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.

5 files changed, 19 insertions, 29 deletions

diff --git a/actionpack/lib/action_controller/metal/instrumentation.rb b/actionpack/lib/action_controller/metal/instrumentation.rb
index be9449629f..51fac08749 100644
--- a/actionpack/lib/action_controller/metal/instrumentation.rb
+++ b/actionpack/lib/action_controller/metal/instrumentation.rb
@@ -30,13 +30,11 @@ module ActionController
       ActiveSupport::Notifications.instrument("start_processing.action_controller", raw_payload.dup)
 
       ActiveSupport::Notifications.instrument("process_action.action_controller", raw_payload) do |payload|
-        begin
-          result = super
+        super.tap do
           payload[:status] = response.status
-          result
-        ensure
-          append_info_to_payload(payload)
         end
+      ensure
+        append_info_to_payload(payload)
       end
     end
 
diff --git a/actionpack/lib/action_dispatch/middleware/callbacks.rb b/actionpack/lib/action_dispatch/middleware/callbacks.rb
index 5b2ad36dd5..87fe19225b 100644
--- a/actionpack/lib/action_dispatch/middleware/callbacks.rb
+++ b/actionpack/lib/action_dispatch/middleware/callbacks.rb
@@ -24,10 +24,8 @@ module ActionDispatch
     def call(env)
       error = nil
       result = run_callbacks :call do
-        begin
-          @app.call(env)
-        rescue => error
-        end
+        @app.call(env)
+      rescue => error
       end
       raise error if error
       result
diff --git a/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb b/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
index eadb59173d..61773d97a2 100644
--- a/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
+++ b/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
@@ -48,11 +48,9 @@ module ActionDispatch
         wrapper = ExceptionWrapper.new(backtrace_cleaner, exception)
 
         @interceptors.each do |interceptor|
-          begin
-            interceptor.call(request, exception)
-          rescue Exception
-            log_error(request, wrapper)
-          end
+          interceptor.call(request, exception)
+        rescue Exception
+          log_error(request, wrapper)
         end
       end
 
diff --git a/actionpack/lib/action_dispatch/middleware/host_authorization.rb b/actionpack/lib/action_dispatch/middleware/host_authorization.rb
index 48f7c25216..447b70112a 100644
--- a/actionpack/lib/action_dispatch/middleware/host_authorization.rb
+++ b/actionpack/lib/action_dispatch/middleware/host_authorization.rb
@@ -21,13 +21,11 @@ module ActionDispatch
 
       def allows?(host)
         @hosts.any? do |allowed|
-          begin
-            allowed === host
-          rescue
-            # IPAddr#=== raises an error if you give it a hostname instead of
-            # IP. Treat similar errors as blocked access.
-            false
-          end
+          allowed === host
+        rescue
+          # IPAddr#=== raises an error if you give it a hostname instead of
+          # IP. Treat similar errors as blocked access.
+          false
         end
       end
 
diff --git a/actionpack/lib/action_dispatch/middleware/remote_ip.rb b/actionpack/lib/action_dispatch/middleware/remote_ip.rb
index 35158f9062..a5667573f4 100644
--- a/actionpack/lib/action_dispatch/middleware/remote_ip.rb
+++ b/actionpack/lib/action_dispatch/middleware/remote_ip.rb
@@ -162,14 +162,12 @@ module ActionDispatch
         # Split the comma-separated list into an array of strings.
         ips = header.strip.split(/[,\s]+/)
         ips.select do |ip|
-          begin
-            # Only return IPs that are valid according to the IPAddr#new method.
-            range = IPAddr.new(ip).to_range
-            # We want to make sure nobody is sneaking a netmask in.
-            range.begin == range.end
-          rescue ArgumentError
-            nil
-          end
+          # Only return IPs that are valid according to the IPAddr#new method.
+          range = IPAddr.new(ip).to_range
+          # We want to make sure nobody is sneaking a netmask in.
+          range.begin == range.end
+        rescue ArgumentError
+          nil
         end
       end