rubocops/no_fileutils_rmrf: Fix rmtree on a method returning Pathname

- Tidy up the node matchers. Either `FileUtils.rm_rf` or `rm_rf` on a
  `Pathname` instance or `self`.

Library/Homebrew/rubocops/no_fileutils_rmrf.rb

@@ -11,35 +11,38 @@ class NoFileutilsRmrf < Base
 
  MSG = "Use `rm` or `rm_r` instead of `rm_rf`, `rm_f`, or `rmtree`."
 
- def_node_matcher :fileutils_rm_r_f_tree?, <<~PATTERN
- (send (const {nil? cbase} :FileUtils) {:rm_rf :rm_f :rmtree} ...)
+ def_node_matcher :any_receiver_rm_r_f?, <<~PATTERN
+ (send
+ {(const {nil? cbase} :FileUtils) (self)}
+ {:rm_rf :rm_f}
+ ...)
  PATTERN
 
- def_node_matcher :instance_rmtree?, <<~PATTERN
- (send (lvar ...) :rmtree ...)
+ def_node_matcher :no_receiver_rm_r_f?, <<~PATTERN
+ (send nil? {:rm_rf :rm_f} ...)
  PATTERN
 
- def_node_matcher :self_rm_r_f_tree?, <<~PATTERN
- (send (self) {:rm_rf :rm_f :rmtree} ...)
+ def_node_matcher :no_receiver_rmtree?, <<~PATTERN
+ (send nil? :rmtree ...)
  PATTERN
 
- def_node_matcher :plain_rm_r_f_tree?, <<~PATTERN
- (send nil? {:rm_rf :rm_f :rmtree} ...)
+ def_node_matcher :any_receiver_rmtree?, <<~PATTERN
+ (send !nil? :rmtree ...)
  PATTERN
 
  def on_send(node)
  return if neither_rm_rf_nor_rmtree?(node)
 
  add_offense(node) do |corrector|
- class_name = "FileUtils." if fileutils_rm_r_f_tree?(node) || instance_rmtree?(node)
+ class_name = "FileUtils." if any_receiver_rm_r_f?(node) || any_receiver_rmtree?(node)
  new_method = if node.method?(:rm_rf) || node.method?(:rmtree)
  "rm_r"
  else
  "rm"
  end
 
- args = if instance_rmtree?(node)
- node.receiver.source
+ args = if any_receiver_rmtree?(node)
+ node.receiver&.source || node.arguments.first&.source
  else
  node.arguments.first.source
  end
@@ -49,8 +52,8 @@ def on_send(node)
  end
 
  def neither_rm_rf_nor_rmtree?(node)
- !self_rm_r_f_tree?(node) && !plain_rm_r_f_tree?(node) &&
- !fileutils_rm_r_f_tree?(node) && !instance_rmtree?(node)
+ !any_receiver_rm_r_f?(node) && !no_receiver_rm_r_f?(node) &&
+ !any_receiver_rmtree?(node) && !no_receiver_rmtree?(node)
  end
  end
  end

Library/Homebrew/test/rubocops/no_fileutils_rmrf_spec.rb

@@ -59,6 +59,11 @@
  other_dir = Pathname("path/to/other/directory")
  other_dir.rmtree
  ^^^^^^^^^^^^^^^^ Homebrew/NoFileutilsRmrf: #{RuboCop::Cop::Homebrew::NoFileutilsRmrf::MSG}
+ def buildpath
+ Pathname("path/to/yet/another/directory")
+ end
+ buildpath.rmtree
+ ^^^^^^^^^^^^^^^^ Homebrew/NoFileutilsRmrf: #{RuboCop::Cop::Homebrew::NoFileutilsRmrf::MSG}
  RUBY
  end
 
@@ -67,12 +72,20 @@
  rmtree("path/to/directory")
  other_dir = Pathname("path/to/other/directory")
  other_dir.rmtree
+ def buildpath
+ Pathname("path/to/yet/another/directory")
+ end
+ buildpath.rmtree
  RUBY
 
  expect(corrected).to eq(<<~RUBY)
  rm_r("path/to/directory")
  other_dir = Pathname("path/to/other/directory")
  FileUtils.rm_r(other_dir)
+ def buildpath
+ Pathname("path/to/yet/another/directory")
+ end
+ FileUtils.rm_r(buildpath)
  RUBY
  end
  end