Fixes bug #15273, the return of the object caused

the stash of the object to be cloned, cloning the entire syntax
tree and all lexicals in there creating danglning copies to the
object. (Pararell but unlinked STASH tree).
This adds a new flag, when set it will use STASHES from the
thread we are joining into avoiding the problem.

p4raw-id: //depot/perl@18419

1 files changed, 12 insertions, 0 deletions

diff --git a/sv.c b/sv.c
index e522a47e38..08eac582e8 100644
--- a/sv.c
+++ b/sv.c
@@ -9346,6 +9346,18 @@ Perl_sv_dup(pTHX_ SV *sstr, CLONE_PARAMS* param)
     if (dstr)
 	return dstr;
 
+    if(param->flags & CLONEf_JOIN_IN) {
+        /** We are joining here so we don't want do clone
+	    something that is bad **/
+
+        if(SvTYPE(sstr) == SVt_PVHV &&
+	   HvNAME(sstr)) {
+	    /** don't clone stashes if they already exist **/
+	    HV* old_stash = gv_stashpv(HvNAME(sstr),0);
+	    return (SV*) old_stash;
+        }
+    }
+
     /* create anew and remember what it is */
     new_SV(dstr);
     ptr_table_store(PL_ptr_table, sstr, dstr);