merge revision(s) 61517: [Backport #14259]

numeric.c: Fix Integer#pow with a large Fixnum modulo

	* numeric.c: Fix Integer#pow with a large Fixnum modulo
	  [Bug #14259] [ruby-core:84562]

	* test/ruby/test_numeric.rb: add assertions for reproducing this bug.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@61629 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

bignum.c

@@ -7016,7 +7016,9 @@ int_pow_tmp2(VALUE x, VALUE y, long mm, int nega_flg)
         xx = MUL_MODULO(xx, xx, m);
     }
 
-#ifndef DLONG
+#ifdef DLONG
+    tmp = tmp2;
+#else
     tmp = FIX2LONG(tmp2);
 #endif
     if (nega_flg && tmp) {

test/ruby/test_numeric.rb

@@ -400,6 +400,11 @@ class TestNumeric < Test::Unit::TestCase
                  2120078484650058507891187874713297895455.
                     pow(5478118174010360425845660566650432540723,
                         5263488859030795548286226023720904036518))
+
+    assert_equal(12, 12.pow(1, 10000000000), '[Bug #14259]')
+    assert_equal(12, 12.pow(1, 10000000001), '[Bug #14259]')
+    assert_equal(12, 12.pow(1, 10000000002), '[Bug #14259]')
+    assert_equal(17298641040, 12.pow(72387894339363242, 243682743764), '[Bug #14259]')
   end
 
 end

version.h

@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.5.0"
 #define RUBY_RELEASE_DATE "2018-01-06"
-#define RUBY_PATCHLEVEL 7
+#define RUBY_PATCHLEVEL 8
 
 #define RUBY_RELEASE_YEAR 2018
 #define RUBY_RELEASE_MONTH 1