Improving auto correction's API

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## master (unreleased)
 
+### New features
+
+* [#7868](https://github.com/rubocop-hq/rubocop/pull/7868): `Cop::Base` is the new recommended base class for cops. Extensive refactoring of `Team`, `Commissioner`. ([@marcandre][])
+
 ## 0.86.0 (2020-06-22)
 
 ### New features

docs/modules/ROOT/nav.adoc

@@ -18,6 +18,7 @@
 ** xref:cops_naming.adoc[Naming]
 ** xref:cops_security.adoc[Security]
 ** xref:cops_style.adoc[Style]
+** xref:v1_upgrade_notes.adoc[Style]
 * xref:extensions.adoc[Extensions]
 * xref:integration_with_other_tools.adoc[Integration with Other Tools]
 * xref:automated_code_review.adoc[Automated Code Review]

docs/modules/ROOT/pages/cops_lint.adoc

@@ -3274,8 +3274,7 @@ end
 | -
 |===
 
-This is not actually a cop. It does not inspect anything. It just
-provides methods to repack Parser's diagnostics/errors
+This cop repacks Parser's diagnostics/errors
 into RuboCop's offenses.
 
 == Lint/ToJSON

docs/modules/ROOT/pages/development.adoc

@@ -186,10 +186,13 @@ the expression achieved previously:
 [source,ruby]
 ----
 def_node_matcher :not_empty_call?, <<~PATTERN
-  (send (send (...) :empty?) :!)
+  (send (send $(...) :empty?) :!)
 PATTERN
 ----
 
+Note that we added a `$` sign to capture the "expression" in `!<expression>.empty?`,
+it will become useful later.
+
 Get yourself familiar with the AST node hooks that
 https://www.rubydoc.info/gems/parser/Parser/AST/Processor[`parser`]
 and https://www.rubydoc.info/gems/rubocop-ast/RuboCop/AST/Traversal[`rubocop-ast`]
@@ -222,11 +225,11 @@ module RuboCop
       #
       #   # good
       #   array.any?
-      class SimplifyNotEmptyWithAny < Cop
+      class SimplifyNotEmptyWithAny < Base
         MSG = 'Use `.any?` and remove the negation part.'.freeze
 
         def_node_matcher :not_empty_call?, <<~PATTERN
-          (send (send (...) :empty?) :!)
+          (send (send $(...) :empty?) :!)
         PATTERN
 
         def on_send(node)
@@ -244,10 +247,7 @@ Update the spec to cover the expected syntax:
 
 [source,ruby]
 ----
-describe RuboCop::Cop::Style::SimplifyNotEmptyWithAny do
-  let(:config) { RuboCop::Config.new }
-  subject(:cop) { described_class.new(config) }
-
+describe RuboCop::Cop::Style::SimplifyNotEmptyWithAny, :config do
   it 'registers an offense when using `!a.empty?`' do
     expect_offense(<<~RUBY)
       !array.empty?
@@ -267,33 +267,45 @@ end
 === Auto-correct
 
 The auto-correct can help humans automatically fix offenses that have been detected.
-It's necessary to define an `autocorrect` method that returns a lambda
-https://github.com/whitequark/parser/blob/master/lib/parser/rewriter.rb[rewriter]
-with the corrector where you can give instructions about what to do with the
+It's necessary to `extend AutoCorrector`.
+The method `add_offense` yields a corrector object that is a thin wrapper on
+https://www.rubydoc.info/gems/parser/Parser/Source/TreeRewriter[parser's TreeRewriter]
+to which you can give instructions about what to do with the
 offensive node.
 
 Let's start with a simple spec to cover it:
 
 [source,ruby]
 ----
-it 'autocorrect `!a.empty?` to `a.any?` ' do
-  expect(autocorrect_source('!a.empty?')).to eq('a.any?')
+it 'corrects `!a.empty?`' do
+  expect_offense(<<~RUBY)
+    !array.empty?
+    ^^^^^^^^^^^^^ Use `.any?` and remove the negation part.
+  RUBY
+
+  expect_correction(<<~RUBY)
+    array.any?
+  RUBY
 end
 ----
 
-And then define the `autocorrect` method on the cop side:
+And then add the autocorrecting block on the cop side:
 
 [source,ruby]
 ----
-def autocorrect(node)
-  lambda do |corrector|
-    internal_expression = node.children[0].children[0].source
-    corrector.replace(node, "#{internal_expression}.any?")
+extend AutoCorrector
+
+def on_send(node)
+  expression = not_empty_call?(node)
+  return unless expression
+
+  add_offense(node) do |corrector|
+    corrector.replace(node, "#{expression.source}.any?")
   end
 end
 ----
 
-The corrector allows you to `insert_after` and `insert_before` or
+The corrector allows you to `insert_after`, `insert_before`, `wrap` or
 `replace` a specific node or in any specific range of the code.
 
 Range can be determined on `node.location` where it brings specific
@@ -319,12 +331,13 @@ And then on the autocorrect method, you just need to use the `cop_config` it:
 
 [source,ruby]
 ----
-def autocorrect(node)
-  lambda do |corrector|
-    internal_expression = node.children[0].children[0].source
-    replacement = cop_config['ReplaceAnyWith'] || "any?"
-    new_expression = "#{internal_expression}.#{replacement}"
-    corrector.replace(node, new_expression)
+def on_send(node)
+  expression = not_empty_call?(node)
+  return unless expression
+
+  add_offense(node) do |corrector|
+    replacement = cop_config['ReplaceAnyWith'] || 'any?'
+    corrector.replace(node, "#{expression.source}.#{replacement}")
   end
 end
 ----