From 898f154f4805605718761c2b4165e13ada07ac80 Mon Sep 17 00:00:00 2001
From: Yasutaka ATARASHI <yakex@cpan.org>
Date: Tue, 13 Nov 2012 23:56:36 +0900
Subject: [PATCH] Add guard for the case Filter::tee is not available.

---
 lib/filtered.pm | 24 ++++++++++++++----------
 t/debug.pl      |  4 ++++
 2 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/lib/filtered.pm b/lib/filtered.pm
index e40a142..2189acb 100644
--- a/lib/filtered.pm
+++ b/lib/filtered.pm
@@ -121,17 +121,21 @@ sub filtered::hook::INC
 				$_ .= ' '.$self->{_WITH};
 			}
 			if(exists $ENV{FILTERED_ROOT}) {
-				my $asfile;
-				if(defined($self->{_AS})) {
-					$asfile = $self->{_AS};
-					$asfile =~ s@::@/@g;
-					$asfile .= '.pm';
+				if(eval { require Filter::tee; }) {
+					my $asfile;
+					if(defined($self->{_AS})) {
+						$asfile = $self->{_AS};
+						$asfile =~ s@::@/@g;
+						$asfile .= '.pm';
+					} else {
+						$asfile = $filename;
+					}
+					my $dir = dirname($ENV{FILTERED_ROOT}.'/'.$asfile);
+					File::Path::make_path($dir) if ! -d $dir;
+					$_ .= "; use Filter::tee '".$ENV{FILTERED_ROOT}.'/'.$asfile."'";
 				} else {
-					$asfile = $filename;
+					warn 'Ignore environment variable FILTERED_ROOT because Filter::tee is not available';
 				}
-				my $dir = dirname($ENV{FILTERED_ROOT}.'/'.$asfile);
-				File::Path::make_path($dir) if ! -d $dir;
-				$_ .= "; use Filter::tee '".$ENV{FILTERED_ROOT}.'/'.$asfile."'";
 			}
 			$_ .= ";\n";
 			$_[1] = 0;
@@ -274,7 +278,7 @@ Rest of the options are passed to C<import> of filtered module.
 
 =head1 DEBUG
 
-If environment variable C<FILTERED_ROOT> is specified, filtered results are stored under the directory.
+If L<Filter::tee> is available and environment variable C<FILTERED_ROOT> is specified, filtered results are stored under the directory.
 Assuming the filtered module name is C<Filtered::Target>, the filtered result is stored as C<FILTERED_ROOT/Filtered/Target.pm>.
 
 =head1 CAVEATS
diff --git a/t/debug.pl b/t/debug.pl
index 21187fb..ecbe8e2 100644
--- a/t/debug.pl
+++ b/t/debug.pl
@@ -1,3 +1,7 @@
+BEGIN {
+	require Test::More;
+	Test::More::plan(skip_all => 'Filter::tee is not available') unless eval { require Filter::tee; };
+}
 use Test::More tests => 10;
 use Test::Exception;