[perl #101486] Make PL_curstash refcounted

This stops PL_curstash from pointing to a freed-and-reused scalar in
cases like ‘package Foo; BEGIN {*Foo:: = *Bar::}’.

In such cases, another BEGIN block, or any subroutine definition,
would cause a crash.  Now it just happily proceeds.  newATTRSUB and
newXS have been modified not to call mro_method_changed_in in such
cases, as it doesn’t make sense.

1 files changed, 1 insertions, 1 deletions

diff --git a/sv.c b/sv.c
index 3efbc39ea7..2e0553ac73 100644
--- a/sv.c
+++ b/sv.c
@@ -13212,7 +13212,7 @@ perl_clone_using(PerlInterpreter *proto_perl, UV flags,
 
     /* symbol tables */
     PL_defstash		= hv_dup_inc(proto_perl->Idefstash, param);
-    PL_curstash		= hv_dup(proto_perl->Icurstash, param);
+    PL_curstash		= hv_dup_inc(proto_perl->Icurstash, param);
     PL_debstash		= hv_dup(proto_perl->Idebstash, param);
     PL_globalstash	= hv_dup(proto_perl->Iglobalstash, param);
     PL_curstname	= sv_dup_inc(proto_perl->Icurstname, param);