PerlIO::get_layers: Treat numbers as strings

PerlIO::get_layers should not be ignoring an argument like 12, but
treating "12" (the string) as a filehandle, as those are both the
same value.

It’s an instance of the string/num bug, which is a bit like the
Unicode Bug.

This commit takes the conservative approach of expanding it to flat
scalars in general, but not references (in case we decide to do
something interesting later on, even though I think that would be a
bad idea).

diff --git a/t/io/layers.t b/t/io/layers.t
index 45afd7b..86d171c 100644 (file)
--- a/t/io/layers.t
+++ b/t/io/layers.t
@@ -35,7 +35,7 @@ if (${^UNICODE} & 1) {
 } else {
     $UTF8_STDIN = 0;
 }
-my $NTEST = 59 - (($DOSISH || !$FASTSTDIO) ? 7 : 0) - ($DOSISH ? 7 : 0)
+my $NTEST = 60 - (($DOSISH || !$FASTSTDIO) ? 7 : 0) - ($DOSISH ? 7 : 0)
     + $UTF8_STDIN;
 
 sub PerlIO::F_UTF8 () { 0x00008000 } # from perliol.h
@@ -246,4 +246,8 @@ EOT
     $t = '';
     $f = 0; PerlIO::get_layers $t;
     is $f, 1, '1 fetch on tied string';
+
+    # No distinction between nums and strings
+    open "12", "<:crlf", "test.pl" or die "$0 cannot open test.pl: $!";
+    ok PerlIO::get_layers(12), 'str/num arguments are treated identically';
 }

diff --git a/universal.c b/universal.c
index 36800b8..9d743ab 100644 (file)
--- a/universal.c
+++ b/universal.c
@@ -1006,7 +1006,7 @@ XS(XS_PerlIO_get_layers)
        sv = POPs;
        gv = MAYBE_DEREF_GV(sv);
 
-       if (!gv && SvPOKp(sv))
+       if (!gv && !SvROK(sv))
            gv = gv_fetchsv_nomg(sv, 0, SVt_PVIO);
 
        if (gv && (io = GvIO(gv))) {