From 204263bc1eb63f1dfd6180c05dca8cec2c319504 Mon Sep 17 00:00:00 2001
From: Father Chrysostomos <sprout@cpan.org>
Date: Sat, 24 Dec 2011 23:27:30 -0800
Subject: [PATCH] select() sometimes returns invalid string

The return value from select() is sometimes a string, and sometimes a
globref.  It was originally always a string, but typeglobs not to be
found under their names in their stashes started being returned as
references in 5.002 beta 1 (4633a7c4b).  The logic is a little faulty,
though, as sometimes the name that is returned cannot be used to find
the glob:

$ perl -le '
    open "foo::bar", ">/dev/ttys009";
    select foo::bar;
    my $handle = \*foo::bar;
    my $stash = \%foo::bar;
    *foo:: = *bar::;
    print "hello";
    select select;
    print "hello" or warn $!
'
Bad file descriptor at -e line 9.

In this example, /dev/ttys009 is another terminal window.  "hello"
only appears once, not twice.
---
 pp_sys.c      |  5 ++++-
 t/op/select.t | 10 +++++++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/pp_sys.c b/pp_sys.c
index 78a51ae..661e0fc 100644
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -1231,7 +1231,10 @@ PP(pp_select)
     if (! hv)
 	XPUSHs(&PL_sv_undef);
     else {
-	GV * const * const gvp = (GV**)hv_fetch(hv, GvNAME(egv), HEK_UTF8(GvNAME_HEK(egv)) ? -GvNAMELEN(egv) : GvNAMELEN(egv), FALSE);
+	GV * const * const gvp =
+	    HvENAME(hv)
+		? (GV**)hv_fetch(hv, GvNAME(egv), HEK_UTF8(GvNAME_HEK(egv)) ? -GvNAMELEN(egv) : GvNAMELEN(egv), FALSE)
+		: NULL;
 	if (gvp && *gvp == egv) {
 	    gv_efullname4(TARG, PL_defoutgv, NULL, TRUE);
 	    XPUSHTARG;
diff --git a/t/op/select.t b/t/op/select.t
index 7c27f6f..06caf1d 100644
--- a/t/op/select.t
+++ b/t/op/select.t
@@ -5,7 +5,7 @@ BEGIN {
     require './test.pl';
 }
 
-plan reverse 7;
+plan reverse 8;
 
 
 open my $fh, "test.pl" or die "$0 unfortunately cannot open test.pl: $!";
@@ -17,3 +17,11 @@ is select, $fh, 'the ref returned references the right referent';
 is select(STDOUT), $fh, 'select previous ref when setting to bareword';
 is select, 'main::STDOUT', 'switching back to STDOUT';
 is ref\select, 'SCALAR', 'and STDOUT is a plain string';
+
+open foo::bar, "test.pl" or die "$0 sadly cannot open test.pl: $!";
+select foo::bar;
+$handle = \*foo::bar;
+$stash = \%foo::;
+*foo:: = *bar::;
+is select, $handle,
+    'select returns ref for glob whose stash has been detached';
-- 
2.7.4