IO#readpartial rejects bad args

Sometimes a sleepy developer will want to swap read_nonblock
for readpartial forget to remove "exception: false"

* io.c (io_getpartial): remove unused kwarg from template
* test/ruby/test_io.rb (test_readpartial_bad_args): new
  [Bug #11885]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53329 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Sun Dec 27 15:14:20 2015  Eric Wong  <e@80x24.org>
+
+	* io.c (io_getpartial): remove unused kwarg from template
+	* test/ruby/test_io.rb (test_readpartial_bad_args): new
+	  [Bug #11885]
+
 Sun Dec 27 11:50:53 2015  Kuniaki IGARASHI  <igaiga@gmail.com>
 
 	* test/ruby/test_string.rb (test_rstrip, test_lstrip): Add tests

io.c

@@ -2506,7 +2506,7 @@ io_getpartial(int argc, VALUE *argv, VALUE io, VALUE opts, int nonblock)
     long n, len;
     struct read_internal_arg arg;
 
-    rb_scan_args(argc, argv, "11:", &length, &str, NULL);
+    rb_scan_args(argc, argv, "11", &length, &str);
 
     if ((len = NUM2LONG(length)) < 0) {
 	rb_raise(rb_eArgError, "negative length %ld given", len);

test/ruby/test_io.rb

@@ -3186,6 +3186,17 @@ End
     }
   end
 
+  def test_readpartial_bad_args
+    IO.pipe do |r, w|
+      w.write '.'
+      buf = String.new
+      assert_raise(ArgumentError) { r.readpartial(1, buf, exception: false) }
+      assert_raise(TypeError) { r.readpartial(1, exception: false) }
+      assert_equal [[r],[],[]], IO.select([r], nil, nil, 1)
+      assert_equal '.', r.readpartial(1)
+    end
+  end
+
   def test_sysread_unlocktmp_ensure
     bug8669 = '[ruby-core:56121] [Bug #8669]'