merges r30721 from trunk into ruby_1_9_2.

--
* array.c (rb_ary_join): [].join.encoding must be US-ASCII.
  [ruby-list:47790]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_2@30901 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

4 files changed, 8 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 6bb9fb2b5d..3cba4a4fe7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Jan 29 22:16:26 2011  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* array.c (rb_ary_join): [].join.encoding must be US-ASCII.
+	  [ruby-list:47790]
+
 Fri Jan 28 12:05:48 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* configure.in: Add #include<sys/stat.h> when struct stat is
diff --git a/array.c b/array.c
index d413f3377f..6640a1af28 100644
--- a/array.c
+++ b/array.c
@@ -1643,7 +1643,7 @@ rb_ary_join(VALUE ary, VALUE sep)
     int untrust = FALSE;
     VALUE val, tmp, result;
 
-    if (RARRAY_LEN(ary) == 0) return rb_str_new(0, 0);
+    if (RARRAY_LEN(ary) == 0) return rb_usascii_str_new(0, 0);
     if (OBJ_TAINTED(ary) || OBJ_TAINTED(sep)) taint = TRUE;
     if (OBJ_UNTRUSTED(ary) || OBJ_UNTRUSTED(sep)) untrust = TRUE;
 
diff --git a/test/ruby/test_array.rb b/test/ruby/test_array.rb
index 1816ea1d02..1c80f2d145 100644
--- a/test/ruby/test_array.rb
+++ b/test/ruby/test_array.rb
@@ -890,6 +890,7 @@ class TestArray < Test::Unit::TestCase
     a = @cls[]
     assert_equal("", a.join)
     assert_equal("", a.join(','))
+    assert_equal(Encoding::US_ASCII, a.join.encoding)
 
     $, = ""
     a = @cls[1, 2]
diff --git a/version.h b/version.h
index ad029f603d..7ae81ecfcf 100644
--- a/version.h
+++ b/version.h
@@ -1,5 +1,5 @@
 #define RUBY_VERSION "1.9.2"
-#define RUBY_PATCHLEVEL 178
+#define RUBY_PATCHLEVEL 179
 #define RUBY_VERSION_MAJOR 1
 #define RUBY_VERSION_MINOR 9
 #define RUBY_VERSION_TEENY 1