merge revision(s) 57688,57689: [Backport #13242]

	rational.c: infinity in power

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

	* rational.c (nurat_expt): return 0 due to overflow.
	  [ruby-core:79686] [Bug #13242]:

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_4@57911 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

4 files changed, 19 insertions, 1 deletions

diff --git a/numeric.c b/numeric.c
index 28ad30d764..f67b910c1f 100644
--- a/numeric.c
+++ b/numeric.c
@@ -3904,6 +3904,8 @@ 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 8d05342ed5..460f82cfeb 100644
--- a/rational.c
+++ b/rational.c
@@ -1039,6 +1039,14 @@ 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;
+	    }
+	    if (RB_FLOAT_TYPE_P(den)) { /* infinity due to overflow */
+		num = ZERO;
+		den = ONE;
+	    }
 	    return f_rational_new2(CLASS_OF(self), num, den);
 	}
     }
diff --git a/test/ruby/test_rational.rb b/test/ruby/test_rational.rb
index e40de141b5..20989a572e 100644
--- a/test/ruby/test_rational.rb
+++ b/test/ruby/test_rational.rb
@@ -955,6 +955,14 @@ 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
+    x = EnvUtil.suppress_warning {(1/4r)**40000000}
+    assert_equal 0, x, bug
+  end
+
   def test_positive_p
     assert_predicate(1/2r, :positive?)
     assert_not_predicate(-1/2r, :positive?)
diff --git a/version.h b/version.h
index 4efddc7b49..bb6f963b3b 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.4.0"
 #define RUBY_RELEASE_DATE "2017-03-12"
-#define RUBY_PATCHLEVEL 67
+#define RUBY_PATCHLEVEL 68
 
 #define RUBY_RELEASE_YEAR 2017
 #define RUBY_RELEASE_MONTH 3