concat interacts badly with magic

Message-ID: <20051121170339.GA8214@rpc142.cs.man.ac.uk>

p4raw-id: //depot/perl@26185

1 files changed, 10 insertions, 2 deletions

diff --git a/pp_hot.c b/pp_hot.c
index 813b606b0b..8502c1c9a1 100644
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -148,11 +148,14 @@ PP(pp_concat)
     dPOPTOPssrl;
     bool lbyte;
     STRLEN rlen;
-    const char *rpv = SvPV_const(right, rlen);	/* mg_get(right) happens here */
-    const bool rbyte = !DO_UTF8(right);
+    const char *rpv;
+    bool rbyte;
     bool rcopied = FALSE;
 
     if (TARG == right && right != left) {
+	/* mg_get(right) may happen here ... */
+	rpv = SvPV_const(right, rlen);
+	rbyte = !DO_UTF8(right);
 	right = sv_2mortal(newSVpvn(rpv, rlen));
 	rpv = SvPV_const(right, rlen);	/* no point setting UTF-8 here */
 	rcopied = TRUE;
@@ -179,6 +182,11 @@ PP(pp_concat)
 	    SvUTF8_off(TARG);
     }
 
+    /* or mg_get(right) may happen here */
+    if (!rcopied) {
+	rpv = SvPV_const(right, rlen);
+	rbyte = !DO_UTF8(right);
+    }
     if (lbyte != rbyte) {
 	if (lbyte)
 	    sv_utf8_upgrade_nomg(TARG);