Re: [perl #23207] persistant sideffect involving bitwise xor and substr

Message-ID: <20030803150005.GA1319@ratsnest.hole>

p4raw-id: //depot/perl@20462

diff --git a/pp.c b/pp.c
index 8a7632a..2958fba 100644 (file)
--- a/pp.c
+++ b/pp.c
@@ -3111,6 +3111,8 @@ PP(pp_substr)
                sv_upgrade(TARG, SVt_PVLV);
                sv_magic(TARG, Nullsv, PERL_MAGIC_substr, Nullch, 0);
            }
+           else
+               (void)SvOK_off(TARG);
 
            LvTYPE(TARG) = 'x';
            if (LvTARG(TARG) != sv) {

diff --git a/t/op/substr.t b/t/op/substr.t
index 17f86e3..533f1a5 100755 (executable)
--- a/t/op/substr.t
+++ b/t/op/substr.t
@@ -1,6 +1,6 @@
 #!./perl
 
-print "1..175\n";
+print "1..176\n";
 
 #P = start of string  Q = start of substr  R = end of substr  S = end of string
 
@@ -592,3 +592,13 @@ ok 174, $x eq "\x{100}\x{200}\xFFb";
     $r[$_] = \ substr $s, $_, 1 for (0, 1);
     ok 175, join("", map { $$_ } @r) eq "ab";
 }
+
+# [perl #23207]
+{
+    sub ss {
+       substr($_[0],0,1) ^= substr($_[0],1,1) ^=
+       substr($_[0],0,1) ^= substr($_[0],1,1);
+    }
+    my $x = my $y = 'AB'; ss $x; ss $y;
+    ok 176, $x eq $y;
+}