From 74dde0e64da36188aebaf961df8f6c91ee9436f4 Mon Sep 17 00:00:00 2001
From: Robert Fletcher <lobatifricha@gmail.com>
Date: Sun, 19 Jan 2020 16:41:38 -0800
Subject: [PATCH 1/9] Add NoLet cop

Fixes #862
---
 CHANGELOG.md                                  |   2 +
 config/default.yml                            |   7 +
 .../memoized_helpers_in_example_group.rb      | 136 ++++++++++++++++++
 lib/rubocop/cop/rspec_cops.rb                 |   1 +
 manual/cops.md                                |   1 +
 manual/cops_rspec.md                          | 116 +++++++++++++++
 .../memoized_helpers_in_example_group_spec.rb | 127 ++++++++++++++++
 7 files changed, 390 insertions(+)
 create mode 100644 lib/rubocop/cop/rspec/memoized_helpers_in_example_group.rb
 create mode 100644 spec/rubocop/cop/rspec/memoized_helpers_in_example_group_spec.rb

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 36833bd22..763896658 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -55,6 +55,7 @@
 * Add `RSpec/RepeatedExampleGroupDescription` cop. ([@lazycoder9][])
 * Add block name and other lines to `RSpec/ScatteredSetup` message. ([@elebow][])
 * Fix `RSpec/RepeatedDescription` to take into account example metadata. ([@lazycoder9][])
+* Add `RSpec/MemoizedHelpersInExampleGroup` cop. ([@mockdeep][])
 
 ## 1.37.1 (2019-12-16)
 
@@ -542,3 +543,4 @@ Compatibility release so users can upgrade RuboCop to 0.51.0. No new features.
 [@elliterate]: https://github.com/elliterate
 [@mlarraz]: https://github.com/mlarraz
 [@jtannas]: https://github.com/jtannas
+[@mockdeep]: https://github.com/mockdeep
diff --git a/config/default.yml b/config/default.yml
index c59d31955..803d8f8d9 100644
--- a/config/default.yml
+++ b/config/default.yml
@@ -347,6 +347,13 @@ RSpec/LetSetup:
   VersionAdded: '1.7'
   StyleGuide: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/LetSetup
 
+RSpec/MemoizedHelpersInExampleGroup:
+  Description: Checks if example groups contain too many `let` and `subject` calls.
+  Enabled: false
+  AllowSubject: false
+  Max: 5
+  StyleGuide: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MemoizedHelpersInExampleGroup
+
 RSpec/MessageChain:
   Description: Check that chains of messages are not being stubbed.
   Enabled: true
diff --git a/lib/rubocop/cop/rspec/memoized_helpers_in_example_group.rb b/lib/rubocop/cop/rspec/memoized_helpers_in_example_group.rb
new file mode 100644
index 000000000..e18b36cf4
--- /dev/null
+++ b/lib/rubocop/cop/rspec/memoized_helpers_in_example_group.rb
@@ -0,0 +1,136 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module RSpec
+      # Checks if example groups contain too many `let` and `subject` calls.
+      #
+      # This cop is configurable using the `Max` option and the `AllowSubject`
+      # which will configure the cop to only register offenses on calls to
+      # `let` and not calls to `subject`.
+      #
+      # @example
+      #   # bad
+      #   describe MyClass do
+      #     let(:foo) { [] }
+      #     let(:bar) { [] }
+      #     let!(:booger) { [] }
+      #     subject { {} }
+      #     subject(:wat) { {} }
+      #     subject!(:boo) { {} }
+      #   end
+      #
+      #   describe MyClass do
+      #     let(:foo) { [] }
+      #     let(:bar) { [] }
+      #
+      #     context 'when stuff' do
+      #       let!(:booger) { [] }
+      #       subject { {} }
+      #       subject(:wat) { {} }
+      #       subject!(:boo) { {} }
+      #     end
+      #   end
+      #
+      #   # good
+      #   describe MyClass do
+      #     let(:foo) { [] }
+      #     let!(:booger) { [] }
+      #     subject { {} }
+      #     subject(:wat) { {} }
+      #     subject!(:boo) { {} }
+      #   end
+      #
+      #   describe MyClass do
+      #     context 'when stuff' do
+      #       let(:foo) { [] }
+      #       let(:bar) { [] }
+      #       let!(:booger) { [] }
+      #     end
+      #
+      #     context 'when other stuff' do
+      #       subject { {} }
+      #       subject(:wat) { {} }
+      #       subject!(:boo) { {} }
+      #     end
+      #   end
+      #
+      # @example with AllowSubject configuration
+      #
+      #   # rubocop.yml
+      #   # RSpec/MemoizedHelpersInExampleGroup:
+      #   #   AllowSubject: true
+      #
+      #   # bad
+      #   describe MyClass do
+      #     let(:foo) { [] }
+      #     let(:bar) { [] }
+      #     let!(:booger) { [] }
+      #     let(:subject) { {} }
+      #     let(:wat) { {} }
+      #     let!(:boo) { {} }
+      #   end
+      #
+      #   # good
+      #   describe MyClass do
+      #     let(:foo) { [] }
+      #     let(:bar) { [] }
+      #     let!(:booger) { [] }
+      #     subject { {} }
+      #     subject(:wat) { {} }
+      #     subject!(:boo) { {} }
+      #   end
+      #
+      # @example with Max configuration
+      #
+      #   # rubocop.yml
+      #   # RSpec/MemoizedHelpersInExampleGroup:
+      #   #   Max: 0
+      #
+      #   # bad
+      #   describe MyClass do
+      #     let(:foo) { [] }
+      #   end
+      #
+      #   # good
+      #   describe MyClass do
+      #     def foo; []; end
+      #   end
+      #
+      class MemoizedHelpersInExampleGroup < Cop
+        MSG = 'Example has too many memoized helpers [%<count>d/%<max>d]'
+
+        def on_block(node)
+          return unless spec_group?(node)
+
+          count = count_helpers(node)
+
+          node.each_ancestor(:block) do |ancestor|
+            count += count_helpers(ancestor)
+          end
+
+          return if count <= max
+
+          add_offense(node, message: format(MSG, count: count, max: max))
+        end
+
+        private
+
+        def count_helpers(node)
+          example_group = RuboCop::RSpec::ExampleGroup.new(node)
+          count = example_group.lets.count
+          count += example_group.subjects.count unless allow_subject?
+          count
+        end
+
+        def max
+          cop_config['Max']
+        end
+
+        def allow_subject?
+          cop_config['AllowSubject']
+        end
+      end
+    end
+  end
+end
diff --git a/lib/rubocop/cop/rspec_cops.rb b/lib/rubocop/cop/rspec_cops.rb
index 4fe56e997..5ecabb42b 100644
--- a/lib/rubocop/cop/rspec_cops.rb
+++ b/lib/rubocop/cop/rspec_cops.rb
@@ -59,6 +59,7 @@
 require_relative 'rspec/leaky_constant_declaration'
 require_relative 'rspec/let_before_examples'
 require_relative 'rspec/let_setup'
+require_relative 'rspec/memoized_helpers_in_example_group'
 require_relative 'rspec/message_chain'
 require_relative 'rspec/message_expectation'
 require_relative 'rspec/message_spies'
diff --git a/manual/cops.md b/manual/cops.md
index 1e191ee0e..5f57c2636 100644
--- a/manual/cops.md
+++ b/manual/cops.md
@@ -58,6 +58,7 @@
 * [RSpec/LeakyConstantDeclaration](cops_rspec.md#rspecleakyconstantdeclaration)
 * [RSpec/LetBeforeExamples](cops_rspec.md#rspecletbeforeexamples)
 * [RSpec/LetSetup](cops_rspec.md#rspecletsetup)
+* [RSpec/MemoizedHelpersInExampleGroup](cops_rspec.md#rspecmemoizedhelpersinexamplegroup)
 * [RSpec/MessageChain](cops_rspec.md#rspecmessagechain)
 * [RSpec/MessageExpectation](cops_rspec.md#rspecmessageexpectation)
 * [RSpec/MessageSpies](cops_rspec.md#rspecmessagespies)
diff --git a/manual/cops_rspec.md b/manual/cops_rspec.md
index 5ca0c1e12..22163d99f 100644
--- a/manual/cops_rspec.md
+++ b/manual/cops_rspec.md
@@ -1890,6 +1890,122 @@ end
 
