1 files changed, 24 insertions, 17 deletions
diff --git a/activesupport/lib/active_support/core_ext/time/zones.rb b/activesupport/lib/active_support/core_ext/time/zones.rb
index ff90d7ca58..0c5962858e 100644
--- a/activesupport/lib/active_support/core_ext/time/zones.rb
+++ b/activesupport/lib/active_support/core_ext/time/zones.rb
@@ -34,29 +34,36 @@ class Time
     #     end
     #   end
     def zone=(time_zone)
-      Thread.current[:time_zone] = get_zone(time_zone)
+      Thread.current[:time_zone] = find_zone!(time_zone)
     end
 
     # Allows override of <tt>Time.zone</tt> locally inside supplied block; resets <tt>Time.zone</tt> to existing value when done.
     def use_zone(time_zone)
-      old_zone, ::Time.zone = ::Time.zone, get_zone(time_zone)
-      yield
-    ensure
-      ::Time.zone = old_zone
+      new_zone = find_zone!(time_zone)
+      begin
+        old_zone, ::Time.zone = ::Time.zone, new_zone
+        yield
+      ensure
+        ::Time.zone = old_zone
+      end
     end
 
-    private
-      def get_zone(time_zone)
-        return time_zone if time_zone.nil? || time_zone.is_a?(ActiveSupport::TimeZone)
-        # lookup timezone based on identifier (unless we've been passed a TZInfo::Timezone)
-        unless time_zone.respond_to?(:period_for_local)
-          time_zone = ActiveSupport::TimeZone[time_zone] || TZInfo::Timezone.get(time_zone) rescue nil
-        end
-        # Return if a TimeZone instance, or wrap in a TimeZone instance if a TZInfo::Timezone
-        if time_zone
-          time_zone.is_a?(ActiveSupport::TimeZone) ? time_zone : ActiveSupport::TimeZone.create(time_zone.name, nil, time_zone)
-        end
+    # Returns a TimeZone instance or nil, or raises an ArgumentError for invalid timezones.
+    def find_zone!(time_zone)
+      return time_zone if time_zone.nil? || time_zone.is_a?(ActiveSupport::TimeZone)
+      # lookup timezone based on identifier (unless we've been passed a TZInfo::Timezone)
+      unless time_zone.respond_to?(:period_for_local)
+        time_zone = ActiveSupport::TimeZone[time_zone] || TZInfo::Timezone.get(time_zone)
       end
+      # Return if a TimeZone instance, or wrap in a TimeZone instance if a TZInfo::Timezone
+      time_zone.is_a?(ActiveSupport::TimeZone) ? time_zone : ActiveSupport::TimeZone.create(time_zone.name, nil, time_zone)
+    rescue TZInfo::InvalidTimezoneIdentifier
+      raise ArgumentError, "Invalid Timezone: #{time_zone}"
+    end
+
+    def find_zone(time_zone)
+      find_zone!(time_zone) rescue nil
+    end
   end
 
   # Returns the simultaneous time in <tt>Time.zone</tt>.
@@ -74,6 +81,6 @@ class Time
   def in_time_zone(zone = ::Time.zone)
     return self unless zone
 
-    ActiveSupport::TimeWithZone.new(utc? ? self : getutc, ::Time.__send__(:get_zone, zone))
+    ActiveSupport::TimeWithZone.new(utc? ? self : getutc, ::Time.find_zone!(zone))
   end
 end