merge revision(s) 63823,63839: [Backport #14890]

	time.c: [DOC] Time#localtime

	* time.c: state that Time#localtime does nothing when nothing
	  changes.  [ruby-core:87675] [Bug #14880]

	skip test_localtime_zone if force_tz_test is false

	For example Solaris
	https://rubyci.org/logs/rubyci.s3.amazonaws.com/unstable10x/ruby-trunk/log/20180703T091803Z.fail.html.gz

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@66780 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

spec/ruby/core/time/localtime_spec.rb

@@ -90,6 +90,19 @@
 
       t.utc_offset.should == -18000
     end
+
+    it "does nothing if already in a local time zone" do
+      time = with_timezone("America/New_York") do
+        break Time.new(2005, 2, 27, 22, 50, 0)
+      end
+      zone = time.zone
+
+      with_timezone("Europe/Amsterdam") do
+        time.localtime
+      end
+
+      time.zone.should == zone
+    end
   end
 
   describe "with an argument that responds to #to_str" do

test/ruby/test_time_tz.rb

@@ -107,6 +107,18 @@ def assert_time_constructor(tz, expected, method, args, message=nil)
     assert_equal(expected, real, m)
   end
 
+  def test_localtime_zone
+    t = with_tz("America/Los_Angeles") {
+      Time.local(2000, 1, 1)
+    }
+    skip "force_tz_test is false on this environment" unless t
+    z1 = t.zone
+    z2 = with_tz(tz="Asia/Singapore") {
+      t.localtime.zone
+    }
+    assert_equal(z2, z1)
+  end
+
   def test_america_los_angeles
     with_tz(tz="America/Los_Angeles") {
       assert_time_constructor(tz, "2007-03-11 03:00:00 -0700", :local, [2007,3,11,2,0,0])

time.c

@@ -3410,6 +3410,9 @@ time_localtime(VALUE time)
  *
  *     t.localtime("+09:00")                   #=> 2000-01-02 05:15:01 +0900
  *     t.utc?                                  #=> false
+ *
+ *  If +utc_offset+ is not given and _time_ is local time, just return
+ *  the receiver.
  */
 
 static VALUE

version.h

@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.5.4"
 #define RUBY_RELEASE_DATE "2019-01-10"
-#define RUBY_PATCHLEVEL 126
+#define RUBY_PATCHLEVEL 127
 
 #define RUBY_RELEASE_YEAR 2019
 #define RUBY_RELEASE_MONTH 1