string.c: compare with to_str

* string.c (rb_str_cmp_m): try to compare with to_str result if
  possible before calling <=> method.  [ruby-core:49279] [Bug #7342]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38044 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,4 +1,7 @@
-Fri Nov 30 17:43:45 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Fri Nov 30 17:43:50 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* string.c (rb_str_cmp_m): try to compare with to_str result if
+	  possible before calling <=> method.  [ruby-core:49279] [Bug #7342]
 
 	* string.c (rb_str_cmp_m): use rb_check_funcall instead of respond_to
 	  and call.

string.c

@@ -2385,9 +2385,9 @@ rb_str_cmp_m(VALUE str1, VALUE str2)
     int result;
 
     if (!RB_TYPE_P(str2, T_STRING)) {
-	VALUE tmp;
-	if (!rb_respond_to(str2, rb_intern("to_str"))) {
-	    return Qnil;
+	VALUE tmp = rb_check_funcall(str2, rb_intern("to_str"), 0, 0);
+	if (RB_TYPE_P(tmp, T_STRING)) {
+	    result = rb_str_cmp(str1, tmp);
 	}
 	else if ((tmp = rb_check_funcall(str2, rb_intern("<=>"), 1, &str1)) ==
 		 Qundef) {

test/ruby/test_string.rb

@@ -170,8 +170,9 @@ class TestString < Test::Unit::TestCase
 
     o = Object.new
     def o.to_str; "bar"; end
-    assert_nil("foo" <=> o)
+    assert_equal(1, "foo" <=> o)
 
+    class << o;remove_method :to_str;end
     def o.<=>(x); nil; end
     assert_nil("foo" <=> o)