Perl_newHVhv() did not correctly copy hashes with non-shared keys

It created a hash built with non-shared keys, but left the "shared keys"
flag set on the hash.

This hasn't been spotted in 20 years, which shows just how much we use
hashes with unshared keys.

1 files changed, 8 insertions, 0 deletions

diff --git a/hv.c b/hv.c
index c821f78054..06fe493f3f 100644
--- a/hv.c
+++ b/hv.c
@@ -1593,6 +1593,14 @@ Perl_newHVhv(pTHX_ HV *ohv)
         Newx(a, PERL_HV_ARRAY_ALLOC_BYTES(hv_max+1), char);
         ents = (HE**)a;
 
+        if (shared) {
+            /* Shared is the default - it should have been set by newHV(). */
+            assert(HvSHAREKEYS(hv));
+        }
+        else {
+            HvSHAREKEYS_off(hv);
+        }
+
         /* In each bucket... */
         for (i = 0; i <= hv_max; i++) {
             HE *prev = NULL;