random.c: fix error message

* random.c (rb_random_ulong_limited): fix error message for negative
  value.  [ruby-dev:47061] [Bug #7903]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39376 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Fri Feb 22 12:46:41 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* random.c (rb_random_ulong_limited): fix error message for negative
+	  value.  [ruby-dev:47061] [Bug #7903]
+
 Fri Feb 22 11:36:45 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* test/test_rbconfig.rb (TestRbConfig): skip user defined values by

internal.h

@@ -168,6 +168,7 @@ int rb_num_to_uint(VALUE val, unsigned int *ret);
 VALUE num_interval_step_size(VALUE from, VALUE to, VALUE step, int excl);
 int ruby_float_step(VALUE from, VALUE to, VALUE step, int excl);
 double ruby_float_mod(double x, double y);
+int rb_num_negative_p(VALUE);
 
 /* object.c */
 VALUE rb_obj_equal(VALUE obj1, VALUE obj2);

numeric.c

@@ -185,6 +185,12 @@ negative_int_p(VALUE num)
     return RTEST(rb_funcall(num, mid, 1, INT2FIX(0)));
 }
 
+int
+rb_num_negative_p(VALUE num)
+{
+    return negative_int_p(num);
+}
+
 /*
  *  call-seq:
  *     num.coerce(numeric)  ->  array

random.c

@@ -947,9 +947,13 @@ rb_random_ulong_limited(VALUE obj, unsigned long limit)
 {
     rb_random_t *rnd = try_get_rnd(obj);
     if (!rnd) {
+	extern int rb_num_negative_p(VALUE);
 	VALUE lim = ULONG2NUM(limit);
 	VALUE v = rb_funcall2(obj, id_rand, 1, &lim);
 	unsigned long r = NUM2ULONG(v);
+	if (rb_num_negative_p(v)) {
+	    rb_raise(rb_eRangeError, "random number too small %ld", r);
+	}
 	if (r > limit) {
 	    rb_raise(rb_eRangeError, "random number too big %ld", r);
 	}

test/ruby/test_rand.rb

@@ -1,4 +1,5 @@
 require 'test/unit'
+require_relative 'envutil'
 
 class TestRand < Test::Unit::TestCase
   def assert_random_int(ws, m, init = 0)
@@ -514,4 +515,18 @@ END
       l.call
     end
   end
+
+  def test_random_ulong_limited
+    def (gen = Object.new).rand(*) 1 end
+    assert_equal([2], (1..100).map {[1,2,3].sample(random: gen)}.uniq)
+
+    def (gen = Object.new).rand(*) 100 end
+    e = assert_raise(RangeError) {[1,2,3].sample(random: gen)}
+    assert_match(/big 100\z/, e.message)
+
+    bug7903 = '[ruby-dev:47061] [Bug #7903]'
+    def (gen = Object.new).rand(*) -1 end
+    e = assert_raise(RangeError) {[1,2,3].sample(random: gen)}
+    assert_match(/small -1\z/, e.message, bug7903)
+  end
 end