merges r30648 from trunk into ruby_1_9_2.

--
* string.c (rb_string_value_cstr): rb_str_modify can change
  RSTRING_PTR.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_2@30694 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

5 files changed, 48 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 168325762c..1da731e332 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Jan 25 07:00:52 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* string.c (rb_string_value_cstr): rb_str_modify can change
+	  RSTRING_PTR.
+
 Tue Jan 25 07:48:22 2011  Kazuhiro NISHIYAMA  <zn@mbf.nifty.com>
 
 	* test/ruby/test_thread.rb: remove unused variables.
diff --git a/ext/-test-/string/cstr.c b/ext/-test-/string/cstr.c
new file mode 100644
index 0000000000..d4ff360575
--- /dev/null
+++ b/ext/-test-/string/cstr.c
@@ -0,0 +1,20 @@
+#include "ruby.h"
+
+static VALUE
+bug_str_cstr_term(VALUE str)
+{
+    long len;
+    char *s;
+    rb_str_modify(str);
+    len = RSTRING_LEN(str);
+    RSTRING_PTR(str)[len] = 'x';
+    s = StringValueCStr(str);
+    rb_gc();
+    return INT2NUM(s[len]);
+}
+
+void
+Init_cstr(VALUE klass)
+{
+    rb_define_method(klass, "cstr_term", bug_str_cstr_term, 0);
+}
diff --git a/string.c b/string.c
index 542aaff0ee..368eb63463 100644
--- a/string.c
+++ b/string.c
@@ -1381,7 +1381,11 @@ rb_string_value_cstr(volatile VALUE *ptr)
     if (!s || memchr(s, 0, len)) {
 	rb_raise(rb_eArgError, "string contains null byte");
     }
-    if (s[len]) rb_str_modify(str);
+    if (s[len]) {
+	rb_str_modify(str);
+	s = RSTRING_PTR(str);
+	s[RSTRING_LEN(str)] = 0;
+    }
     return s;
 }
 
diff --git a/test/-ext-/string/test_cstr.rb b/test/-ext-/string/test_cstr.rb
new file mode 100644
index 0000000000..8c0bb136ad
--- /dev/null
+++ b/test/-ext-/string/test_cstr.rb
@@ -0,0 +1,17 @@
+require 'test/unit'
+require "-test-/string/string"
+
+class Test_StringCStr < Test::Unit::TestCase
+  Bug4319 = '[ruby-dev:43094]'
+
+  def test_embed
+    s = Bug::String.new("abcdef")
+    s.set_len(3)
+    assert_equal(0, s.cstr_term, Bug4319)
+  end
+
+  def test_long
+    s = Bug::String.new("abcdef")*100000
+    assert_equal(0, s.cstr_term, Bug4319)
+  end
+end
diff --git a/version.h b/version.h
index d7c3d7886d..1b85269659 100644
--- a/version.h
+++ b/version.h
@@ -1,5 +1,5 @@
 #define RUBY_VERSION "1.9.2"
-#define RUBY_PATCHLEVEL 171
+#define RUBY_PATCHLEVEL 172
 #define RUBY_VERSION_MAJOR 1
 #define RUBY_VERSION_MINOR 9
 #define RUBY_VERSION_TEENY 1