don't hang if all packages are hidden

2 files changed, 32 insertions, 2 deletions

diff --git a/lib/circular/require.pm b/lib/circular/require.pm
index b7f71c2..234be83 100644
--- a/lib/circular/require.pm
+++ b/lib/circular/require.pm
@@ -62,8 +62,12 @@ sub _require {
         my $depth = 0;
         my $caller;
 
-        $caller = caller( $depth++ )
-            while !$caller || grep { m/^$caller$/ } @hide;
+        do {
+            $caller = caller($depth++)
+        } while defined($caller) && grep { m/^$caller$/ } @hide;
+
+        $caller = '<unknown package>'
+            unless defined $caller;
 
         warn "Circular require detected: $string_file (from $caller)\n";
     }
diff --git a/t/hide_middleman3.t b/t/hide_middleman3.t
new file mode 100644
index 0000000..bbd920f
--- /dev/null
+++ b/t/hide_middleman3.t
@@ -0,0 +1,26 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+use lib 't/hide_middleman';
+use Test::More;
+
+no circular::require -hide => [
+    qw(base Foo Bar main circular::require),
+    (map { my $m = $_; $m =~ s+/+::+g; $m =~ s/\.pm$//; $m } keys %INC),
+];
+
+my @warnings;
+
+{
+    $SIG{__WARN__} = sub { push @warnings => @_ };
+
+    use_ok( 'Foo' );
+}
+
+is_deeply(
+    \@warnings,
+    ["Circular require detected: Foo.pm (from <unknown package>)\n"],
+    "don't loop infinitely if all packages are hidden"
+);
+
+done_testing;