ISA globs, in order to clean up correctly. However, this
broke the case where one was assiging an array ref to @ISA, which
is likely to be more common.
Conclusion: don't undef *ISA. (or more generally don't undef globs
that contain magical variables)
p4raw-link: @31489 on //depot/perl: 5be5c7a687aa37f2ea9dec7988eb57cad1f1ec24

p4raw-id: //depot/perl@31502

1 files changed, 3 insertions, 25 deletions

diff --git a/hv.c b/hv.c
index adbfbdf0e0..cf0f3f4524 100644
--- a/hv.c
+++ b/hv.c
@@ -1518,19 +1518,12 @@ Perl_hv_free_ent(pTHX_ HV *hv, register HE *entry)
 {
     dVAR;
     SV *val;
-    I32 isa_changing = 0;
 
     if (!entry)
 	return;
     val = HeVAL(entry);
-
-    if(HvNAME_get(hv) && val && isGV(val)) {
-        if(GvCVu((GV*)val))
-            mro_method_changed_in(hv);	/* deletion of method from stash */
-        else if(GvAV((GV*)val) && strEQ(GvNAME((GV*)val), "ISA"))
-            isa_changing = 1;
-    }
-
+    if (val && isGV(val) && GvCVu(val) && HvNAME_get(hv))
+        mro_method_changed_in(hv);	/* deletion of method from stash */
     SvREFCNT_dec(val);
     if (HeKLEN(entry) == HEf_SVKEY) {
 	SvREFCNT_dec(HeKEY_sv(entry));
@@ -1541,8 +1534,6 @@ Perl_hv_free_ent(pTHX_ HV *hv, register HE *entry)
     else
 	Safefree(HeKEY_hek(entry));
     del_HE(entry);
-
-    if(isa_changing) mro_isa_changed_in(hv);	/* deletion of @ISA from stash */
 }
 
 void
@@ -1853,21 +1844,8 @@ Perl_hv_undef(pTHX_ HV *hv)
     DEBUG_A(Perl_hv_assert(aTHX_ hv));
     xhv = (XPVHV*)SvANY(hv);
 
-    /* If it's a stash, undef the @ISA and call
-       mro_isa_changed_in before proceeding with
-       the rest of the destruction */
-    if ((name = HvNAME_get(hv)) && !PL_dirty) {
-        GV** gvp;
-        GV* gv;
-        AV* isa;
-
-        gvp = (GV**)hv_fetchs(hv, "ISA", FALSE);
-        gv = gvp ? *gvp : NULL;
-        isa = (gv && isGV_with_GP(gv)) ? GvAV(gv) : NULL;
-    
-        if(isa) av_undef(isa);
+    if ((name = HvNAME_get(hv)) && !PL_dirty)
         mro_isa_changed_in(hv);
-    }
 
     hfreeentries(hv);
     if (name) {