Enhance Rails/TimeZone to accept methods with the :in timezone option

Author: fatkodima

changelog/fix_time_zone_to_accept_in_option.md

@@ -0,0 +1 @@
+* [#821](https://github.com/rubocop/rubocop-rails/issues/821): Enhance `Rails/TimeZone` to accept methods with the `:in` timezone option. ([@fatkodima][])

lib/rubocop/cop/rails/time_zone.rb

@@ -228,12 +228,25 @@ def acceptable_methods(klass, method_name, node)
           acceptable
         end
 
-        # Time.new can be called with a time zone offset
+        # Time.new, Time.at, and Time.now can be called with a time zone offset
         # When it is, that should be considered safe
         # Example:
         # Time.new(1988, 3, 15, 3, 0, 0, "-05:00")
         def offset_provided?(node)
-          node.arguments.size >= 7
+          case node.method_name
+          when :new
+            node.arguments.size == 7 || offset_option_provided?(node)
+          when :at, :now
+            offset_option_provided?(node)
+          end
+        end
+
+        def offset_option_provided?(node)
+          options = node.last_argument
+          options&.hash_type? &&
+            options.each_pair.any? do |pair|
+              pair.key.sym_type? && pair.key.value == :in && !pair.value.nil_type?
+            end
         end
       end
     end

spec/rubocop/cop/rails/time_zone_spec.rb

@@ -11,6 +11,19 @@
       RUBY
     end
 
+    it 'registers an offense for Time.now with nil :in option' do
+      expect_offense(<<~RUBY)
+        Time.now(in: nil)
+             ^^^ Do not use `Time.now` without zone. Use `Time.zone.now` instead.
+      RUBY
+    end
+
+    it 'does not register an offense for Time.now with :in option' do
+      expect_no_offenses(<<~RUBY)
+        Time.now(in: '+03:00')
+      RUBY
+    end
+
     it 'registers an offense for Time.new without argument' do
       expect_offense(<<~RUBY)
         Time.new
@@ -45,6 +58,19 @@
       RUBY
     end
 
+    it 'registers an offense for Time.new with nil :in option' do
+      expect_offense(<<~RUBY)
+        Time.new(2012, 6, 10, 12, 00, in: nil)
+             ^^^ Do not use `Time.new` without zone. Use `Time.zone.local` instead.
+      RUBY
+    end
+
+    it 'does not register an offense for Time.new with :in option' do
+      expect_no_offenses(<<~RUBY)
+        Time.new(2012, 6, 10, 12, 00, in: '-05:00')
+      RUBY
+    end
+
     it 'registers an offense for ::Time.now' do
       expect_offense(<<~RUBY)
         ::Time.now
@@ -149,6 +175,19 @@
       RUBY
     end
 
+    it 'registers an offense for Time.at with nil :in option' do
+      expect_offense(<<~RUBY)
+        Time.at(ts, in: nil)
+             ^^ Do not use `Time.at` without zone. Use `Time.zone.at` instead.
+      RUBY
+    end
+
+    it 'does not register an offense for Time.at with :in option' do
+      expect_no_offenses(<<~RUBY)
+        Time.at(ts, in: '+03:00')
+      RUBY
+    end
+
     it 'registers an offense for Time.parse.localtime(offset)' do
       expect_offense(<<~RUBY)
         Time.parse('12:00').localtime('+03:00')