merges r23361 from trunk into ruby_1_9_1.

--
* array.c (rb_ary_flatten_bang): returns nil if nothing changed.
  a patch from Marc-Andre Lafortune in [ruby-core:23382].

git-svn-id: http://svn.ruby-lang.org/repos/ruby/branches/ruby_1_9_1@23513 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

4 files changed, 10 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 44bf80fbc..0bfd96dc4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu May  7 16:40:09 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* array.c (rb_ary_flatten_bang): returns nil if nothing changed.
+	  a patch from Marc-Andre Lafortune in [ruby-core:23382].
+
 Thu May  7 14:26:14 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* array.c (rb_ary_sample): negative sample number is invalid.
diff --git a/array.c b/array.c
index 330162160..6923b382c 100644
--- a/array.c
+++ b/array.c
@@ -3190,7 +3190,7 @@ rb_ary_flatten_bang(int argc, VALUE *argv, VALUE ary)
 
     rb_scan_args(argc, argv, "01", &lv);
     if (!NIL_P(lv)) level = NUM2INT(lv);
-    if (level == 0) return ary;
+    if (level == 0) return Qnil;
 
     result = flatten(ary, level, &mod);
     if (mod == 0) return Qnil;
diff --git a/test/ruby/test_array.rb b/test/ruby/test_array.rb
index 384ce239f..372e72738 100644
--- a/test/ruby/test_array.rb
+++ b/test/ruby/test_array.rb
@@ -736,11 +736,14 @@ class TestArray < Test::Unit::TestCase
 
     a5 = @cls[ a1, @cls[], a3 ]
     assert_equal(@cls[1, 2, 3, 4, 5, 6], a5.flatten!)
+    assert_nil(a5.flatten!(0), '[ruby-core:23382]')
     assert_equal(@cls[1, 2, 3, 4, 5, 6], a5)
 
     assert_equal(@cls[], @cls[].flatten)
     assert_equal(@cls[], 
                  @cls[@cls[@cls[@cls[],@cls[]],@cls[@cls[]],@cls[]],@cls[@cls[@cls[]]]].flatten)
+
+    assert_nil(@cls[].flatten!(0), '[ruby-core:23382]')
   end
 
   def test_flatten_with_callcc
diff --git a/version.h b/version.h
index ae7c2f009..435c7a974 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "1.9.1"
 #define RUBY_RELEASE_DATE "2009-05-12"
-#define RUBY_PATCHLEVEL 130
+#define RUBY_PATCHLEVEL 131
 #define RUBY_VERSION_MAJOR 1
 #define RUBY_VERSION_MINOR 9
 #define RUBY_VERSION_TEENY 1