diff --git a/ChangeLog b/ChangeLog
index 020214f545..eafe478b3b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+Fri Feb 29 02:50:07 2008  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* string.c (str_new): remove encoding assumption of empty string.
+
+	* hash.c ( rb_f_getenv, env_fetch, env_inspect): result of ENV should
+	  be always ASCII-8BIT.
+
+	* object.c (nil_to_s): nil.to_s should be US-ASCII.
+
 Fri Feb 29 02:24:22 2008  Hidetoshi NAGAI  <nagai@ai.kyutech.ac.jp>
 
 	* ext/tk/lib/tk.rb: forgot to update RELEASE_DATE
diff --git a/hash.c b/hash.c
index 53711b2cc2..578e4cd395 100644
--- a/hash.c
+++ b/hash.c
@@ -1826,7 +1826,7 @@ rb_f_getenv(VALUE obj, VALUE name)
 	if (strcmp(nam, PATH_ENV) == 0 && !rb_env_path_tainted())
 #endif
 	{
-	    VALUE str = rb_usascii_str_new2(env);
+	    VALUE str = rb_str_new2(env);
 
 	    rb_obj_freeze(str);
 	    return str;
@@ -1867,7 +1867,7 @@ env_fetch(int argc, VALUE *argv)
 #else
     if (strcmp(nam, PATH_ENV) == 0 && !rb_env_path_tainted())
 #endif
-	return rb_usascii_str_new2(env);
+	return rb_str_new2(env);
     return env_str_new2(env);
 }
 
@@ -2244,7 +2244,7 @@ env_inspect(void)
 	    rb_str_buf_cat2(str, "\"");
 	    rb_str_buf_cat(str, *env, s-*env);
 	    rb_str_buf_cat2(str, "\"=>");
-	    i = rb_inspect(rb_usascii_str_new2(s+1));
+	    i = rb_inspect(rb_str_new2(s+1));
 	    rb_str_buf_append(str, i);
 	}
 	env++;
diff --git a/object.c b/object.c
index 2dc87610da..1585b87feb 100644
--- a/object.c
+++ b/object.c
@@ -808,7 +808,7 @@ nil_to_f(VALUE obj)
 static VALUE
 nil_to_s(VALUE obj)
 {
-    return rb_str_new(0, 0);
+    return rb_usascii_str_new(0, 0);
 }
 
 /*
diff --git a/string.c b/string.c
index 7b65a6dc14..7c80a84d96 100644
--- a/string.c
+++ b/string.c
@@ -365,9 +365,6 @@ str_new(VALUE klass, const char *ptr, long len)
     if (ptr) {
 	memcpy(RSTRING_PTR(str), ptr, len);
     }
-    if (len == 0) {
-	ENCODING_CODERANGE_SET(str, rb_usascii_encindex(), ENC_CODERANGE_7BIT);
-    }
     STR_SET_LEN(str, len);
     RSTRING_PTR(str)[len] = '\0';
     return str;
diff --git a/version.h b/version.h
index 5fd795113b..1e56af9eb9 100644
--- a/version.h
+++ b/version.h
@@ -1,7 +1,7 @@
 #define RUBY_VERSION "1.9.0"
-#define RUBY_RELEASE_DATE "2008-02-28"
+#define RUBY_RELEASE_DATE "2008-02-29"
 #define RUBY_VERSION_CODE 190
-#define RUBY_RELEASE_CODE 20080228
+#define RUBY_RELEASE_CODE 20080229
 #define RUBY_PATCHLEVEL 0
 
 #define RUBY_VERSION_MAJOR 1
@@ -9,7 +9,7 @@
 #define RUBY_VERSION_TEENY 0
 #define RUBY_RELEASE_YEAR 2008
 #define RUBY_RELEASE_MONTH 2
-#define RUBY_RELEASE_DAY 28
+#define RUBY_RELEASE_DAY 29
 
 #ifdef RUBY_EXTERN
 RUBY_EXTERN const char ruby_version[];