fix vtm_add_offset yday on last day of year.

* time.c (vtm_add_offset): Fix yday on last day of year.
  [ruby-core:72878] [Bug #11994] Fixed by Andrew White.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56599 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Sat Nov  5 23:46:03 2016  Tanaka Akira  <akr@fsij.org>
+
+	* time.c (vtm_add_offset): Fix yday on last day of year.
+	  [ruby-core:72878] [Bug #11994] Fixed by Andrew White.
+
 Sat Nov  5 23:30:41 2016  Shugo Maeda  <shugo@ruby-lang.org>
 
 	* lib/net/http.rb (Net::HTTP.post): new convenience method to send

test/ruby/test_time.rb

@@ -1072,4 +1072,21 @@ class TestTime < Test::Unit::TestCase
     assert_equal now2, now3
     assert_equal now2.zone, now3.zone
   end
+
+  def test_strftime_yearday_on_last_day_of_year
+    t = Time.utc(2015, 12, 31, 0, 0, 0)
+    assert_equal("365", t.strftime("%j"))
+    t = Time.utc(2016, 12, 31, 0, 0, 0)
+    assert_equal("366", t.strftime("%j"))
+
+    t = Time.utc(2015, 12, 30, 20, 0, 0).getlocal("+05:00")
+    assert_equal("365", t.strftime("%j"))
+    t = Time.utc(2016, 12, 30, 20, 0, 0).getlocal("+05:00")
+    assert_equal("366", t.strftime("%j"))
+
+    t = Time.utc(2016, 1, 1, 1, 0, 0).getlocal("-05:00")
+    assert_equal("365", t.strftime("%j"))
+    t = Time.utc(2017, 1, 1, 1, 0, 0).getlocal("-05:00")
+    assert_equal("366", t.strftime("%j"))
+  end
 end

time.c

@@ -1889,7 +1889,7 @@ vtm_add_offset(struct vtm *vtm, VALUE off)
                 vtm->mday = 31;
                 vtm->mon = 12; /* December */
                 vtm->year = sub(vtm->year, INT2FIX(1));
-                vtm->yday = leap_year_v_p(vtm->year) ? 365 : 364;
+                vtm->yday = leap_year_v_p(vtm->year) ? 366 : 365;
             }
             else if (vtm->mday == 1) {
                 const int *days_in_month = leap_year_v_p(vtm->year) ?