From f37c8c6a403486522d197d9749ab3c7e7d9105ab Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Fri, 6 Jan 2012 10:28:20 -0600
Subject: not lexical scope, but dynamic scope is close enough i think

---
 lib/circular/require.pm | 26 +++++++++++++----
 t/basic.t               |  4 +--
 t/dynamic.t             | 78 +++++++++++++++++++++++++++++++++++++++++++++++++
 t/dynamic2.t            | 12 ++++++++
 t/dynamic2/Bar.pm       |  5 ++++
 t/dynamic2/Baz.pm       |  3 ++
 t/dynamic2/Foo.pm       |  4 +++
 t/dynamic2/Quux.pm      |  3 ++
 8 files changed, 127 insertions(+), 8 deletions(-)
 create mode 100644 t/dynamic.t
 create mode 100644 t/dynamic2.t
 create mode 100644 t/dynamic2/Bar.pm
 create mode 100644 t/dynamic2/Baz.pm
 create mode 100644 t/dynamic2/Foo.pm
 create mode 100644 t/dynamic2/Quux.pm

diff --git a/lib/circular/require.pm b/lib/circular/require.pm
index 1d9e38d..184c361 100644
--- a/lib/circular/require.pm
+++ b/lib/circular/require.pm
@@ -53,6 +53,17 @@ our $previous_file;
 my $saved_require_hook;
 my @hide;
 
+sub _find_enable_state {
+    my $depth = 0;
+    while (defined(scalar(caller(++$depth)))) {
+        my $hh = (caller($depth))[10];
+        next unless defined $hh;
+        next unless exists $hh->{'circular::require'};
+        return $hh->{'circular::require'};
+    }
+    return 0;
+}
+
 sub _require {
     my ($file) = @_;
     # on 5.8, if a value has both a string and numeric value, require will
@@ -71,11 +82,13 @@ sub _require {
             $caller = $loaded_from{$caller};
         }
 
-        if (@cycle > 1) {
-            warn "Circular require detected:\n  " . join("\n  ", @cycle) . "\n";
-        }
-        else {
-            warn "Circular require detected in $string_file (from unknown file)\n";
+        if (_find_enable_state()) {
+            if (@cycle > 1) {
+                warn "Circular require detected:\n  " . join("\n  ", @cycle) . "\n";
+            }
+            else {
+                warn "Circular require detected in $string_file (from unknown file)\n";
+            }
         }
     }
     local $loaded_from{$string_file} = $previous_file;
@@ -108,6 +121,8 @@ sub import {
     else {
         $stash->remove_package_symbol('&require');
     }
+    # not delete, because we want to see it being explicitly disabled
+    $^H{'circular::require'} = 0;
 }
 
 sub unimport {
@@ -123,6 +138,7 @@ sub unimport {
     $saved_require_hook = $old_require
         if defined($old_require) && $old_require != \&_require;
     $stash->add_package_symbol('&require', \&_require);
+    $^H{'circular::require'} = 1;
 }
 
 sub _mod2pm {
diff --git a/t/basic.t b/t/basic.t
index 44fade4..d0abc8b 100644
--- a/t/basic.t
+++ b/t/basic.t
@@ -4,9 +4,7 @@ use warnings;
 use lib 't/basic';
 use Test::More;
 
-use circular::require ();
-
-circular::require->unimport;
+no circular::require;
 
 {
     my $warnings;
diff --git a/t/dynamic.t b/t/dynamic.t
new file mode 100644
index 0000000..455130a
--- /dev/null
+++ b/t/dynamic.t
@@ -0,0 +1,78 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+use Test::More;
+use lib 't/basic';
+
+{
+    no circular::require;
+
+    my $warnings;
+    local $SIG{__WARN__} = sub { $warnings .= $_[0] };
+    use_ok('Foo');
+    is($warnings, "Circular require detected:\n  Foo.pm\n  Baz.pm\n  Foo.pm\nCircular require detected:\n  Baz.pm\n  Bar.pm\n  Baz.pm\n", "correct warnings");
+
+    clear();
+}
+
+{
+    no circular::require;
+    use circular::require;
+
+    my $warnings;
+    local $SIG{__WARN__} = sub { $warnings .= $_[0] };
+    use_ok('Foo');
+    is($warnings, undef, "correct warnings");
+
+    clear();
+}
+
+{
+    no circular::require;
+
+    my $warnings;
+    local $SIG{__WARN__} = sub { $warnings .= $_[0] };
+    use_ok('Foo');
+    is($warnings, "Circular require detected:\n  Foo.pm\n  Baz.pm\n  Foo.pm\nCircular require detected:\n  Baz.pm\n  Bar.pm\n  Baz.pm\n", "correct warnings");
+
+    clear();
+    undef $warnings;
+
+    {
+        use circular::require;
+
+        use_ok('Foo');
+        is($warnings, undef, "correct warnings");
+
+        clear();
+        undef $warnings;
+
+        {
+            no circular::require;
+
+            use_ok('Foo');
+            is($warnings, "Circular require detected:\n  Foo.pm\n  Baz.pm\n  Foo.pm\nCircular require detected:\n  Baz.pm\n  Bar.pm\n  Baz.pm\n", "correct warnings");
+        }
+
+    }
+}
+
+{
+    my $warnings;
+    local $SIG{__WARN__} = sub { $warnings .= $_[0] };
+    use_ok('Foo');
+    is($warnings, undef, "correct warnings");
+
+    clear();
+}
+
+sub clear {
+    for (qw(Foo Bar Baz)) {
+        no strict 'refs';
+        delete $::{$_};
+        delete ${$_ . '::'}{quux};
+        delete $INC{"$_.pm"};
+    }
+}
+
+done_testing;
diff --git a/t/dynamic2.t b/t/dynamic2.t
new file mode 100644
index 0000000..f1fd093
--- /dev/null
+++ b/t/dynamic2.t
@@ -0,0 +1,12 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+use Test::More;
+use lib 't/dynamic2';
+
+my $warnings;
+local $SIG{__WARN__} = sub { $warnings .= $_[0] };
+use_ok('Foo');
+is($warnings, "Circular require detected:\n  Bar.pm\n  Baz.pm\n  Bar.pm\n", "correct warnings");
+
+done_testing;
diff --git a/t/dynamic2/Bar.pm b/t/dynamic2/Bar.pm
new file mode 100644
index 0000000..ebb6a1c
--- /dev/null
+++ b/t/dynamic2/Bar.pm
@@ -0,0 +1,5 @@
+package Bar;
+use Baz;
+use circular::require;
+use Quux;
+1;
diff --git a/t/dynamic2/Baz.pm b/t/dynamic2/Baz.pm
new file mode 100644
index 0000000..c718929
--- /dev/null
+++ b/t/dynamic2/Baz.pm
@@ -0,0 +1,3 @@
+package Baz;
+use Bar;
+1;
diff --git a/t/dynamic2/Foo.pm b/t/dynamic2/Foo.pm
new file mode 100644
index 0000000..29e832a
--- /dev/null
+++ b/t/dynamic2/Foo.pm
@@ -0,0 +1,4 @@
+package Foo;
+no circular::require;
+use Bar;
+1;
diff --git a/t/dynamic2/Quux.pm b/t/dynamic2/Quux.pm
new file mode 100644
index 0000000..1dc5aba
--- /dev/null
+++ b/t/dynamic2/Quux.pm
@@ -0,0 +1,3 @@
+package Quux;
+use Bar;
+1;
-- 
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