Support both tzinfo v1 and v2 alongwith non-half hour offsets.

Gemfile

@@ -32,6 +32,8 @@ group :test do
   gem "test-theme", :path => File.expand_path("test/fixtures/test-theme", __dir__)
   gem "test-theme-skinny", :path => File.expand_path("test/fixtures/test-theme-skinny", __dir__)
   gem "test-theme-symlink", :path => File.expand_path("test/fixtures/test-theme-symlink", __dir__)
+  gem "tzinfo", ">= 1", "< 3"
+  gem "tzinfo-data"
 
   if RUBY_ENGINE == "jruby"
     gem "http_parser.rb", "~> 0.6.0"
@@ -81,13 +83,6 @@ group :jekyll_optional_dependencies do
     gem "liquid-c", "~> 4.0"
     gem "yajl-ruby", "~> 1.4"
   end
-
-  # Windows and JRuby does not include zoneinfo files, so bundle the tzinfo-data gem
-  # and associated library
-  platforms :jruby, :mswin, :mingw, :x64_mingw do
-    gem "tzinfo", "~> 1.2"
-    gem "tzinfo-data"
-  end
 end
 
 #

docs/_docs/installation/windows.md

@@ -121,22 +121,14 @@ While 'new' blogs created with Jekyll v3.4 and greater, will have the following
 sites *will* have to update their `Gemfile` (and installed gems) to enable development on Windows:
 
 ```ruby
-# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
-gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
+# Windows and JRuby does not include zoneinfo files, so bundle the tzinfo-data gem
+# and associated library.
+platforms :mingw, :x64_mingw, :mswin, :jruby do
+  gem "tzinfo", ">= 1", "< 3"
+  gem "tzinfo-data"
+end
 ```
 
-<div class="note warning">
-  <h5>TZInfo 2.0 incompatibility</h5>
-  <p>
-    Version 2.0 of the TZInfo library has introduced a change in how timezone offsets are calculated.
-    This will result in incorrect date and time for your posts when the site is built with Jekyll 3.x on Windows.
-  </p>
-  <p>
-    We therefore recommend that you lock the Timezone library to version 1.2 and above by listing
-    <code>gem 'tzinfo', '~> 1.2'</code> in your <code>Gemfile</code>.
-  </p>
-</div>
-
 ## Auto Regeneration
 
 Jekyll uses the `listen` gem to watch for changes when the `--watch` switch is specified during a build or serve.

features/site_configuration.feature

@@ -291,6 +291,28 @@ Feature: Site configuration
       And I should see "Post Layout: <p>content for entry1.</p>\n built at 2013-04-09T09:22:00-10:00" in "_site/2013/04/09/entry1.html"
       And I should see "Post Layout: <p>content for entry2.</p>\n built at 2013-04-09T13:14:00-10:00" in "_site/2013/04/09/entry2.html"
 
+    Scenario: Generate proper dates with explicitly set timezone (using non-half hour offset )
+      Given I have a _layouts directory
+      And I have a page layout that contains "Page Layout: {{ site.posts.size }}"
+      And I have a post layout that contains "Post Layout: {{ content }} built at {{ page.date | date_to_xmlschema }}"
+      And I have an "index.html" page with layout "page" that contains "site index page"
+      And I have a configuration file with:
+        | key         | value           |
+        | timezone    | Australia/Eucla |
+      And I have a _posts directory
+      And I have the following posts:
+        | title     | date                   | layout  | content             |
+        | entry1    | 2013-04-09 23:22 +0400 | post    | content for entry1. |
+        | entry2    | 2013-04-10 03:14 +0400 | post    | content for entry2. |
+      When I run jekyll build
+      Then I should get a zero exit status
+    And the _site directory should exist
+      And I should see "Page Layout: 2" in "_site/index.html"
+      And the "_site/2013/04/10/entry1.html" file should exist
+      And the "_site/2013/04/10/entry2.html" file should exist
+      And I should see "Post Layout: <p>content for entry1.</p>\n built at 2013-04-10T04:07:00\+08:45" in "_site/2013/04/10/entry1.html"
+      And I should see "Post Layout: <p>content for entry2.</p>\n built at 2013-04-10T07:59:00\+08:45" in "_site/2013/04/10/entry2.html"
+
   Scenario: Limit the number of posts generated by most recent date
     Given I have a _posts directory
     And I have a configuration file with:

lib/jekyll/commands/new.rb

@@ -92,7 +92,7 @@ def gemfile_contents
             # Windows and JRuby does not include zoneinfo files, so bundle the tzinfo-data gem
             # and associated library.
             platforms :mingw, :x64_mingw, :mswin, :jruby do
-              gem "tzinfo", "~> 1.2"
+              gem "tzinfo", ">= 1", "< 3"
               gem "tzinfo-data"
             end
 