 * [https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/LetSetup](https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/LetSetup)
 
+## RSpec/MemoizedHelpersInExampleGroup
+
+Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged
+--- | --- | --- | --- | ---
+Disabled | Yes | No | - | -
+
+Checks if example groups contain too many `let` and `subject` calls.
+
+This cop is configurable using the `Max` option and the `AllowSubject`
+which will configure the cop to only register offenses on calls to
+`let` and not calls to `subject`.
+
+### Examples
+
+```ruby
+# bad
+describe MyClass do
+  let(:foo) { [] }
+  let(:bar) { [] }
+  let!(:booger) { [] }
+  subject { {} }
+  subject(:wat) { {} }
+  subject!(:boo) { {} }
+end
+
+describe MyClass do
+  let(:foo) { [] }
+  let(:bar) { [] }
+
+  context 'when stuff' do
+    let!(:booger) { [] }
+    subject { {} }
+    subject(:wat) { {} }
+    subject!(:boo) { {} }
+  end
+end
+
+# good
+describe MyClass do
+  let(:foo) { [] }
+  let!(:booger) { [] }
+  subject { {} }
+  subject(:wat) { {} }
+  subject!(:boo) { {} }
+end
+
+describe MyClass do
+  context 'when stuff' do
+    let(:foo) { [] }
+    let(:bar) { [] }
+    let!(:booger) { [] }
+  end
+
+  context 'when other stuff' do
+    subject { {} }
+    subject(:wat) { {} }
+    subject!(:boo) { {} }
+  end
+end
+```
+#### with AllowSubject configuration
+
+```ruby
+# rubocop.yml
+# RSpec/MemoizedHelpersInExampleGroup:
+#   AllowSubject: true
+
+# bad
+describe MyClass do
+  let(:foo) { [] }
+  let(:bar) { [] }
+  let!(:booger) { [] }
+  let(:subject) { {} }
+  let(:wat) { {} }
+  let!(:boo) { {} }
+end
+
+# good
+describe MyClass do
+  let(:foo) { [] }
+  let(:bar) { [] }
+  let!(:booger) { [] }
+  subject { {} }
+  subject(:wat) { {} }
+  subject!(:boo) { {} }
+end
+```
+#### with Max configuration
+
+```ruby
+# rubocop.yml
+# RSpec/MemoizedHelpersInExampleGroup:
+#   Max: 0
+
+# bad
+describe MyClass do
+  let(:foo) { [] }
+end
+
+# good
+describe MyClass do
+  def foo; []; end
+end
+```
+
+### Configurable attributes
+
+Name | Default value | Configurable values
+--- | --- | ---
+AllowSubject | `false` | Boolean
+Max | `5` | Integer
+
+### References
+
+* [https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MemoizedHelpersInExampleGroup](https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MemoizedHelpersInExampleGroup)
+
 ## RSpec/MessageChain
 
 Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged
diff --git a/spec/rubocop/cop/rspec/memoized_helpers_in_example_group_spec.rb b/spec/rubocop/cop/rspec/memoized_helpers_in_example_group_spec.rb
new file mode 100644
index 000000000..d71559b1e
--- /dev/null
+++ b/spec/rubocop/cop/rspec/memoized_helpers_in_example_group_spec.rb
@@ -0,0 +1,127 @@
+# frozen_string_literal: true
+
+RSpec.describe RuboCop::Cop::RSpec::MemoizedHelpersInExampleGroup, :config do
+  let(:cop_config) { { 'Max' => 1 } }
+
+  it 'flags an offense when using more than max `#let` calls' do
+    expect_offense(<<~RUBY)
+      describe Foo do
+      ^^^^^^^^^^^^^^^ Example has too many memoized helpers [2/1]
+        let(:foo) { Foo.new }
+        let(:bar) { Bar.new }
+      end
+    RUBY
+  end
+
+  it 'flags an offense when using `#subject` without name' do
+    expect_offense(<<~RUBY)
+      describe Foo do
+      ^^^^^^^^^^^^^^^ Example has too many memoized helpers [2/1]
+        subject { Foo.new }
+        let(:foo) { Foo.new }
+      end
+    RUBY
+  end
+
+  it 'flags an offense when using `#subject` with name' do
+    expect_offense(<<~RUBY)
+      describe Foo do
+      ^^^^^^^^^^^^^^^ Example has too many memoized helpers [2/1]
+        subject(:foo) { Foo.new }
+        let(:foo) { Foo.new }
+      end
+    RUBY
+  end
+
+  it 'flags an offense when using `#let!`' do
+    expect_offense(<<~RUBY)
+      describe Foo do
+      ^^^^^^^^^^^^^^^ Example has too many memoized helpers [2/1]
+        let(:foo) { Foo.new }
+        let!(:foo) { Foo.new }
+      end
+    RUBY
+  end
+
+  it 'flags an offense when using `#subject!`' do
+    expect_offense(<<~RUBY)
+      describe Foo do
+      ^^^^^^^^^^^^^^^ Example has too many memoized helpers [2/1]
+        subject!(:foo) { Foo.new }
+        let(:foo) { Foo.new }
+      end
+    RUBY
+  end
+
+  it 'does not flag an offense when using <= max `#let` calls' do
+    expect_no_offenses(<<~RUBY)
+      describe Foo do
+        let(:foo) { Foo.new }
+      end
+    RUBY
+  end
+
+  it 'flags an offense when too many `#let` calls are nested' do
+    expect_offense(<<~RUBY)
+      describe Foo do
+        let(:foo) { Foo.new }
+
+        context 'when blah' do
+        ^^^^^^^^^^^^^^^^^^^^^^ Example has too many memoized helpers [2/1]
+          let(:bar) { Bar.new }
+        end
+      end
+    RUBY
+  end
+
+  it 'does not flag an offense when `#let` calls are distributed' do
+    expect_no_offenses(<<~RUBY)
+      describe Foo do
+        context 'when bloo' do
+          let(:foo) { Foo.new }
+        end
+
+        context 'when blah' do
+          let(:bar) { Bar.new }
+        end
+      end
+    RUBY
+  end
+
+  it 'does not flag an offense when using `#before`' do
+    expect_no_offenses(<<~RUBY)
+      describe Foo do
+        before { foo }
+      end
+    RUBY
+  end
+
+  context 'when using AllowSubject configuration', :config do
+    let(:cop_config) { { 'Max' => 0, 'AllowSubject' => true } }
+
+    it 'flags an offense when using `#let`' do
+      expect_offense(<<~RUBY)
+        describe Foo do
+        ^^^^^^^^^^^^^^^ Example has too many memoized helpers [1/0]
+          let(:foo) { Foo.new }
+        end
+      RUBY
+    end
+
+    it 'does not flag an offense when using `#subject` without a name' do
+      expect_no_offenses(<<~RUBY)
+        describe Foo do
+          subject { Foo.new }
+        end
+      RUBY
+    end
+
+    it 'does not flag an offense when using `#subject` with a name' do
+      expect_no_offenses(<<~RUBY)
+        describe Foo do
+          subject(:foo) { Foo.new }
+        end
+      RUBY
+    end
+  end
+end

