From fc242945bae5c63cd512ff579d6bef81824858f2 Mon Sep 17 00:00:00 2001
From: Koichi ITO <koic.ito@gmail.com>
Date: Thu, 16 Apr 2020 01:41:51 +0900
Subject: [PATCH] Fix a false positive for
 `Layout/SpaceAroundMethodCallOperator`

This PR fixes the following false positive for
`Layout/SpaceAroundMethodCallOperator` cop when there is
a space between `.` operator and a comment.

```ruby
foo. # comment
  bar.baz
```

```console
% rubocop --only Layout/SpaceAroundMethodCallOperator
(snip)

Inspecting 1 file
C

Offenses:

example.rb:1:5: C: Layout/SpaceAroundMethodCallOperator: Avoid using
spaces around a method call operator.
foo. # comment
    ^

1 file inspected, 1 offense detected
```

Also this PR does not add to the changelog entry because
`Layout/SpaceAroundMethodCallOperator` cop has not been released yet.
---
 .../space_around_method_call_operator.rb      |  6 +++--
 .../space_around_method_call_operator_spec.rb | 22 +++++++++++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/lib/rubocop/cop/layout/space_around_method_call_operator.rb b/lib/rubocop/cop/layout/space_around_method_call_operator.rb
index 78b9b473fac..160e28b1d3e 100644
--- a/lib/rubocop/cop/layout/space_around_method_call_operator.rb
+++ b/lib/rubocop/cop/layout/space_around_method_call_operator.rb
@@ -72,7 +72,7 @@ def check_and_add_offense(node, add_left_offense = true)
           left = previous_token(operator)
           right = next_token(operator)
 
-          if valid_right_token?(right, operator)
+          if !right.comment? && valid_right_token?(right, operator)
             no_space_offenses(node, operator, right, MSG)
           end
           return unless valid_left_token?(left, operator)
@@ -121,7 +121,9 @@ def left_token_for_auto_correction(node, operator)
 
         def right_token_for_auto_correction(operator)
           right_token = next_token(operator)
-          return right_token if valid_right_token?(right_token, operator)
+          if !right_token.comment? && valid_right_token?(right_token, operator)
+            return right_token
+          end
 
           operator
         end
diff --git a/spec/rubocop/cop/layout/space_around_method_call_operator_spec.rb b/spec/rubocop/cop/layout/space_around_method_call_operator_spec.rb
index 970cc6b6961..e4e9e97880a 100644
--- a/spec/rubocop/cop/layout/space_around_method_call_operator_spec.rb
+++ b/spec/rubocop/cop/layout/space_around_method_call_operator_spec.rb
@@ -177,6 +177,28 @@
         foo.bar.buzz
       RUBY
     end
+
+    context 'when there is a space between `.` operator and a comment' do
+      it 'does not register an offense when there is not a space before `.`' do
+        expect_no_offenses(<<~RUBY)
+          foo. # comment
+            bar.baz
+        RUBY
+      end
+
+      it 'registers an offense when there is a space before `.`' do
+        expect_offense(<<~RUBY)
+          foo . # comment
+             ^ Avoid using spaces around a method call operator.
+            bar.baz
+        RUBY
+
+        expect_correction(<<~RUBY)
+          foo. # comment
+            bar.baz
+        RUBY
+      end
+    end
   end
 
   context 'safe navigation operator' do