From da3fbed14bd802247f7cc088832a34ab637de078 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tobias=20B=C3=BChlmann?=
 <tbuehlmann@users.noreply.github.com>
Date: Sun, 9 Sep 2018 15:11:37 +0200
Subject: [PATCH] Use redis' default driver (#3956)

Redis stores its loaded drivers in `Redis::Connection.drivers` and uses the
last one of them when initializing a new client. Sidekiq always uses `'ruby'`
(or `Redis::Connection::Ruby`) per default, though.

With this commit we are following redis' default by passing the last
loaded driver per default (or a given `:driver`).
---
 lib/sidekiq/redis_connection.rb |  2 +-
 test/test_redis_connection.rb   | 31 +++++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/lib/sidekiq/redis_connection.rb b/lib/sidekiq/redis_connection.rb
index 66d3d428..98e86442 100644
--- a/lib/sidekiq/redis_connection.rb
+++ b/lib/sidekiq/redis_connection.rb
@@ -78,7 +78,7 @@ module Sidekiq
           opts.delete(:network_timeout)
         end
 
-        opts[:driver] ||= 'ruby'
+        opts[:driver] ||= Redis::Connection.drivers.last || 'ruby'
 
         # Issue #3303, redis-rb will silently retry an operation.
         # This can lead to duplicate jobs if Sidekiq::Client's LPUSH
diff --git a/test/test_redis_connection.rb b/test/test_redis_connection.rb
index c89ba7d6..bdb05ef6 100644
--- a/test/test_redis_connection.rb
+++ b/test/test_redis_connection.rb
@@ -144,6 +144,37 @@ class TestRedisConnection < Sidekiq::Test
         assert_equal 1, pool.instance_eval{ @timeout }
       end
     end
+
+    describe "driver" do
+      it "uses redis' ruby driver" do
+        pool = Sidekiq::RedisConnection.create
+        redis = pool.checkout
+
+        assert_equal Redis::Connection::Ruby, redis.instance_variable_get(:@client).driver
+      end
+
+      it "uses redis' default driver if there are many available" do
+        begin
+          redis_driver = Object.new
+          Redis::Connection.drivers << redis_driver
+
+          pool = Sidekiq::RedisConnection.create
+          redis = pool.checkout
+
+          assert_equal redis_driver, redis.instance_variable_get(:@client).driver
+        ensure
+          Redis::Connection.drivers.pop
+        end
+      end
+
+      it "uses a given :driver" do
+        redis_driver = Object.new
+        pool = Sidekiq::RedisConnection.create(:driver => redis_driver)
+        redis = pool.checkout
+
+        assert_equal redis_driver, redis.instance_variable_get(:@client).driver
+      end
+    end
   end
 
   describe ".determine_redis_provider" do