From d761fc30b2c49537d4ac3338a01f2b2f51e80f0f Mon Sep 17 00:00:00 2001
From: Phil Pirozhkov <pirjsuka@gmail.com>
Date: Mon, 3 Aug 2020 03:52:40 +0300
Subject: [PATCH 2/9] Rename the cop

and fix the build
---
 CHANGELOG.md                                  |  2 +-
 config/default.yml                            | 14 ++---
 ..._group.rb => multiple_memoized_helpers.rb} | 60 ++++++++-----------
 lib/rubocop/cop/rspec_cops.rb                 |  2 +-
 ...c.rb => multiple_memoized_helpers_spec.rb} | 16 ++---
 5 files changed, 42 insertions(+), 52 deletions(-)
 rename lib/rubocop/cop/rspec/{memoized_helpers_in_example_group.rb => multiple_memoized_helpers.rb} (67%)
 rename spec/rubocop/cop/rspec/{memoized_helpers_in_example_group_spec.rb => multiple_memoized_helpers_spec.rb} (81%)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 763896658..bb80c9b79 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@
 * Improve `RSpec/NestedGroups`, `RSpec/FilePath`, `RSpec/DescribeMethod`, `RSpec/MultipleDescribes`, `RSpec/DescribeClass`'s top-level example group detection. ([@pirj][])
 * Add detection of `let!` with a block-pass or a string literal to `RSpec/LetSetup`. ([@pirj][])
 * Add `IgnoredPatterns` configuration option to `RSpec/VariableName`. ([@jtannas][])
+* Add `RSpec/MultipleMemoizedHelpers` cop. ([@mockdeep][])
 
 ## 1.42.0 (2020-07-09)
 
@@ -55,7 +56,6 @@
 * Add `RSpec/RepeatedExampleGroupDescription` cop. ([@lazycoder9][])
 * Add block name and other lines to `RSpec/ScatteredSetup` message. ([@elebow][])
 * Fix `RSpec/RepeatedDescription` to take into account example metadata. ([@lazycoder9][])
-* Add `RSpec/MemoizedHelpersInExampleGroup` cop. ([@mockdeep][])
 
 ## 1.37.1 (2019-12-16)
 
diff --git a/config/default.yml b/config/default.yml
index 803d8f8d9..61f67c9b7 100644
--- a/config/default.yml
+++ b/config/default.yml
@@ -347,13 +347,6 @@ RSpec/LetSetup:
   VersionAdded: '1.7'
   StyleGuide: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/LetSetup
 
-RSpec/MemoizedHelpersInExampleGroup:
-  Description: Checks if example groups contain too many `let` and `subject` calls.
-  Enabled: false
-  AllowSubject: false
-  Max: 5
-  StyleGuide: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MemoizedHelpersInExampleGroup
-
 RSpec/MessageChain:
   Description: Check that chains of messages are not being stubbed.
   Enabled: true
@@ -401,6 +394,13 @@ RSpec/MultipleExpectations:
   VersionChanged: '1.21'
   StyleGuide: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MultipleExpectations
 
+RSpec/MultipleMemoizedHelpers:
+  Description: Checks if example groups contain too many `let` and `subject` calls.
+  Enabled: false
+  AllowSubject: false
+  Max: 5
+  StyleGuide: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MultipleMemoizedHelpers
+
 RSpec/MultipleSubjects:
   Description: Checks if an example group defines `subject` multiple times.
   Enabled: true
diff --git a/lib/rubocop/cop/rspec/memoized_helpers_in_example_group.rb b/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
similarity index 67%
rename from lib/rubocop/cop/rspec/memoized_helpers_in_example_group.rb
rename to lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
index e18b36cf4..471710a5e 100644
--- a/lib/rubocop/cop/rspec/memoized_helpers_in_example_group.rb
+++ b/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
@@ -14,31 +14,31 @@ module RSpec
       #   describe MyClass do
       #     let(:foo) { [] }
       #     let(:bar) { [] }
-      #     let!(:booger) { [] }
-      #     subject { {} }
-      #     subject(:wat) { {} }
-      #     subject!(:boo) { {} }
+      #     let!(:baz) { [] }
+      #     let(:qux) { [] }
+      #     let(:quux) { [] }
+      #     subject(:quuz) { {} }
       #   end
       #
       #   describe MyClass do
       #     let(:foo) { [] }
       #     let(:bar) { [] }
+      #     let!(:baz) { [] }
       #
       #     context 'when stuff' do
-      #       let!(:booger) { [] }
-      #       subject { {} }
-      #       subject(:wat) { {} }
-      #       subject!(:boo) { {} }
+      #       let(:qux) { [] }
+      #       let(:quux) { [] }
+      #       subject(:quuz) { {} }
       #     end
       #   end
       #
       #   # good
       #   describe MyClass do
-      #     let(:foo) { [] }
-      #     let!(:booger) { [] }
-      #     subject { {} }
-      #     subject(:wat) { {} }
-      #     subject!(:boo) { {} }
+      #     let(:bar) { [] }
+      #     let!(:baz) { [] }
+      #     let(:qux) { [] }
+      #     let(:quux) { [] }
+      #     subject(:quuz) { {} }
       #   end
       #
       #   describe MyClass do
@@ -49,42 +49,32 @@ module RSpec
       #     end
       #
       #     context 'when other stuff' do
-      #       subject { {} }
-      #       subject(:wat) { {} }
-      #       subject!(:boo) { {} }
+      #       let(:qux) { [] }
+      #       let(:quux) { [] }
+      #       subject(:quuz) { {} }
       #     end
       #   end
       #
-      # @example with AllowSubject configuration
+      # @example when disabling AllowSubject configuration
       #
       #   # rubocop.yml
-      #   # RSpec/MemoizedHelpersInExampleGroup:
+      #   # RSpec/MultipleMemoizedHelpers:
       #   #   AllowSubject: true
       #
-      #   # bad
-      #   describe MyClass do
-      #     let(:foo) { [] }
-      #     let(:bar) { [] }
-      #     let!(:booger) { [] }
-      #     let(:subject) { {} }
-      #     let(:wat) { {} }
-      #     let!(:boo) { {} }
-      #   end
-      #
       #   # good
       #   describe MyClass do
+      #     subject { {} }
       #     let(:foo) { [] }
       #     let(:bar) { [] }
-      #     let!(:booger) { [] }
-      #     subject { {} }
-      #     subject(:wat) { {} }
-      #     subject!(:boo) { {} }
+      #     let!(:baz) { [] }
+      #     let(:qux) { [] }
+      #     let(:quux) { [] }
       #   end
       #
       # @example with Max configuration
       #
       #   # rubocop.yml
-      #   # RSpec/MemoizedHelpersInExampleGroup:
+      #   # RSpec/MultipleMemoizedHelpers:
       #   #   Max: 0
       #
       #   # bad
@@ -97,8 +87,8 @@ module RSpec
       #     def foo; []; end
       #   end
       #
-      class MemoizedHelpersInExampleGroup < Cop
-        MSG = 'Example has too many memoized helpers [%<count>d/%<max>d]'
+      class MultipleMemoizedHelpers < Base
+        MSG = 'Example group has too many memoized helpers [%<count>d/%<max>d]'
 
