Switch the core MRO code over to HvENAME

This has the side-effect of fixing these one-liners:

$ perl5.13.5 -le' my $glob = \*foo::ISA; delete $::{"foo::"}; *$glob = *a'
Bus error
$ perl5.13.5 -le' my $glob = \*foo::ISA; delete $::{"foo::"}; *$glob = []'
Bus error
$ perl5.13.6 -le'sub baz; my $glob = \*foo::bar; delete $::{"foo::"}; *$glob = *baz;'
Bus error
$ perl5.13.6 -le'sub foo::bar; my $glob = \*foo::bar; delete $::{"foo::"}; *$glob = *baz;'
Bus error

In the first two cases the crash was inadvertently fixed (isn’t it
nice when that happens?) in 5.13.6 (by 6f86b615fa7), but there was
still a fatal error:
Can't call mro_isa_changed_in() on anonymous symbol table at -e line 1.

Because sv_clear calls ->DESTROY, if an object’s stash has been
detached from the symbol table, mro_get_linear_isa can be called on a
hash with no HvENAME. So HvNAME is used as a fallback for those cases.

1 files changed, 1 insertions, 1 deletions

diff --git a/scope.c b/scope.c
index eb464f91da..4a1b39933c 100644
--- a/scope.c
+++ b/scope.c
@@ -859,7 +859,7 @@ Perl_leave_scope(pTHX_ I32 base)
 	    if (SSPOPINT)
 		SvFAKE_on(gv);
             /* putting a method back into circulation ("local")*/
-	    if (GvCVu(gv) && (hv=GvSTASH(gv)) && HvNAME_get(hv))
+	    if (GvCVu(gv) && (hv=GvSTASH(gv)) && HvENAME_get(hv))
                 mro_method_changed_in(hv);
 	    SvREFCNT_dec(gv);
 	    break;