[fixes #8385] Remove Lint/EnsureReturn autocorrection and flag multi-…

…value returns

It is not possible to autocorrect a `return` in an `ensure`, as not only does it
modify control flow without the ensure block, it also overrides the normal return
value

This reverts #7934

docs/modules/ROOT/pages/cops_lint.adoc

@@ -1035,32 +1035,48 @@ end
 |===
 
 This cop checks for `return` from an `ensure` block.
-Explicit return from an ensure block alters the control flow
-as the return will take precedence over any exception being raised,
+`return` from an ensure block is a dangerous code smell as it
+will take precedence over any exception being raised,
 and the exception will be silently thrown away as if it were rescued.
 
+If you want to rescue some (or all) exceptions, best to do it explicitly
+
 === Examples
 
 [source,ruby]
 ----
 # bad
 
-begin
+def foo
   do_something
 ensure
-  do_something_else
-  return
+  cleanup
+  return self
 end
 ----
 
 [source,ruby]
 ----
 # good
 
-begin
+def foo
   do_something
+  self
 ensure
-  do_something_else
+  cleanup
+end
+
+# also good
+
+def foo
+  begin
+    do_something
+  rescue SomeException
+    # Let's ignore this exception
+  end
+  self
+ensure
+  cleanup
 end
 ----
 

lib/rubocop/cop/lint/ensure_return.rb

@@ -4,57 +4,55 @@ module RuboCop
   module Cop
     module Lint
       # This cop checks for `return` from an `ensure` block.
-      # Explicit return from an ensure block alters the control flow
-      # as the return will take precedence over any exception being raised,
+      # `return` from an ensure block is a dangerous code smell as it
+      # will take precedence over any exception being raised,
       # and the exception will be silently thrown away as if it were rescued.
       #
+      # If you want to rescue some (or all) exceptions, best to do it explicitly
+      #
       # @example
       #
       #   # bad
       #
-      #   begin
+      #   def foo
       #     do_something
       #   ensure
-      #     do_something_else
-      #     return
+      #     cleanup
+      #     return self
       #   end
       #
       # @example
       #
       #   # good
       #
-      #   begin
+      #   def foo
       #     do_something
+      #     self
+      #   ensure
+      #     cleanup
+      #   end
+      #
+      #   # also good
+      #
+      #   def foo
+      #     begin
+      #       do_something
+      #     rescue SomeException
+      #       # Let's ignore this exception
+      #     end
+      #     self
       #   ensure
-      #     do_something_else
+      #     cleanup
       #   end
-      class EnsureReturn < Cop
+      class EnsureReturn < Base
+        extend AutoCorrector
         include RangeHelp
 
         MSG = 'Do not return from an `ensure` block.'
 
         def on_ensure(node)
-          ensure_body = node.body
-
-          return unless ensure_body
-
-          ensure_body.each_node(:return) do |return_node|
-            next if return_node.arguments.size >= 2
-
-            add_offense(return_node, location: :keyword)
-          end
-        end
-
-        def autocorrect(node)
-          lambda do |corrector|
-            if node.arguments?
-              corrector.replace(node, node.source.gsub(/return\s*/, ''))
-            else
-              range = range_by_whole_lines(
-                node.loc.expression, include_final_newline: true
-              )
-              corrector.remove(range)
-            end
+          node.body&.each_node(:return) do |return_node|
+            add_offense(return_node)
           end
         end
       end

spec/rubocop/cop/lint/ensure_return_spec.rb

@@ -14,53 +14,43 @@
       end
     RUBY
 
-    expect_correction(<<~RUBY)
-      begin
-        something
-      ensure
-        file.close
-      end
-    RUBY
+    expect_no_corrections
   end
 
   it 'registers an offense and corrects for return with argument in ensure' do
     expect_offense(<<~RUBY)
       begin
         foo
       ensure
-        bar
         return baz
-        ^^^^^^ Do not return from an `ensure` block.
+        ^^^^^^^^^^ Do not return from an `ensure` block.
       end
     RUBY
 
-    expect_correction(<<~RUBY)
-      begin
-        foo
-      ensure
-        bar
-        baz
-      end
-    RUBY
+    expect_no_corrections
   end
 
-  it 'does not register an offense for return outside ensure' do
-    expect_no_offenses(<<~RUBY)
+  it 'registers an offense when returning multiple values in `ensure`' do
+    expect_offense(<<~RUBY)
       begin
         something
-        return
       ensure
-        file.close
+        do_something
+        return foo, bar
+        ^^^^^^^^^^^^^^^ Do not return from an `ensure` block.
       end
     RUBY
+
+    expect_no_corrections
   end
 
-  it "doesn't register an offense when returning multiple values in `ensure`" do
+  it 'does not register an offense for return outside ensure' do
     expect_no_offenses(<<~RUBY)
       begin
         something
+        return
       ensure
-        return foo, bar
+        file.close
       end
     RUBY
   end