         def on_block(node)
           return unless spec_group?(node)
diff --git a/lib/rubocop/cop/rspec_cops.rb b/lib/rubocop/cop/rspec_cops.rb
index 5ecabb42b..b835bf3d6 100644
--- a/lib/rubocop/cop/rspec_cops.rb
+++ b/lib/rubocop/cop/rspec_cops.rb
@@ -59,13 +59,13 @@
 require_relative 'rspec/leaky_constant_declaration'
 require_relative 'rspec/let_before_examples'
 require_relative 'rspec/let_setup'
-require_relative 'rspec/memoized_helpers_in_example_group'
 require_relative 'rspec/message_chain'
 require_relative 'rspec/message_expectation'
 require_relative 'rspec/message_spies'
 require_relative 'rspec/missing_example_group_argument'
 require_relative 'rspec/multiple_describes'
 require_relative 'rspec/multiple_expectations'
+require_relative 'rspec/multiple_memoized_helpers'
 require_relative 'rspec/multiple_subjects'
 require_relative 'rspec/named_subject'
 require_relative 'rspec/nested_groups'
diff --git a/spec/rubocop/cop/rspec/memoized_helpers_in_example_group_spec.rb b/spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb
similarity index 81%
rename from spec/rubocop/cop/rspec/memoized_helpers_in_example_group_spec.rb
rename to spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb
index d71559b1e..6e3951a89 100644
--- a/spec/rubocop/cop/rspec/memoized_helpers_in_example_group_spec.rb
+++ b/spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-RSpec.describe RuboCop::Cop::RSpec::MemoizedHelpersInExampleGroup, :config do
+RSpec.describe RuboCop::Cop::RSpec::MultipleMemoizedHelpers, :config do
   let(:cop_config) { { 'Max' => 1 } }
 
   it 'flags an offense when using more than max `#let` calls' do
     expect_offense(<<~RUBY)
       describe Foo do
-      ^^^^^^^^^^^^^^^ Example has too many memoized helpers [2/1]
+      ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
         let(:foo) { Foo.new }
         let(:bar) { Bar.new }
       end
@@ -16,7 +16,7 @@
   it 'flags an offense when using `#subject` without name' do
     expect_offense(<<~RUBY)
       describe Foo do
-      ^^^^^^^^^^^^^^^ Example has too many memoized helpers [2/1]
+      ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
         subject { Foo.new }
         let(:foo) { Foo.new }
       end
@@ -26,7 +26,7 @@
   it 'flags an offense when using `#subject` with name' do
     expect_offense(<<~RUBY)
       describe Foo do
-      ^^^^^^^^^^^^^^^ Example has too many memoized helpers [2/1]
+      ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
         subject(:foo) { Foo.new }
         let(:foo) { Foo.new }
       end
@@ -36,7 +36,7 @@
   it 'flags an offense when using `#let!`' do
     expect_offense(<<~RUBY)
       describe Foo do
-      ^^^^^^^^^^^^^^^ Example has too many memoized helpers [2/1]
+      ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
         let(:foo) { Foo.new }
         let!(:foo) { Foo.new }
       end
@@ -46,7 +46,7 @@
   it 'flags an offense when using `#subject!`' do
     expect_offense(<<~RUBY)
       describe Foo do
-      ^^^^^^^^^^^^^^^ Example has too many memoized helpers [2/1]
+      ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
         subject!(:foo) { Foo.new }
         let(:foo) { Foo.new }
       end
@@ -67,7 +67,7 @@
         let(:foo) { Foo.new }
 
         context 'when blah' do
-        ^^^^^^^^^^^^^^^^^^^^^^ Example has too many memoized helpers [2/1]
+        ^^^^^^^^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
           let(:bar) { Bar.new }
         end
       end
@@ -102,7 +102,7 @@
     it 'flags an offense when using `#let`' do
       expect_offense(<<~RUBY)
         describe Foo do
-        ^^^^^^^^^^^^^^^ Example has too many memoized helpers [1/0]
+        ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [1/0]
           let(:foo) { Foo.new }
         end
       RUBY

From 3732a9c695adba877bf83e6080417aa3a01a05d6 Mon Sep 17 00:00:00 2001
From: Phil Pirozhkov <pirjsuka@gmail.com>
Date: Mon, 3 Aug 2020 03:59:59 +0300
Subject: [PATCH 3/9] Minor restyling

---
 .../cop/rspec/multiple_memoized_helpers.rb    | 21 +++++++++++--------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb b/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
index 471710a5e..9e29430a2 100644
--- a/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
+++ b/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
@@ -93,11 +93,7 @@ class MultipleMemoizedHelpers < Base
         def on_block(node)
           return unless spec_group?(node)
 
-          count = count_helpers(node)
-
-          node.each_ancestor(:block) do |ancestor|
-            count += count_helpers(ancestor)
-          end
+          count = total_helpers(node)
 
           return if count <= max
 
@@ -106,11 +102,18 @@ def on_block(node)
 
         private
 
-        def count_helpers(node)
+        def total_helpers(node)
+          helpers(node) +
+            node.each_ancestor(:block).map(&method(:helpers)).sum
+        end
+
+        def helpers(node)
           example_group = RuboCop::RSpec::ExampleGroup.new(node)
-          count = example_group.lets.count
-          count += example_group.subjects.count unless allow_subject?
-          count
+          if allow_subject?
+            example_group.lets.count
+          else
+            example_group.lets.count + example_group.subjects.count
+          end
         end
 
         def max

From 418c7fcb810e74302476cc7b7885dff82fc8ed57 Mon Sep 17 00:00:00 2001
From: Phil Pirozhkov <pirjsuka@gmail.com>
Date: Mon, 3 Aug 2020 04:26:03 +0300
Subject: [PATCH 4/9] Update the manual

