numeric.c: check keyword arguments

* numeric.c (num_step_scan_args): check keyword arguments and fail
  if they conflict with positional arguments.
  [ruby-dev:48177] [Bug #9811]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45861 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Wed May  7 17:24:07 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* numeric.c (num_step_scan_args): check keyword arguments and fail
+	  if they conflict with positional arguments.
+	  [ruby-dev:48177] [Bug #9811]
+
 Wed May  7 12:06:14 2014  Koichi Sasada  <ko1@atdot.net>
 
 	* benchmark/driver.rb: remove debug output and output results into

numeric.c

@@ -1867,8 +1867,19 @@ num_step_scan_args(int argc, const VALUE *argv, VALUE *to, VALUE *step)
 
     argc = rb_scan_args(argc, argv, "02:", to, step, &hash);
     if (!NIL_P(hash)) {
-	*step = rb_hash_aref(hash, sym_by);
-	*to = rb_hash_aref(hash, sym_to);
+	ID keys[2];
+	VALUE values[2];
+	keys[0] = sym_to;
+	keys[1] = sym_by;
+	rb_get_kwargs(hash, keys, 0, 2, values);
+	if (values[0] != Qundef) {
+	    if (argc > 0) rb_raise(rb_eArgError, "to is given twice");
+	    *to = values[0];
+	}
+	if (values[1] != Qundef) {
+	    if (argc > 1) rb_raise(rb_eArgError, "step is given twice");
+	    *step = values[1];
+	}
     }
     else {
 	/* compatibility */

test/ruby/test_numeric.rb

@@ -268,6 +268,14 @@ class TestNumeric < Test::Unit::TestCase
     assert_nothing_raised { 1.step(by: nil) }
     assert_nothing_raised { 1.step(by: nil).size }
 
+    bug9811 = '[ruby-dev:48177] [Bug #9811]'
+    assert_raise(ArgumentError, bug9811) { 1.step(10, foo: nil) {} }
+    assert_raise(ArgumentError, bug9811) { 1.step(10, foo: nil).size }
+    assert_raise(ArgumentError, bug9811) { 1.step(10, to: 11) {} }
+    assert_raise(ArgumentError, bug9811) { 1.step(10, to: 11).size }
+    assert_raise(ArgumentError, bug9811) { 1.step(10, 1, by: 11) {} }
+    assert_raise(ArgumentError, bug9811) { 1.step(10, 1, by: 11).size }
+
     assert_equal(bignum*2+1, (-bignum).step(bignum, 1).size)
     assert_equal(bignum*2, (-bignum).step(bignum-1, 1).size)