Enable `Style/RedundantBegin` cop to avoid newly adding redundant begin block

Currently we sometimes find a redundant begin block in code review
(e.g. https://github.com/rails/rails/pull/33604#discussion_r209784205).

I'd like to enable `Style/RedundantBegin` cop to avoid that, since
rescue/else/ensure are allowed inside do/end blocks in Ruby 2.5
(https://bugs.ruby-lang.org/issues/12906), so we'd probably meets with
that situation than before.

4 files changed, 30 insertions, 38 deletions

diff --git a/activesupport/lib/active_support/cache/file_store.rb b/activesupport/lib/active_support/cache/file_store.rb
index 53a2b07536..de1fb1886c 100644
--- a/activesupport/lib/active_support/cache/file_store.rb
+++ b/activesupport/lib/active_support/cache/file_store.rb
@@ -108,12 +108,10 @@ module ActiveSupport
         def lock_file(file_name, &block)
           if File.exist?(file_name)
             File.open(file_name, "r+") do |f|
-              begin
-                f.flock File::LOCK_EX
-                yield
-              ensure
-                f.flock File::LOCK_UN
-              end
+              f.flock File::LOCK_EX
+              yield
+            ensure
+              f.flock File::LOCK_UN
             end
           else
             yield
diff --git a/activesupport/lib/active_support/evented_file_update_checker.rb b/activesupport/lib/active_support/evented_file_update_checker.rb
index 97e982eb05..b2ae3dd274 100644
--- a/activesupport/lib/active_support/evented_file_update_checker.rb
+++ b/activesupport/lib/active_support/evented_file_update_checker.rb
@@ -57,11 +57,9 @@ module ActiveSupport
         # usage of attr_* macros for private attributes, but adds a lot of noise
         # to our test suite. Thus, we lazy load it and disable warnings locally.
         silence_warnings do
-          begin
-            require "listen"
-          rescue LoadError => e
-            raise LoadError, "Could not load the 'listen' gem. Add `gem 'listen'` to the development group of your Gemfile", e.backtrace
-          end
+          require "listen"
+        rescue LoadError => e
+          raise LoadError, "Could not load the 'listen' gem. Add `gem 'listen'` to the development group of your Gemfile", e.backtrace
         end
       end
       boot!
diff --git a/activesupport/lib/active_support/reloader.rb b/activesupport/lib/active_support/reloader.rb
index fea18e9712..2f81cd4f80 100644
--- a/activesupport/lib/active_support/reloader.rb
+++ b/activesupport/lib/active_support/reloader.rb
@@ -50,11 +50,9 @@ module ActiveSupport
     def self.reload!
       executor.wrap do
         new.tap do |instance|
-          begin
-            instance.run!
-          ensure
-            instance.complete!
-          end
+          instance.run!
+        ensure
+          instance.complete!
         end
       end
       prepare!
diff --git a/activesupport/lib/active_support/testing/parallelization.rb b/activesupport/lib/active_support/testing/parallelization.rb
index c5d3a88131..63440069b1 100644
--- a/activesupport/lib/active_support/testing/parallelization.rb
+++ b/activesupport/lib/active_support/testing/parallelization.rb
@@ -69,31 +69,29 @@ module ActiveSupport
       def start
         @pool = @queue_size.times.map do |worker|
           fork do
-            begin
-              DRb.stop_service
-
-              after_fork(worker)
-
-              queue = DRbObject.new_with_uri(@url)
-
-              while job = queue.pop
-                klass    = job[0]
-                method   = job[1]
-                reporter = job[2]
-                result   = Minitest.run_one_method(klass, method)
-
-                begin
-                  queue.record(reporter, result)
-                rescue DRb::DRbConnError
-                  result.failures.each do |failure|
-                    failure.exception = DRb::DRbRemoteError.new(failure.exception)
-                  end
-                  queue.record(reporter, result)
+            DRb.stop_service
+
+            after_fork(worker)
+
+            queue = DRbObject.new_with_uri(@url)
+
+            while job = queue.pop
+              klass    = job[0]
+              method   = job[1]
+              reporter = job[2]
+              result   = Minitest.run_one_method(klass, method)
+
+              begin
+                queue.record(reporter, result)
+              rescue DRb::DRbConnError
+                result.failures.each do |failure|
+                  failure.exception = DRb::DRbRemoteError.new(failure.exception)
                 end
+                queue.record(reporter, result)
               end
-            ensure
-              run_cleanup(worker)
             end
+          ensure
+            run_cleanup(worker)
           end
         end
       end