A version of change #21073 that works.

p4raw-link: @21073 on //depot/perl: b5a808db3c007cbb4159178941346ac3c6f968a7

p4raw-id: //depot/perl@21106

diff --git a/ext/PerlIO/scalar/scalar.xs b/ext/PerlIO/scalar/scalar.xs
index 0d56ecc..193b99f 100644 (file)
--- a/ext/PerlIO/scalar/scalar.xs
+++ b/ext/PerlIO/scalar/scalar.xs
@@ -25,7 +25,7 @@ PerlIOScalar_pushed(pTHX_ PerlIO * f, const char *mode, SV * arg,
     if (arg) {
        if (SvROK(arg)) {
            s->var = SvREFCNT_inc(SvRV(arg));
-           if (!SvPOK(s->var))
+           if (!SvPOK(s->var) && SvTYPE(SvRV(arg)) > SVt_NULL)
                (void)SvPV_nolen(s->var);
        }
        else {

diff --git a/ext/PerlIO/t/scalar.t b/ext/PerlIO/t/scalar.t
index 58ef97f..01e12b0 100644 (file)
--- a/ext/PerlIO/t/scalar.t
+++ b/ext/PerlIO/t/scalar.t
@@ -10,7 +10,7 @@ BEGIN {
 }
 
 $| = 1;
-print "1..24\n";
+print "1..25\n";
 
 my $fh;
 my $var = "ok 2\n";
@@ -126,3 +126,15 @@ close $fh;
 { package P; sub TIESCALAR {bless{}} sub FETCH {"ok 24\n"} }
 tie $p, P; open $fh, '<', \$p;
 print <$fh>;
+
+# don't warn when writing to an undefined scalar
+
+{
+    use warnings;
+    my $ok = 1;
+    local $SIG{__WARN__} = sub { $ok = 0; };
+    open my $fh, '>', \my $scalar;
+    print $fh "foo";
+    close $fh;
+    print $ok ? "ok 25\n" : "not ok 25\n";
+}