* io.c (rb_io_readlines, rb_io_each_line): limit must not be zero.

a patch from Tomoyuki Chikanaga at [ruby-dev:42538].  #4024

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@29694 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Fri Nov  5 00:39:00 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* io.c (rb_io_readlines, rb_io_each_line): limit must not be zero.
+	  a patch from Tomoyuki Chikanaga at [ruby-dev:42538].  #4024
+
 Fri Nov  5 00:14:15 2010  Aaron Patterson <aaron@tenderlovemaking.com>
 
 	* ext/fiddle/extconf.rb: fixing ffi library location on windows.

io.c

@@ -2724,6 +2724,8 @@ rb_io_readlines(int argc, VALUE *argv, VALUE io)
     long limit;
 
     prepare_getline_args(argc, argv, &rs, &limit, io);
+    if (limit == 0)
+	rb_raise(rb_eArgError, "invalid limit: 0 for readlines");
     ary = rb_ary_new();
     while (!NIL_P(line = rb_io_getline_1(rs, limit, io))) {
 	rb_ary_push(ary, line);
@@ -2773,6 +2775,8 @@ rb_io_each_line(int argc, VALUE *argv, VALUE io)
 
     RETURN_ENUMERATOR(io, argc, argv);
     prepare_getline_args(argc, argv, &rs, &limit, io);
+    if (limit == 0)
+	rb_raise(rb_eArgError, "invalid limit: 0 for each_line");
     while (!NIL_P(str = rb_io_getline_1(rs, limit, io))) {
 	rb_yield(str);
     }

test/ruby/test_io.rb

@@ -1702,4 +1702,24 @@ End
       GC.start
     end
   end
+
+  def test_readlines_limit_0
+    bug4024 = '[ruby-dev:42538]'
+    t = make_tempfile
+    open(t.path, "r") do |io|
+      assert_raise(ArgumentError, bug4024) do
+        io.readlines(0)
+      end
+    end
+  end
+
+  def test_each_line_limit_0
+    bug4024 = '[ruby-dev:42538]'
+    t = make_tempfile
+    open(t.path, "r") do |io|
+      assert_raise(ArgumentError, bug4024) do
+        io.each_line(0).next
+      end
+    end
+  end
 end