rational.c: infinity in power

* rational.c (nurat_expt): return Infinity due to overflow.
  [ruby-core:79686] [Bug #13242]:

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57688 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 12 insertions, 0 deletions

diff --git a/numeric.c b/numeric.c
index 65edfec205..16cdbb261a 100644
--- a/numeric.c
+++ b/numeric.c
@@ -3913,6 +3913,8 @@ int_pow(long x, unsigned long y)
 		VALUE v;
 	      bignum:
 		v = rb_big_pow(rb_int2big(x), LONG2NUM(y));
+		if (RB_FLOAT_TYPE_P(v)) /* infinity due to overflow */
+		    return v;
 		if (z != 1) v = rb_big_mul(rb_int2big(neg ? -z : z), v);
 		return v;
 	    }
diff --git a/rational.c b/rational.c
index 13c44f7925..e779505fd0 100644
--- a/rational.c
+++ b/rational.c
@@ -1042,6 +1042,10 @@ nurat_expt(VALUE self, VALUE other)
 		num = ONE;
 		den = ONE;
 	    }
+	    if (RB_FLOAT_TYPE_P(num)) { /* infinity due to overflow */
+		if (RB_FLOAT_TYPE_P(den)) return DBL2NUM(NAN);
+		return num;
+	    }
 	    return f_rational_new2(CLASS_OF(self), num, den);
 	}
     }
diff --git a/test/ruby/test_rational.rb b/test/ruby/test_rational.rb
index 0a400edea2..c1e7d824d1 100644
--- a/test/ruby/test_rational.rb
+++ b/test/ruby/test_rational.rb
@@ -955,6 +955,12 @@ class Rational_Test < Test::Unit::TestCase
     assert_raise(ZeroDivisionError, bug5713) { Rational(0, 1) ** Rational(-2,3) }
   end
 
+  def test_power_overflow
+    bug = '[ruby-core:79686] [Bug #13242]: Infinity due to overflow'
+    x = EnvUtil.suppress_warning {4r**40000000}
+    assert_predicate x, :infinite?, bug
+  end
+
   def test_positive_p
     assert_predicate(1/2r, :positive?)
     assert_not_predicate(-1/2r, :positive?)