Merge pull request #8822 from koic/make_style_redundant_begin_aware_o…

…f_begin_without_rescue

Make `Style/RedundantBegin` aware of `begin` without `rescue`

CHANGELOG.md

@@ -7,6 +7,7 @@
 * [#8796](https://github.com/rubocop-hq/rubocop/pull/8796): Add new `Lint/HashCompareByIdentity` cop. ([@fatkodima][])
 * [#8668](https://github.com/rubocop-hq/rubocop/pull/8668): Add new `Lint/RedundantSafeNavigation` cop. ([@fatkodima][])
 * [#8842](https://github.com/rubocop-hq/rubocop/issues/8842): Add notification about cache being used to debug mode. ([@hatkyinc2][])
+* [#8822](https://github.com/rubocop-hq/rubocop/pull/8822): Make `Style/RedundantBegin` aware of `begin` without `rescue` or `ensure`. ([@koic][])
 
 ### Bug fixes
 

docs/modules/ROOT/pages/cops_style.adoc

@@ -7557,6 +7557,14 @@ rescue StandardError => e
   something
 end
 
+# bad
+begin
+  do_something
+end
+
+# good
+do_something
+
 # bad
 # When using Ruby 2.5 or later.
 do_something do

lib/rubocop/cop/style/redundant_begin.rb

@@ -28,6 +28,14 @@ module Style
       #   end
       #
       #   # bad
+      #   begin
+      #     do_something
+      #   end
+      #
+      #   # good
+      #   do_something
+      #
+      #   # bad
       #   # When using Ruby 2.5 or later.
       #   do_something do
       #     begin
@@ -60,7 +68,9 @@ class RedundantBegin < Base
         MSG = 'Redundant `begin` block detected.'
 
         def on_def(node)
-          check(node)
+          return unless node.body&.kwbegin_type?
+
+          register_offense(node.body)
         end
         alias on_defs on_def
 
@@ -69,18 +79,26 @@ def on_block(node)
 
           return if node.send_node.lambda_literal?
           return if node.braces?
+          return unless node.body&.kwbegin_type?
 
-          check(node)
+          register_offense(node.body)
         end
 
-        private
+        def on_kwbegin(node)
+          return if node.parent&.assignment?
 
-        def check(node)
-          return unless node.body&.kwbegin_type?
+          first_child = node.children.first
+          return if first_child.rescue_type? || first_child.ensure_type?
+
+          register_offense(node)
+        end
+
+        private
 
-          add_offense(node.body.loc.begin) do |corrector|
-            corrector.remove(node.body.loc.begin)
-            corrector.remove(node.body.loc.end)
+        def register_offense(node)
+          add_offense(node.loc.begin) do |corrector|
+            corrector.remove(node.loc.begin)
+            corrector.remove(node.loc.end)
           end
         end
       end

spec/rubocop/cop/style/redundant_begin_spec.rb

@@ -155,6 +155,55 @@ def method
     RUBY
   end
 
+  it 'registers an offense and corrects when using `begin` without `rescue` or `ensure`' do
+    expect_offense(<<~RUBY)
+      begin
+      ^^^^^ Redundant `begin` block detected.
+        do_something
+      end
+    RUBY
+
+    expect_correction("\n  do_something\n\n")
+  end
+
+  it 'does not register an offense when using `begin` with `rescue`' do
+    expect_no_offenses(<<~RUBY)
+      begin
+        do_something
+      rescue
+        handle_exception
+      end
+    RUBY
+  end
+
+  it 'does not register an offense when using `begin` with `ensure`' do
+    expect_no_offenses(<<~RUBY)
+      begin
+        do_something
+      ensure
+        finalize
+      end
+    RUBY
+  end
+
+  it 'does not register an offense when using `begin` for assignment' do
+    expect_no_offenses(<<~RUBY)
+      var = begin
+        foo
+        bar
+      end
+    RUBY
+  end
+
+  it 'does not register an offense when using `begin` for or assignment' do
+    expect_no_offenses(<<~RUBY)
+      var ||= begin
+        foo
+        bar
+      end
+    RUBY
+  end
+
   context '< Ruby 2.5', :ruby24 do
     it 'accepts a do-end block with a begin-end' do
       expect_no_offenses(<<~RUBY)