From c045b931b2afb3b2af6641a9943f65f295ee7da1 Mon Sep 17 00:00:00 2001
From: Eric Brine <ikegami@adaelis.com>
Date: Fri, 23 Oct 2009 19:05:40 -0400
Subject: [PATCH] Avoid adding magic with rvalue $#a

---
 pp.c |   17 ++++++++++++-----
 1 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/pp.c b/pp.c
index 6f56368..b9b8ba6 100644
--- a/pp.c
+++ b/pp.c
@@ -321,12 +321,19 @@ PP(pp_av2arylen)
 {
     dVAR; dSP;
     AV * const av = MUTABLE_AV(TOPs);
-    SV ** const sv = Perl_av_arylen_p(aTHX_ MUTABLE_AV(av));
-    if (!*sv) {
-       *sv = newSV_type(SVt_PVMG);
-       sv_magic(*sv, MUTABLE_SV(av), PERL_MAGIC_arylen, NULL, 0);
+    const I32 lvalue = PL_op->op_flags & OPf_MOD || LVRET;
+    if (lvalue) {
+       SV ** const sv = Perl_av_arylen_p(aTHX_ MUTABLE_AV(av));
+       if (!*sv) {
+           *sv = newSV_type(SVt_PVMG);
+           sv_magic(*sv, MUTABLE_SV(av), PERL_MAGIC_arylen, NULL, 0);
+       }
+       SETs(*sv);
+    } else {
+       SETs(sv_2mortal(newSViv(
+           AvFILL(MUTABLE_AV(av)) + CopARYBASE_get(PL_curcop)
+       )));
     }
-    SETs(*sv);
     RETURN;
 }

--
1.6.5