Revert Utils::WinTZ upgrade and lock to TZInfo-1.x (#7562)

Revert "Add missing divider in upgrading-guide"
This reverts commit d8c745ca30.

Revert "Update history to reflect merge of #7521"
This reverts commit 7ee2e26d6c.

Revert "Upgrade WinTZ utility to use TZInfo-2.0"
This reverts commit 13cbef4221.

Lock use of `tzinfo` gem to v1.x

Gemfile

@@ -84,7 +84,7 @@ group :jekyll_optional_dependencies do
   # Windows and JRuby does not include zoneinfo files, so bundle the tzinfo-data gem
   # and associated library
   install_if -> { RUBY_PLATFORM =~ %r!mingw|mswin|java! } do
-    gem "tzinfo", "~> 2.0"
+    gem "tzinfo", "~> 1.2"
     gem "tzinfo-data"
   end
 end

History.markdown

@@ -134,7 +134,6 @@
   * Search Front matter defaults for Page objects with relative_path (#7261)
   * Support for binary operators in where_exp filter (#6998)
   * Configure cache_dir (#7232)
-  * Upgrade WinTZ utility to use TZInfo-2.0 (#7521)
 
 ### Major Enhancements
 

docs/_docs/upgrading/3-to-4.md

@@ -48,22 +48,6 @@ you can invoke *`Liquid::Template`* directly:
 
 ---
 
-### Timezone in Windows
-
-Timezone handling for Jekyll on Windows now requires `tzinfo-2.0` and above.
-Simply add / update the gem listing in your `Gemfile`:
-
-```ruby
-# Gemfile
-
-# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
-# and associated library.
-gem "tzinfo-data", platforms: [:mingw, :mswin, :x64_mingw, :jruby]
-gem "tzinfo", "~> 2.0"
-```
-
----
-
 ### Exclusion changes
 
 We've enhanced our default exclusion array. It now looks like the following:

lib/jekyll/commands/new.rb

@@ -92,7 +92,7 @@ module Jekyll
             # Windows and JRuby does not include zoneinfo files, so bundle the tzinfo-data gem
             # and associated library.
             install_if -> { RUBY_PLATFORM =~ %r!mingw|mswin|java! } do
-              gem "tzinfo", "~> 2.0"
+              gem "tzinfo", "~> 1.2"
               gem "tzinfo-data"
             end
 

lib/jekyll/utils/win_tz.rb

@@ -13,20 +13,16 @@ module Jekyll
       # Returns a string that ultimately re-defines ENV["TZ"] in Windows
       def calculate(timezone)
         External.require_with_graceful_fail("tzinfo") unless defined?(TZInfo)
-        difference = TZInfo::Timezone.get(timezone).now.utc_offset
+        tz = TZInfo::Timezone.get(timezone)
+        difference = Time.now.to_i - tz.now.to_i
         #
         # 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
-        if difference.negative?
-          offset = "-"
-          sign   = "+"
-        else
-          offset = "+"
-          sign   = "-"
-        end
+        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.