Fix [perl #35929] : PerlIO::scalar didn't understand $/ = ""

because PerlIOScalar_unread was broken.
Bump version number of PerlIO::scalar to 0.04.

p4raw-id: //depot/perl@24543

3 files changed, 17 insertions, 4 deletions

diff --git a/ext/PerlIO/scalar/scalar.pm b/ext/PerlIO/scalar/scalar.pm
index 7eb936eacb..43685bf31d 100644
--- a/ext/PerlIO/scalar/scalar.pm
+++ b/ext/PerlIO/scalar/scalar.pm
@@ -1,5 +1,5 @@
 package PerlIO::scalar;
-our $VERSION = '0.03';
+our $VERSION = '0.04';
 use XSLoader ();
 XSLoader::load 'PerlIO::scalar';
 1;
diff --git a/ext/PerlIO/scalar/scalar.xs b/ext/PerlIO/scalar/scalar.xs
index 55a5fd8057..160deb2191 100644
--- a/ext/PerlIO/scalar/scalar.xs
+++ b/ext/PerlIO/scalar/scalar.xs
@@ -106,9 +106,8 @@ PerlIOScalar_unread(pTHX_ PerlIO * f, const void *vbuf, Size_t count)
 {
     PerlIOScalar *s = PerlIOSelf(f, PerlIOScalar);
     char *dst = SvGROW(s->var, (STRLEN)s->posn + count);
+    s->posn -= count;
     Move(vbuf, dst + s->posn, count, char);
-    s->posn += count;
-    SvCUR_set(s->var, (STRLEN)s->posn);
     SvPOK_on(s->var);
     return count;
 }
diff --git a/ext/PerlIO/t/scalar.t b/ext/PerlIO/t/scalar.t
index 818aab575f..8b43acb17a 100644
--- a/ext/PerlIO/t/scalar.t
+++ b/ext/PerlIO/t/scalar.t
@@ -15,7 +15,7 @@ BEGIN {
 }
 
 $| = 1;
-print "1..26\n";
+print "1..27\n";
 
 my $fh;
 my $var = "ok 2\n";
@@ -149,3 +149,17 @@ $data = undef;
 open(MEM, '<', \$data) or die "Fail: $!\n";
 my $x = join '', <MEM>;
 print $x eq '' ? "ok 26\n" : "not ok 26\n";
+
+{
+    # [perl #35929] verify that works with $/ (i.e. test PerlIOScalar_unread)
+    my $s = <<'EOF';
+line A
+line B
+a third line
+EOF
+    open(F, '<', \$s) or die "Could not open string as a file";
+    local $/ = "";
+    my $ln = <F>;
+    close F;
+    print $ln eq $s ? "ok 27\n" : "not ok 27\n";
+}