---
 manual/cops.md       |   2 +-
 manual/cops_rspec.md | 222 +++++++++++++++++++++----------------------
 2 files changed, 107 insertions(+), 117 deletions(-)

diff --git a/manual/cops.md b/manual/cops.md
index 5f57c2636..75a49daa3 100644
--- a/manual/cops.md
+++ b/manual/cops.md
@@ -58,13 +58,13 @@
 * [RSpec/LeakyConstantDeclaration](cops_rspec.md#rspecleakyconstantdeclaration)
 * [RSpec/LetBeforeExamples](cops_rspec.md#rspecletbeforeexamples)
 * [RSpec/LetSetup](cops_rspec.md#rspecletsetup)
-* [RSpec/MemoizedHelpersInExampleGroup](cops_rspec.md#rspecmemoizedhelpersinexamplegroup)
 * [RSpec/MessageChain](cops_rspec.md#rspecmessagechain)
 * [RSpec/MessageExpectation](cops_rspec.md#rspecmessageexpectation)
 * [RSpec/MessageSpies](cops_rspec.md#rspecmessagespies)
 * [RSpec/MissingExampleGroupArgument](cops_rspec.md#rspecmissingexamplegroupargument)
 * [RSpec/MultipleDescribes](cops_rspec.md#rspecmultipledescribes)
 * [RSpec/MultipleExpectations](cops_rspec.md#rspecmultipleexpectations)
+* [RSpec/MultipleMemoizedHelpers](cops_rspec.md#rspecmultiplememoizedhelpers)
 * [RSpec/MultipleSubjects](cops_rspec.md#rspecmultiplesubjects)
 * [RSpec/NamedSubject](cops_rspec.md#rspecnamedsubject)
 * [RSpec/NestedGroups](cops_rspec.md#rspecnestedgroups)
diff --git a/manual/cops_rspec.md b/manual/cops_rspec.md
index 22163d99f..358b315d1 100644
--- a/manual/cops_rspec.md
+++ b/manual/cops_rspec.md
@@ -1890,122 +1890,6 @@ end
 
 * [https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/LetSetup](https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/LetSetup)
 
-## RSpec/MemoizedHelpersInExampleGroup
-
-Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged
---- | --- | --- | --- | ---
-Disabled | Yes | No | - | -
-
-Checks if example groups contain too many `let` and `subject` calls.
-
-This cop is configurable using the `Max` option and the `AllowSubject`
-which will configure the cop to only register offenses on calls to
-`let` and not calls to `subject`.
-
-### Examples
-
-```ruby
-# bad
-describe MyClass do
-  let(:foo) { [] }
-  let(:bar) { [] }
-  let!(:booger) { [] }
-  subject { {} }
-  subject(:wat) { {} }
-  subject!(:boo) { {} }
-end
-
-describe MyClass do
-  let(:foo) { [] }
-  let(:bar) { [] }
-
-  context 'when stuff' do
-    let!(:booger) { [] }
-    subject { {} }
-    subject(:wat) { {} }
-    subject!(:boo) { {} }
-  end
-end
-
-# good
-describe MyClass do
-  let(:foo) { [] }
-  let!(:booger) { [] }
-  subject { {} }
-  subject(:wat) { {} }
-  subject!(:boo) { {} }
-end
-
-describe MyClass do
-  context 'when stuff' do
-    let(:foo) { [] }
-    let(:bar) { [] }
-    let!(:booger) { [] }
-  end
-
-  context 'when other stuff' do
-    subject { {} }
-    subject(:wat) { {} }
-    subject!(:boo) { {} }
-  end
-end
-```
-#### with AllowSubject configuration
-
-```ruby
-# rubocop.yml
-# RSpec/MemoizedHelpersInExampleGroup:
-#   AllowSubject: true
-
-# bad
-describe MyClass do
-  let(:foo) { [] }
-  let(:bar) { [] }
-  let!(:booger) { [] }
-  let(:subject) { {} }
-  let(:wat) { {} }
-  let!(:boo) { {} }
-end
-
-# good
-describe MyClass do
-  let(:foo) { [] }
-  let(:bar) { [] }
-  let!(:booger) { [] }
-  subject { {} }
-  subject(:wat) { {} }
-  subject!(:boo) { {} }
-end
-```
-#### with Max configuration
-
-```ruby
-# rubocop.yml
-# RSpec/MemoizedHelpersInExampleGroup:
-#   Max: 0
-
-# bad
-describe MyClass do
-  let(:foo) { [] }
-end
-
-# good
-describe MyClass do
-  def foo; []; end
-end
-```
-
-### Configurable attributes
-
-Name | Default value | Configurable values
---- | --- | ---
-AllowSubject | `false` | Boolean
-Max | `5` | Integer
-
-### References
-
-* [https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MemoizedHelpersInExampleGroup](https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MemoizedHelpersInExampleGroup)
-
 ## RSpec/MessageChain
 
 Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged
@@ -2235,6 +2119,112 @@ Max | `1` | Integer
 
 * [https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MultipleExpectations](https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MultipleExpectations)
 
+## RSpec/MultipleMemoizedHelpers
+
+Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged
+--- | --- | --- | --- | ---
+Disabled | Yes | No | - | -
+
+Checks if example groups contain too many `let` and `subject` calls.
+
+This cop is configurable using the `Max` option and the `AllowSubject`
+which will configure the cop to only register offenses on calls to
+`let` and not calls to `subject`.
+
+### Examples
+
+```ruby
+# bad
+describe MyClass do
+  let(:foo) { [] }
+  let(:bar) { [] }
+  let!(:baz) { [] }
+  let(:qux) { [] }
+  let(:quux) { [] }
+  subject(:quuz) { {} }
+end
+
+describe MyClass do
+  let(:foo) { [] }
+  let(:bar) { [] }
+  let!(:baz) { [] }
+
+  context 'when stuff' do
+    let(:qux) { [] }
+    let(:quux) { [] }
+    subject(:quuz) { {} }
+  end
+end
+
+# good
+describe MyClass do
+  let(:bar) { [] }
+  let!(:baz) { [] }
+  let(:qux) { [] }
+  let(:quux) { [] }
+  subject(:quuz) { {} }
+end
+
+describe MyClass do
+  context 'when stuff' do
+    let(:foo) { [] }
+    let(:bar) { [] }
+    let!(:booger) { [] }
+  end
+
+  context 'when other stuff' do
+    let(:qux) { [] }
+    let(:quux) { [] }
+    subject(:quuz) { {} }
+  end
+end
+```
+#### when disabling AllowSubject configuration
+
+```ruby
+# rubocop.yml
+# RSpec/MultipleMemoizedHelpers:
+#   AllowSubject: true
+
+# good
+describe MyClass do
+  subject { {} }
+  let(:foo) { [] }
+  let(:bar) { [] }
+  let!(:baz) { [] }
+  let(:qux) { [] }
+  let(:quux) { [] }
+end
+```
+#### with Max configuration
+
+```ruby
+# rubocop.yml
+# RSpec/MultipleMemoizedHelpers:
+#   Max: 0
+
+# bad
+describe MyClass do
+  let(:foo) { [] }
+end
+
+# good
+describe MyClass do
+  def foo; []; end
+end
+```
+
+### Configurable attributes
+
+Name | Default value | Configurable values
+--- | --- | ---
+AllowSubject | `false` | Boolean
+Max | `5` | Integer
+
+### References
+
+* [https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MultipleMemoizedHelpers](https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MultipleMemoizedHelpers)
+
 ## RSpec/MultipleSubjects
 
 Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged

From 3fcd0bb76c25d606914b27d8032afdb2ef0dd885 Mon Sep 17 00:00:00 2001
From: Phil Pirozhkov <pirjsuka@gmail.com>
Date: Tue, 4 Aug 2020 22:55:56 +0300
Subject: [PATCH 5/9] Only count unique variable name definitions

---
 .../cop/rspec/multiple_memoized_helpers.rb    | 24 ++++++++-----
 .../rspec/multiple_memoized_helpers_spec.rb   | 34 +++++++++++++++++--
 2 files changed, 46 insertions(+), 12 deletions(-)

diff --git a/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb b/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
index 9e29430a2..47d2b799c 100644
--- a/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
+++ b/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
@@ -88,12 +88,14 @@ module RSpec
       #   end
       #
       class MultipleMemoizedHelpers < Base
+        include RuboCop::RSpec::Variable
+
         MSG = 'Example group has too many memoized helpers [%<count>d/%<max>d]'
 
         def on_block(node)
           return unless spec_group?(node)
 
