concat interacts badly with magic

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

p4raw-id: //depot/perl@26185

diff --git a/pp_hot.c b/pp_hot.c
index 813b606..8502c1c 100644 (file)
--- 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);

diff --git a/t/op/tie.t b/t/op/tie.t
index 1fe37e1..8cb4539 100755 (executable)
--- a/t/op/tie.t
+++ b/t/op/tie.t
@@ -578,3 +578,10 @@ tie $h, "main";
 print $h,"\n";
 EXPECT
 3.3
+########
+sub TIESCALAR { bless {} }
+sub FETCH { shift()->{i} ++ }
+tie $h, "main";
+print $h.$h;
+EXPECT
+01