From 6cc784a12707d517139481a0a67ca84a02eb4690 Mon Sep 17 00:00:00 2001
From: Hiroshi Shirosaki <h.shirosaki@gmail.com>
Date: Mon, 19 Nov 2012 22:25:22 +0900
Subject: [PATCH] Fix cache validity check of require

If #pop or #shift has been called against $: or $", the array will be
still shared with the snapshot. We check array length for cache
validity.
---
 array.c                   |   11 +++++++----
 test/ruby/test_require.rb |   31 +++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/array.c b/array.c
index 25fd829..9371ef7 100644
--- a/array.c
+++ b/array.c
@@ -351,13 +351,16 @@ rb_ary_frozen_p(VALUE ary)
    e.g. rb_ary_replace) and check later whether the array has been
    modified from the snapshot.  The snapshot is cheap, though if
    something does modify the array it will pay the cost of copying
-   it. */
+   it.  If Array#pop or Array#shift has been called, the array will
+   be still shared with the snapshot, but the array length will
+   differ. */
 VALUE
 rb_ary_shared_with_p(VALUE ary1, VALUE ary2)
 {
-    if (!ARY_EMBED_P(ary1) && ARY_SHARED_P(ary1)
-     && !ARY_EMBED_P(ary2) && ARY_SHARED_P(ary2)
-     && RARRAY(ary1)->as.heap.aux.shared == RARRAY(ary2)->as.heap.aux.shared) {
+    if (!ARY_EMBED_P(ary1) && ARY_SHARED_P(ary1) &&
+	!ARY_EMBED_P(ary2) && ARY_SHARED_P(ary2) &&
+	RARRAY(ary1)->as.heap.aux.shared == RARRAY(ary2)->as.heap.aux.shared &&
+	RARRAY(ary1)->as.heap.len == RARRAY(ary2)->as.heap.len) {
 	return Qtrue;
     }
     return Qfalse;
diff --git a/test/ruby/test_require.rb b/test/ruby/test_require.rb
index 36d7c78..f112140 100644
--- a/test/ruby/test_require.rb
+++ b/test/ruby/test_require.rb
@@ -545,4 +545,35 @@ class TestRequire < Test::Unit::TestCase
       }
     }
   end
+
+  def assert_require_with_shared_array(add, del)
+    bug7383 = '[ruby-core:49518]'
+    Dir.mktmpdir {|tmp|
+      Dir.chdir(tmp) {
+        open("foo.rb", "w") {}
+        Dir.mkdir("a")
+        open(File.join("a", "bar.rb"), "w") {}
+        assert_in_out_err([], <<-INPUT, %w(:ok), [], bug7383)
+          $:.#{add} "#{tmp}"
+          $:.#{add} "#{tmp}/a"
+          require "foo"
+          $:.#{del}
+          # Expanded load path cache should be rebuilt.
+          begin
+            require "bar"
+          rescue LoadError
+            p :ok
+          end
+        INPUT
+      }
+    }
+  end
+
+  def test_require_with_array_pop
+    assert_require_with_shared_array("push", "pop")
+  end
+
+  def test_require_with_array_shift
+    assert_require_with_shared_array("unshift", "shift")
+  end
 end
-- 
1.7.10.2 (Apple Git-33)