diff --git a/ChangeLog b/ChangeLog
index 8178759b24..9df43f2f05 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Nov 19 00:59:31 2004  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* string.c (str_gsub): internal buffer should not be listed by
+	  ObjectSpace.each_object().  [ruby-dev:24919]
+
 Thu Nov 18 23:42:36 2004  Minero Aoki  <aamine@loveruby.net>
 
 	* ext/ripper/depend: Never regenerate lib/ripper/core.rb
diff --git a/string.c b/string.c
index f388d24db6..efa817ea43 100644
--- a/string.c
+++ b/string.c
@@ -2076,6 +2076,9 @@ str_gsub(argc, argv, str, bang)
 
     blen = RSTRING(str)->len + 30; /* len + margin */
     dest = rb_str_new5(str, 0, blen);
+    if (bang) {
+	RBASIC(dest)->klass = 0;
+    }
     buf = RSTRING(dest)->ptr;
     bp = buf;
     sp = cp = RSTRING(str)->ptr;
diff --git a/test/ruby/test_stringchar.rb b/test/ruby/test_stringchar.rb
index 943b656510..34934e87bd 100644
--- a/test/ruby/test_stringchar.rb
+++ b/test/ruby/test_stringchar.rb
@@ -113,4 +113,54 @@ EOS
     }
     assert_equal(0, a.size)
   end
+
+  def test_bang
+    s = "aBc"
+    s.upcase
+    assert_equal("aBc", s)
+    s.upcase!
+    assert_equal("ABC", s)
+
+    s = "aBc"
+    s.downcase
+    assert_equal("aBc", s)
+    s.downcase!
+    assert_equal("abc", s)
+
+    s = "aBc"
+    s.swapcase
+    assert_equal("aBc", s)
+    s.swapcase!
+    assert_equal("AbC", s)
+
+    s = "aBc"
+    s.capitalize
+    assert_equal("aBc", s)
+    s.capitalize!
+    assert_equal("Abc", s)
+
+    s = "aBc"
+    s.tr("a-z", "A-Z")
+    assert_equal("aBc", s)
+    s.tr!("a-z", "A-Z")
+    assert_equal("ABC", s)
+
+    s = "aaBBcc"
+    s.tr_s("a-z", "A-Z")
+    assert_equal("aaBBcc", s)
+    s.tr_s!("a-z", "A-Z")
+    assert_equal("ABBC", s)
+
+    s = "aaBBcc"
+    s.squeeze("a-z")
+    assert_equal("aaBBcc", s)
+    s.squeeze!("a-z")
+    assert_equal("aBBc", s)
+
+    s = "aaBBcc"
+    s.delete("a-z")
+    assert_equal("aaBBcc", s)
+    s.delete!("a-z")
+    assert_equal("BB", s)
+  end
 end