[Fix #6699] Fix a false negative for Layout/IndentationWidth

[koic]

Fixes #6699.

This PR fixes infinite loop for Layout/IndentationWidth and Layout/IndentationConsistency when bad modifier indentation before good method definition.

# exmaple.rb
class Foo
      private

  def foo
  end
end

First, auto-corrected by Layout/IndentationConsistency.

% rubocop -v
0.65.0
% rubocop -a --only Layout/IndentationConsistency example.rb
Inspecting 1 file
C

Offenses:

example.rb:4:3: C: [Corrected] Layout/IndentationConsistency: Inconsistent indentation detected.
  def foo ...
  ^^^^^^^

1 file inspected, 1 offense detected, 1 offense corrected

% g diff
diff --git a/example.rb b/example.rb
index 23d3556..974f101 100644
--- a/example.rb
+++ b/example.rb
@@ -1,6 +1,6 @@
 class Foo
       private

-  def foo
-  end
+      def foo
+      end
 end

Next, auto-corrected by Layout/IndentationWidth.

% rubocop -a --only Layout/IndentationWidth example.rb
Inspecting 1 file
C

Offenses:

example.rb:4:1: C: [Corrected] Layout/IndentationWidth: Use 2 (not 6)
spaces for indentation.
      def foo
^^^^^^

1 file inspected, 1 offense detected, 1 offense corrected

This will return to the original code.

% g diff
diff --git a/example.rb b/example.rb
index 974f101..23d3556 100644
--- a/example.rb
+++ b/example.rb
@@ -1,6 +1,6 @@
 class Foo
       private

-      def foo
-      end
+  def foo
+  end
 end

That caused the infinite loop in Layout/IndentationConsistency and Layout/IndentationWidth.

With this PR, Layout/indentationWidth cop makes aware of the bad modifier indentation before good method definition.

% rubocop -a --only Layout/IndentationWidth example.rb
Inspecting 1 file
C

Offenses:

example.rb:2:1: C: [Corrected] Layout/IndentationWidth: Use 2 (not 6)
spaces for indentation.
      private
^^^^^^

1 file inspected, 1 offense detected, 1 offense corrected

diff --git a/example.rb b/example.rb
index 23d3556..07525ec 100644
--- a/example.rb
+++ b/example.rb
@@ -1,5 +1,5 @@
 class Foo
-      private
+  private

   def foo
   end

This PR fixes the above false negative. That would be an auto-correct expected.

---

Before submitting the PR make sure the following are checked:

• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Added an entry to the Changelog if the new code introduces user-observable changes. See changelog entry format.
• The PR relates to only one subject with a clear title
  and description in grammatically correct, complete sentences.
• Run bundle exec rake default. It executes all tests and RuboCop for itself, and generates the documentation.

[koic]

📝I extracted to the method because it was warned by Metrics/AbcSize cop.

[Drenmi]

What are some cases where the first child would not be nil or Node? If there are such cases, we should add unit tests. If we can't think of any, this might be a bit defensive. 🙂

[koic]

I updated to the following fine approach.
#6792 (comment)

[Drenmi]

Perhaps we can use a node pattern to clean this up, e.g.:

def_node_matcher :access_modifier?, <<-PATTERN
  [(send ...) access_modifier?]
PATTERN

def select_check_member(member)
  return unless member

  if access_modifier?(member.children.first)
    member.children.first
  else
    member
  end
end

[koic]

Oh, I could not think of this method. Thank you for telling me a fine approach!

[Drenmi]

🚀