Add new Workit/RedundantBooleanConditional cop

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Add new `Workit/RedundantBooleanConditional` cop. ([@ydah])
+
 ## 0.5.0 - 2022-12-27
 
 - Deprecate `Workit/ComitteeAssertSchemaConfirm`. ([@ydah])

config/default.yml

@@ -32,6 +32,10 @@ Workit/NoopRescue:
   Description: "Check for suppress or ignore checked exception."
   Enabled: false
 
+Workit/RedundantBooleanConditional:
+  Description: "Checks for redundant boolean conditions."
+  Enabled: false
+
 Workit/RestrictOnSend:
   Description: |
     Check for `RESTRICT_ON_SEND` is defined if `on_send` or `after_send` are defined.

lib/rubocop/cop/workit/redundant_boolean_conditional.rb

@@ -0,0 +1,66 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module Workit
+      # Checks for redundant boolean conditions.
+      #
+      # @example
+      #   # bad
+      #   true if x == y
+      #
+      #   # good
+      #   x == y
+      #
+      class RedundantBooleanConditional < Base
+        extend AutoCorrector
+
+        MSG = "This conditional expression can just be replaced by `%<replaced>s`."
+
+        # @!method true_or_false?(node)
+        def_node_matcher :true_or_false?, <<~RUBY
+          ({:true :false})
+        RUBY
+
+        def on_if(node)
+          return unless redundant?(node)
+
+          add_offense(node, message: offense_message(node)) do |corrector|
+            corrector.replace(node, replacement_condition(node))
+          end
+        end
+
+        private
+
+        def offense_message(node)
+          replacement = replacement_condition(node)
+          replaced = node.elsif? ? "\n#{replacement}" : replacement
+
+          format(MSG, replaced: replaced)
+        end
+
+        def redundant?(node)
+          return false if node.else? || node.elsif? || node.elsif_conditional? || node.ternary?
+
+          node.if_branch.true_type? || node.if_branch.false_type?
+        end
+
+        def replacement_condition(node)
+          condition = node.condition.source
+          expression = invert_expression?(node) ? "!(#{condition})" : condition
+
+          node.elsif? ? indented_else_node(expression, node) : expression
+        end
+
+        def invert_expression?(node)
+          (!node.elsif_conditional? && (node.if? && node.if_branch.false_type?)) ||
+            (node.unless? && node.if_branch.true_type?)
+        end
+
+        def indented_else_node(expression, node)
+          "else\n#{indentation(node)}#{expression}"
+        end
+      end
+    end
+  end
+end

lib/workitcop.rb

@@ -10,6 +10,7 @@
 require_relative "rubocop/cop/workit/action_args"
 require_relative "rubocop/cop/workit/committee_expected_response_status_code"
 require_relative "rubocop/cop/workit/noop_rescue"
+require_relative "rubocop/cop/workit/redundant_boolean_conditional"
 require_relative "rubocop/cop/workit/restrict_on_send"
 require_relative "rubocop/cop/workit/rspec_capybara_match_style"
 require_relative "rubocop/cop/workit/rspec_capybara_predicate_matcher"

spec/rubocop/cop/workit/redundant_boolean_conditional_spec.rb

@@ -0,0 +1,99 @@
+# frozen_string_literal: true
+
+RSpec.describe RuboCop::Cop::Workit::RedundantBooleanConditional, :config do
+  it "registers an offense for if with true results" do
+    expect_offense(<<~RUBY)
+      true if x == y
+      ^^^^^^^^^^^^^^ This conditional expression can just be replaced by `x == y`.
+    RUBY
+
+    expect_correction(<<~RUBY)
+      x == y
+    RUBY
+  end
+
+  it "registers an offense for if with false results" do
+    expect_offense(<<~RUBY)
+      false if x == y
+      ^^^^^^^^^^^^^^^ This conditional expression can just be replaced by `!(x == y)`.
+    RUBY
+
+    expect_correction(<<~RUBY)
+      !(x == y)
+    RUBY
+  end
+
+  it "registers an offense for unless with true results" do
+    expect_offense(<<~RUBY)
+      true unless x == y
+      ^^^^^^^^^^^^^^^^^^ This conditional expression can just be replaced by `!(x == y)`.
+    RUBY
+
+    expect_correction(<<~RUBY)
+      !(x == y)
+    RUBY
+  end
+
+  it "registers an offense for unless with false results" do
+    expect_offense(<<~RUBY)
+      false unless x == y
+      ^^^^^^^^^^^^^^^^^^^ This conditional expression can just be replaced by `x == y`.
+    RUBY
+
+    expect_correction(<<~RUBY)
+      x == y
+    RUBY
+  end
+
+  it "registers an offense for if block with true results" do
+    expect_offense(<<~RUBY)
+      if x == y
+      ^^^^^^^^^ This conditional expression can just be replaced by `x == y`.
+        true
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      x == y
+    RUBY
+  end
+
+  it "registers an offense for if block with false results" do
+    expect_offense(<<~RUBY)
+      if x == y
+      ^^^^^^^^^ This conditional expression can just be replaced by `!(x == y)`.
+        false
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      !(x == y)
+    RUBY
+  end
+
+  it "registers an offense for unless block with true results" do
+    expect_offense(<<~RUBY)
+      unless x == y
+      ^^^^^^^^^^^^^ This conditional expression can just be replaced by `!(x == y)`.
+        true
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      !(x == y)
+    RUBY
+  end
+
+  it "registers an offense for unless block with false results" do
+    expect_offense(<<~RUBY)
+      unless x == y
+      ^^^^^^^^^^^^^ This conditional expression can just be replaced by `x == y`.
+        false
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      x == y
+    RUBY
+  end
+end