merges r30122 from trunk into ruby_1_9_2.

--
	* io.c (io_read): duplicate string if shared. [ruby-dev:42719]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_2@30317 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 9 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 2e9c65f888..852f43a1c6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Dec  7 22:37:15 2010  Masaya Tarui  <tarui@ruby-lnag.org>
+
+	* io.c (io_read): duplicate string if shared. [ruby-dev:42719]
+
 Tue Dec  7 21:59:37 2010  Kouhei Sutou  <kou@cozmixng.org>
 
 	* lib/rexml/light/node.rb: remove circular require.
diff --git a/io.c b/io.c
index 79c3024538..474562a944 100644
--- a/io.c
+++ b/io.c
@@ -2157,7 +2157,10 @@ io_read(int argc, VALUE *argv, VALUE io)
     rb_scan_args(argc, argv, "02", &length, &str);
 
     if (NIL_P(length)) {
-	if (!NIL_P(str)) StringValue(str);
+	if (!NIL_P(str)){
+	    StringValue(str);
+	    rb_str_modify(str);
+	}
 	GetOpenFile(io, fptr);
 	rb_io_check_char_readable(fptr);
 	return read_all(fptr, remain_size(fptr), str);
diff --git a/version.h b/version.h
index d96f840a0d..556c99046b 100644
--- a/version.h
+++ b/version.h
@@ -1,5 +1,5 @@
 #define RUBY_VERSION "1.9.2"
-#define RUBY_PATCHLEVEL 122
+#define RUBY_PATCHLEVEL 123
 #define RUBY_VERSION_MAJOR 1
 #define RUBY_VERSION_MINOR 9
 #define RUBY_VERSION_TEENY 1