-          count = total_helpers(node)
+          count = all_helpers(node).uniq.count
 
           return if count <= max
 
@@ -102,18 +104,22 @@ def on_block(node)
 
         private
 
-        def total_helpers(node)
-          helpers(node) +
-            node.each_ancestor(:block).map(&method(:helpers)).sum
+        def all_helpers(node)
+          [
+            *helpers(node),
+            *node.each_ancestor(:block).flat_map(&method(:helpers))
+          ]
         end
 
         def helpers(node)
           example_group = RuboCop::RSpec::ExampleGroup.new(node)
-          if allow_subject?
-            example_group.lets.count
-          else
-            example_group.lets.count + example_group.subjects.count
-          end
+          variables =
+            if allow_subject?
+              example_group.lets
+            else
+              example_group.lets + example_group.subjects
+            end
+          variables.map { |variable| variable_definition?(variable.send_node) }
         end
 
         def max
diff --git a/spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb b/spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb
index 6e3951a89..21b814867 100644
--- a/spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb
+++ b/spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb
@@ -28,7 +28,7 @@
       describe Foo do
       ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
         subject(:foo) { Foo.new }
-        let(:foo) { Foo.new }
+        let(:bar) { Foo.new }
       end
     RUBY
   end
@@ -38,7 +38,7 @@
       describe Foo do
       ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
         let(:foo) { Foo.new }
-        let!(:foo) { Foo.new }
+        let!(:bar) { Foo.new }
       end
     RUBY
   end
@@ -48,7 +48,7 @@
       describe Foo do
       ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
         subject!(:foo) { Foo.new }
-        let(:foo) { Foo.new }
+        let(:bar) { Foo.new }
       end
     RUBY
   end
@@ -61,6 +61,34 @@
     RUBY
   end
 
+  it 'ignores overridden variables' do
+    expect_no_offenses(<<~RUBY)
+      describe Foo do
+        let(:foo) { Foo.new }
+        context do
+          let(:foo) { Foo.new(1) }
+          context do
+            let(:foo) { Foo.new(1, 2) }
+          end
+        end
+      end
+    RUBY
+  end
+
+  it 'ignores overridden nameless subjects' do
+    expect_no_offenses(<<~RUBY)
+      describe Foo do
+        subject { Foo.new }
+        context do
+          subject { Foo.new(1) }
+          context do
+            subject { Foo.new(1, 2) }
+          end
+        end
+      end
+    RUBY
+  end
+
   it 'flags an offense when too many `#let` calls are nested' do
     expect_offense(<<~RUBY)
       describe Foo do

From c3ab68f0a0a398bf008c18d7bcd5a4035d1b752e Mon Sep 17 00:00:00 2001
From: Phil Pirozhkov <pirjsuka@gmail.com>
Date: Wed, 5 Aug 2020 01:37:31 +0300
Subject: [PATCH 6/9] Allow for --auto-gen-config

---
 lib/rubocop/cop/rspec/multiple_memoized_helpers.rb  |  2 ++
 .../cop/rspec/multiple_memoized_helpers_spec.rb     | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb b/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
index 47d2b799c..d91b00e03 100644
--- a/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
+++ b/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
@@ -88,6 +88,7 @@ module RSpec
       #   end
       #
       class MultipleMemoizedHelpers < Base
+        include ConfigurableMax
         include RuboCop::RSpec::Variable
 
         MSG = 'Example group has too many memoized helpers [%<count>d/%<max>d]'
@@ -99,6 +100,7 @@ def on_block(node)
 
           return if count <= max
 
+          self.max = count
           add_offense(node, message: format(MSG, count: count, max: max))
         end
 
diff --git a/spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb b/spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb
index 21b814867..24b5424e6 100644
--- a/spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb
+++ b/spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb
@@ -152,4 +152,17 @@
       RUBY
     end
   end
+
+  it 'support --auto-gen-config' do
+    inspect_source(<<-RUBY, 'spec/foo_spec.rb')
+      describe Foo do
+        let(:foo) { Foo.new }
+        let(:bar) { Bar.new }
+        let(:baz) { Baz.new }
+        let(:qux) { Qux.new }
+      end
+    RUBY
+
+    expect(cop.config_to_allow_offenses[:exclude_limit]).to eq('Max' => 4)
+  end
 end

From 8d7b3c9713f44687e41104e0650770522f8d02d6 Mon Sep 17 00:00:00 2001
From: Phil Pirozhkov <pirjsuka@gmail.com>
Date: Fri, 7 Aug 2020 02:16:20 +0300
Subject: [PATCH 7/9] Add block-pass support to MultipleMemoizedHelpers

---
 .../cop/rspec/multiple_memoized_helpers.rb    | 22 +++++++++++++------
 lib/rubocop/rspec/variable.rb                 |  2 +-
 spec/smoke_tests/weird_rspec_spec.rb          |  3 +++
 3 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb b/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
index d91b00e03..93b614c02 100644
--- a/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
+++ b/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
@@ -114,14 +114,22 @@ def all_helpers(node)
         end
 
         def helpers(node)
-          example_group = RuboCop::RSpec::ExampleGroup.new(node)
-          variables =
-            if allow_subject?
-              example_group.lets
-            else
-              example_group.lets + example_group.subjects
+          variable_nodes(node).map do |variable_node|
+            if variable_node.block_type?
+              variable_definition?(variable_node.send_node)
+            else # block-pass (`let(:foo, &bar)`)
+              variable_definition?(variable_node)
             end
-          variables.map { |variable| variable_definition?(variable.send_node) }
+          end
+        end
+
+        def variable_nodes(node)
+          example_group = RuboCop::RSpec::ExampleGroup.new(node)
+          if allow_subject?
+            example_group.lets
+          else
+            example_group.lets + example_group.subjects
+          end
         end
 
         def max
diff --git a/lib/rubocop/rspec/variable.rb b/lib/rubocop/rspec/variable.rb
index 2dfe92c0c..887f20ca7 100644
--- a/lib/rubocop/rspec/variable.rb
+++ b/lib/rubocop/rspec/variable.rb
@@ -8,7 +8,7 @@ module Variable
       extend RuboCop::NodePattern::Macros
 
       def_node_matcher :variable_definition?, <<~PATTERN
-        (send #rspec? #{(Helpers::ALL + Subject::ALL).node_pattern_union}
+        (send nil? #{(Helpers::ALL + Subject::ALL).node_pattern_union}
           $({sym str dsym dstr} ...) ...)
       PATTERN
     end
diff --git a/spec/smoke_tests/weird_rspec_spec.rb b/spec/smoke_tests/weird_rspec_spec.rb
index df876e6c6..4d3d29dc6 100644
--- a/spec/smoke_tests/weird_rspec_spec.rb
+++ b/spec/smoke_tests/weird_rspec_spec.rb
@@ -11,6 +11,9 @@
   let (:foo) { 1 }
   let!   (:bar){}
 
+  bar = -> {}
+  let(:foo, &bar)
+
   let :a do end
 
   let(:bar) { <<-HEREDOC }

From edb87e8b0b667d8be9c759ffe6a21d62e08189da Mon Sep 17 00:00:00 2001
From: Phil Pirozhkov <pirjsuka@gmail.com>
Date: Fri, 7 Aug 2020 02:50:19 +0300
Subject: [PATCH 8/9] Enable MultipleMemoizedHelpers by default

Switching the cop on by default to match RSpec recommendations from its
docs and the community RSpec Style Guide recommendations.

    `let` _can_ enhance readability when used sparingly (1,2, or
    maybe 3 declarations) in any given example group, but that can
    quickly degrade with overuse. YMMV.

https://github.com/rspec/rspec-core/blob/5d87c28bb828ba14b54a0d8cfddf044894009314/lib/rspec/core/memoized_helpers.rb#L257

https://reddit.com/r/ruby/comments/73nrhk/ama_the_authors_of_effective_testing_with_rspec_3/dnsyanp/

https://rspec.rubystyle.guide/#let-blocks

Example change to dramatically reduce the number of used memoized
helpers without resorting to methods https://github.com/rubocop-hq/rubocop/pull/8447

There is no limit to the number of memoized helpers being used in
practice:

10 lets https://github.com/forem/forem/blob/master/spec/support/api_analytics_shared_examples.rb#L2
20 lets https://github.com/chef/chef/blob/master/spec/unit/provider/systemd_unit_spec.rb#L23
30 lets https://github.com/chef/chef/blob/master/spec/unit/policy_builder/policyfile_spec.rb#L24
40 lets https://github.com/diaspora/diaspora/blob/develop/spec/integration/migration_service_spec.rb#L7
50 lets https://github.com/chef/chef/blob/master/spec/functional/resource/dsc_script_spec.rb#L71

Allowing `subject` by default, i.e. subjects don't count towards the
number of memoized helpers, since there is a dedicated
`RSpec/MultipleSubjects` cop. Combination with it provides infinite
possibilities to tweak the maximum allowed number of memoized helpers to
meet the project style.
---
 config/default.yml                            |   4 +-
 .../cop/rspec/multiple_memoized_helpers.rb    |  20 ++--
 manual/cops_rspec.md                          |  24 ++--
 .../rspec/multiple_memoized_helpers_spec.rb   | 104 +++++++++---------
 4 files changed, 69 insertions(+), 83 deletions(-)

diff --git a/config/default.yml b/config/default.yml
index 61f67c9b7..946f854f8 100644
--- a/config/default.yml
+++ b/config/default.yml
@@ -396,8 +396,8 @@ RSpec/MultipleExpectations:
 
 RSpec/MultipleMemoizedHelpers:
   Description: Checks if example groups contain too many `let` and `subject` calls.
-  Enabled: false
-  AllowSubject: false
+  Enabled: true
+  AllowSubject: true
   Max: 5
   StyleGuide: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MultipleMemoizedHelpers
 
diff --git a/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb b/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
index 93b614c02..ea19b78ce 100644
--- a/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
+++ b/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
@@ -17,7 +17,7 @@ module RSpec
       #     let!(:baz) { [] }
       #     let(:qux) { [] }
       #     let(:quux) { [] }
-      #     subject(:quuz) { {} }
+      #     let(:quuz) { {} }
       #   end
       #
       #   describe MyClass do
@@ -28,7 +28,7 @@ module RSpec
       #     context 'when stuff' do
       #       let(:qux) { [] }
       #       let(:quux) { [] }
-      #       subject(:quuz) { {} }
+      #       let(:quuz) { {} }
       #     end
       #   end
       #
@@ -38,7 +38,7 @@ module RSpec
       #     let!(:baz) { [] }
       #     let(:qux) { [] }
       #     let(:quux) { [] }
-      #     subject(:quuz) { {} }
+      #     let(:quuz) { {} }
       #   end
       #
       #   describe MyClass do
@@ -51,7 +51,7 @@ module RSpec
       #     context 'when other stuff' do
       #       let(:qux) { [] }
       #       let(:quux) { [] }
-      #       subject(:quuz) { {} }
+      #       let(:quuz) { {} }
       #     end
       #   end
       #
@@ -59,9 +59,9 @@ module RSpec
       #
       #   # rubocop.yml
       #   # RSpec/MultipleMemoizedHelpers:
-      #   #   AllowSubject: true
+      #   #   AllowSubject: false
       #
-      #   # good
+      #   # bad - `subject` counts towards memoized helpers
       #   describe MyClass do
       #     subject { {} }
       #     let(:foo) { [] }
@@ -75,16 +75,12 @@ module RSpec
       #
       #   # rubocop.yml
       #   # RSpec/MultipleMemoizedHelpers:
-      #   #   Max: 0
+      #   #   Max: 1
       #
       #   # bad
       #   describe MyClass do
       #     let(:foo) { [] }
-      #   end
-      #
-      #   # good
-      #   describe MyClass do
-      #     def foo; []; end
+      #     let(:bar) { [] }
       #   end
       #
       class MultipleMemoizedHelpers < Base
diff --git a/manual/cops_rspec.md b/manual/cops_rspec.md
index 358b315d1..4d2a14dc2 100644
--- a/manual/cops_rspec.md
+++ b/manual/cops_rspec.md
@@ -2123,7 +2123,7 @@ Max | `1` | Integer
 
 Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged
 --- | --- | --- | --- | ---
-Disabled | Yes | No | - | -
+Enabled | Yes | No | - | -
 
 Checks if example groups contain too many `let` and `subject` calls.
 
@@ -2141,7 +2141,7 @@ describe MyClass do
   let!(:baz) { [] }
   let(:qux) { [] }
   let(:quux) { [] }
-  subject(:quuz) { {} }
+  let(:quuz) { {} }
 end
 
 describe MyClass do
@@ -2152,7 +2152,7 @@ describe MyClass do
   context 'when stuff' do
     let(:qux) { [] }
     let(:quux) { [] }
-    subject(:quuz) { {} }
+    let(:quuz) { {} }
   end
 end
 
@@ -2162,7 +2162,7 @@ describe MyClass do
   let!(:baz) { [] }
   let(:qux) { [] }
   let(:quux) { [] }
-  subject(:quuz) { {} }
+  let(:quuz) { {} }
 end
 
 describe MyClass do
@@ -2175,7 +2175,7 @@ describe MyClass do
   context 'when other stuff' do
     let(:qux) { [] }
     let(:quux) { [] }
-    subject(:quuz) { {} }
+    let(:quuz) { {} }
   end
 end
 ```
@@ -2184,9 +2184,9 @@ end
 ```ruby
 # rubocop.yml
 # RSpec/MultipleMemoizedHelpers:
-#   AllowSubject: true
+#   AllowSubject: false
 
-# good
+# bad - `subject` counts towards memoized helpers
 describe MyClass do
   subject { {} }
   let(:foo) { [] }
@@ -2201,16 +2201,12 @@ end
 ```ruby
 # rubocop.yml
 # RSpec/MultipleMemoizedHelpers:
-#   Max: 0
+#   Max: 1
 
 # bad
 describe MyClass do
   let(:foo) { [] }
-end
-
-# good
-describe MyClass do
-  def foo; []; end
+  let(:bar) { [] }
 end
 ```
 
@@ -2218,7 +2214,7 @@ end
 
 Name | Default value | Configurable values
 --- | --- | ---
-AllowSubject | `false` | Boolean
+AllowSubject | `true` | Boolean
 Max | `5` | Integer
 
 ### References
diff --git a/spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb b/spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb
index 24b5424e6..771e03493 100644
--- a/spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb
+++ b/spec/rubocop/cop/rspec/multiple_memoized_helpers_spec.rb
@@ -3,7 +3,7 @@
 RSpec.describe RuboCop::Cop::RSpec::MultipleMemoizedHelpers, :config do
   let(:cop_config) { { 'Max' => 1 } }
 
-  it 'flags an offense when using more than max `#let` calls' do
+  it 'flags excessive `#let`' do
     expect_offense(<<~RUBY)
       describe Foo do
       ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
@@ -13,83 +13,66 @@
     RUBY
   end
 
-  it 'flags an offense when using `#subject` without name' do
+  it 'flags excessive `#let!`' do
     expect_offense(<<~RUBY)
       describe Foo do
       ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
-        subject { Foo.new }
         let(:foo) { Foo.new }
+        let!(:bar) { Bar.new }
       end
     RUBY
   end
 
-  it 'flags an offense when using `#subject` with name' do
-    expect_offense(<<~RUBY)
-      describe Foo do
-      ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
-        subject(:foo) { Foo.new }
-        let(:bar) { Foo.new }
-      end
-    RUBY
-  end
-
-  it 'flags an offense when using `#let!`' do
-    expect_offense(<<~RUBY)
+  it 'ignores a reasonable number of memoized helpers' do
+    expect_no_offenses(<<~RUBY)
       describe Foo do
-      ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
         let(:foo) { Foo.new }
-        let!(:bar) { Foo.new }
       end
     RUBY
   end
 
-  it 'flags an offense when using `#subject!`' do
-    expect_offense(<<~RUBY)
+  it 'ignores overridden `#let`' do
+    expect_no_offenses(<<~RUBY)
       describe Foo do
-      ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
-        subject!(:foo) { Foo.new }
-        let(:bar) { Foo.new }
+        let(:foo) { Foo.new }
+        context do
+          let(:foo) { Foo.new(1) }
+          context do
+            let(:foo) { Foo.new(1, 2) }
+          end
+        end
       end
     RUBY
   end
 
-  it 'does not flag an offense when using <= max `#let` calls' do
+  it 'ignores `#subject`' do
     expect_no_offenses(<<~RUBY)
       describe Foo do
+        subject(:bar) { Bar.new }
         let(:foo) { Foo.new }
       end
     RUBY
   end
 
-  it 'ignores overridden variables' do
+  it 'ignores `#subject!`' do
     expect_no_offenses(<<~RUBY)
       describe Foo do
+        subject!(:bar) { Bar.new }
         let(:foo) { Foo.new }
-        context do
-          let(:foo) { Foo.new(1) }
-          context do
-            let(:foo) { Foo.new(1, 2) }
-          end
-        end
       end
     RUBY
   end
 
-  it 'ignores overridden nameless subjects' do
+  it 'ignores `#subject` without a name' do
     expect_no_offenses(<<~RUBY)
       describe Foo do
         subject { Foo.new }
-        context do
-          subject { Foo.new(1) }
-          context do
-            subject { Foo.new(1, 2) }
-          end
-        end
+        let(:bar) { Bar.new }
       end
     RUBY
   end
 
-  it 'flags an offense when too many `#let` calls are nested' do
+  it 'flags nested `#let`' do
     expect_offense(<<~RUBY)
       describe Foo do
         let(:foo) { Foo.new }
@@ -102,7 +85,7 @@
     RUBY
   end
 
-  it 'does not flag an offense when `#let` calls are distributed' do
+  it 'ignores distributed `#let`' do
     expect_no_offenses(<<~RUBY)
       describe Foo do
         context 'when bloo' do
@@ -116,38 +99,49 @@
     RUBY
   end
 
-  it 'does not flag an offense when using `#before`' do
-    expect_no_offenses(<<~RUBY)
-      describe Foo do
-        before { foo }
-      end
-    RUBY
-  end
-
   context 'when using AllowSubject configuration', :config do
-    let(:cop_config) { { 'Max' => 0, 'AllowSubject' => true } }
+    let(:cop_config) { { 'Max' => 1, 'AllowSubject' => false } }
 
-    it 'flags an offense when using `#let`' do
+    it 'flags `#subject` without name' do
       expect_offense(<<~RUBY)
         describe Foo do
-        ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [1/0]
+        ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
+          subject { Foo.new }
           let(:foo) { Foo.new }
         end
       RUBY
     end
 
-    it 'does not flag an offense when using `#subject` without a name' do
-      expect_no_offenses(<<~RUBY)
+    it 'flags `#subject`' do
+      expect_offense(<<~RUBY)
         describe Foo do
-          subject { Foo.new }
+        ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
+          subject(:foo) { Foo.new }
+          let(:bar) { Foo.new }
         end
       RUBY
     end
 
-    it 'does not flag an offense when using `#subject` with a name' do
+    it 'flags `#subject!`' do
+      expect_offense(<<~RUBY)
+        describe Foo do
+        ^^^^^^^^^^^^^^^ Example group has too many memoized helpers [2/1]
+          subject!(:foo) { Foo.new }
+          let(:bar) { Foo.new }
+        end
+      RUBY
+    end
+
+    it 'ignores overridden subjects' do
       expect_no_offenses(<<~RUBY)
         describe Foo do
-          subject(:foo) { Foo.new }
+          subject { Foo.new }
+          context do
+            subject { Foo.new(1) }
+            context do
+              subject { Foo.new(1, 2) }
+            end
+          end
         end
       RUBY
     end

From 986537f5872ea2c67abf189db8b5e97b223e6b08 Mon Sep 17 00:00:00 2001
From: Phil Pirozhkov <pirjsuka@gmail.com>
Date: Sun, 9 Aug 2020 14:53:57 +0300
Subject: [PATCH 9/9] Improve the performance of MultipleMemoizedHelpers

Fetching memoized helpers for each of the ancestors is not optimal, is
not optimal and has non-linear complexity.
---
 .../cop/rspec/multiple_memoized_helpers.rb    | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb b/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
index ea19b78ce..4ad7a0cf2 100644
--- a/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
+++ b/lib/rubocop/cop/rspec/multiple_memoized_helpers.rb
@@ -100,8 +100,14 @@ def on_block(node)
           add_offense(node, message: format(MSG, count: count, max: max))
         end
 
+        def on_new_investigation
+          @example_group_memoized_helpers = {}
+        end
+
         private
 
+        attr_reader :example_group_memoized_helpers
+
         def all_helpers(node)
           [
             *helpers(node),
@@ -110,13 +116,14 @@ def all_helpers(node)
         end
 
         def helpers(node)
-          variable_nodes(node).map do |variable_node|
-            if variable_node.block_type?
-              variable_definition?(variable_node.send_node)
-            else # block-pass (`let(:foo, &bar)`)
-              variable_definition?(variable_node)
+          @example_group_memoized_helpers[node] ||=
+            variable_nodes(node).map do |variable_node|
+              if variable_node.block_type?
+                variable_definition?(variable_node.send_node)
+              else # block-pass (`let(:foo, &bar)`)
+                variable_definition?(variable_node)
+              end
             end
-          end
         end
 
         def variable_nodes(node)