* string.c (rb_str_aref): "abc"[3] should not return an empty

  string but nil.  [ruby-dev:28786]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@10363 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 6 insertions, 0 deletions

diff --git a/string.c b/string.c
index f254915f9b..136235580c 100644
--- a/string.c
+++ b/string.c
@@ -1478,6 +1478,12 @@ rb_str_aref(VALUE str, VALUE indx)
 	idx = FIX2LONG(indx);
 
       num_index:
+	if (idx < 0) {
+	    idx = RSTRING(str)->len + idx;
+	}
+	if (idx < 0 || RSTRING(str)->len <= idx) {
+	    return Qnil;
+	}
 	return rb_str_substr(str, idx, 1);
 
       case T_REGEXP: