Fix memory leaks in mro_package_moved

This commit adds a new HV_FETCH_EMPTY_HE flag for hv_common. It is to
be used in conjunction with HV_FETCH_LVALUE. It just stops the newly-
created HE from having a new undef scalar assigned to it.

This allows code to call hv_common just once instead of an hv_exists/
hv_store pair.

It was such a double hv_common call that I was trying to avoid with
HV_FETCH_LVALUE, without realising that it was leaking.

1 files changed, 1 insertions, 1 deletions

diff --git a/hv.c b/hv.c
index da8d76421d..bc1d4f9eba 100644
--- a/hv.c
+++ b/hv.c
@@ -735,7 +735,7 @@ Perl_hv_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
 	return NULL;
     }
     if (action & HV_FETCH_LVALUE) {
-	val = newSV(0);
+	val = action & HV_FETCH_EMPTY_HE ? NULL : newSV(0);
 	if (SvMAGICAL(hv)) {
 	    /* At this point the old hv_fetch code would call to hv_store,
 	       which in turn might do some tied magic. So we need to make that