Precomputing the hash value for a string representable in bytes, but passed in

in UTF-8, would result in storing the wrong hash value in the hash, and hence
failing lookups. I guess not that much XS code precomputes hash values.

1 files changed, 5 insertions, 0 deletions

diff --git a/hv.c b/hv.c
index 78a1097250..b764c5593e 100644
--- a/hv.c
+++ b/hv.c
@@ -606,6 +606,11 @@ Perl_hv_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen,
 	    if (flags & HVhek_FREEKEY)
 		Safefree(keysave);
             flags |= HVhek_WASUTF8 | HVhek_FREEKEY;
+	    /* If the caller calculated a hash, it was on the sequence of
+	       octets that are the UTF-8 form. We've now changed the sequence
+	       of octets stored to that of the equivalent byte representation,
+	       so the hash we need is different.  */
+	    hash = 0;
 	}
     }