lib/jekyll/utils/win_tz.rb

@@ -11,64 +11,35 @@ module WinTZ
       # timezone - the IANA Time Zone specified in "_config.yml"
       #
       # Returns a string that ultimately re-defines ENV["TZ"] in Windows
-      def calculate(timezone)
+      def calculate(timezone, now = Time.now)
         External.require_with_graceful_fail("tzinfo") unless defined?(TZInfo)
         tz = TZInfo::Timezone.get(timezone)
-        difference = Time.now.to_i - tz.now.to_i
+
+        #
+        # Use period_for_utc and utc_total_offset instead of
+        # period_for and observed_utc_offset for compatibility with tzinfo v1.
+        offset = tz.period_for_utc(now.getutc).utc_total_offset
+
         #
         # POSIX style definition reverses the offset sign.
         #   e.g. Eastern Standard Time (EST) that is 5Hrs. to the 'west' of Prime Meridian
         #   is denoted as:
         #     EST+5 (or) EST+05:00
         # Reference: http://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html
-        sign = difference.negative? ? "-" : "+"
-        offset = sign == "-" ? "+" : "-" unless difference.zero?
-        #
-        # convert the difference (in seconds) to hours, as a rational number, and perform
-        # a modulo operation on it.
-        modulo = modulo_of(rational_hour(difference))
+        sign = offset.positive? ? "-" : "+"
+
+        rational_hours = offset.abs.to_r / 3600
+        hours = rational_hours.to_i
+        minutes = ((rational_hours - hours) * 60).to_i
+
         #
-        # Format the hour as a two-digit number.
-        # Establish the minutes based on modulo expression.
-        hh = format("%<hour>02d", :hour => absolute_hour(difference).ceil)
-        mm = modulo.zero? ? "00" : "30"
+        # Format the hours and minutes as two-digit numbers.
+        time = format("%<hours>02d:%<minutes>02d", :hours => hours, :minutes => minutes)
 
-        Jekyll.logger.debug "Timezone:", "#{timezone} #{offset}#{hh}:#{mm}"
+        Jekyll.logger.debug "Timezone:", "#{timezone} #{sign}#{time}"
         #
         # Note: The 3-letter-word below doesn't have a particular significance.
-        "WTZ#{sign}#{hh}:#{mm}"
-      end
-
-      private
-
-      # Private: Convert given seconds to an hour as a rational number.
-      #
-      # seconds - supplied as an integer, it is converted to a rational number.
-      # 3600 - no. of seconds in an hour.
-      #
-      # Returns a rational number.
-      def rational_hour(seconds)
-        seconds.to_r / 3600
-      end
-
-      # Private: Convert given seconds to an hour as an absolute number.
-      #
-      # seconds - supplied as an integer, it is converted to its absolute.
-      # 3600 - no. of seconds in an hour.
-      #
-      # Returns an integer.
-      def absolute_hour(seconds)
-        seconds.abs / 3600
-      end
-
-      # Private: Perform a modulo operation on a given fraction.
-      #
-      # fraction - supplied as a rational number, its numerator is divided
-      #            by its denominator and the remainder returned.
-      #
-      # Returns an integer.
-      def modulo_of(fraction)
-        fraction.numerator % fraction.denominator
+        "WTZ#{sign}#{time}"
       end
     end
   end

test/test_win_tz.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require "helper"
+
+class TestWinTz < JekyllUnitTest
+  [["America/New_York", "WTZ+05:00"], ["Europe/Paris", "WTZ-01:00"]].each do |tz, expected|
+    should "use base offset in winter for #{tz}" do
+      result = Jekyll::Utils::WinTZ.calculate(tz, Time.utc(2021, 1, 1))
+      assert_equal expected, result
+    end
+  end
+
+  [["America/New_York", "WTZ+04:00"], ["Europe/Paris", "WTZ-02:00"]].each do |tz, expected|
+    should "apply DST in summer for #{tz}" do
+      result = Jekyll::Utils::WinTZ.calculate(tz, Time.utc(2021, 7, 1))
+      assert_equal expected, result
+    end
+  end
+
+  [["Australia/Eucla", "WTZ-08:45"], ["Pacific/Marquesas", "WTZ+09:30"]].each do |tz, expected|
+    should "handle non zero minutes for #{tz}" do
+      result = Jekyll::Utils::WinTZ.calculate(tz, Time.utc(2021, 1, 1))
+      assert_equal expected, result
+    end
+  end
+
+  should "return zero for UTC" do
+    result = Jekyll::Utils::WinTZ.calculate("UTC")
+    assert_equal "WTZ+00:00", result
+  end
+end