RedisCacheStore: don't pass url if it's nil

In 5.0 it will prevent `$REDIS_URL` from being used.

activesupport/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Redis cache store is now compatible with redis-rb 5.0.
+
+    *Jean Boussier*
+
 *   Log a warning if `ActiveSupport::Cache` is given an expiration in the past.
 
     *Trevor Turk*

activesupport/lib/active_support/cache/redis_cache_store.rb

@@ -84,9 +84,11 @@ def build_redis(redis: nil, url: nil, **redis_options) # :nodoc:
           elsif redis
             redis
           elsif urls.size > 1
-            build_redis_distributed_client urls: urls, **redis_options
+            build_redis_distributed_client(urls: urls, **redis_options)
+          elsif urls.empty?
+            build_redis_client(**redis_options)
           else
-            build_redis_client url: urls.first, **redis_options
+            build_redis_client(url: urls.first, **redis_options)
           end
         end
 
@@ -97,8 +99,8 @@ def build_redis_distributed_client(urls:, **redis_options)
             end
           end
 
-          def build_redis_client(url:, **redis_options)
-            ::Redis.new DEFAULT_REDIS_OPTIONS.merge(redis_options.merge(url: url))
+          def build_redis_client(**redis_options)
+            ::Redis.new(DEFAULT_REDIS_OPTIONS.merge(redis_options))
           end
       end
 

activesupport/test/cache/stores/redis_cache_store_test.rb

@@ -46,7 +46,6 @@ class LookupTest < ActiveSupport::TestCase
   class InitializationTest < ActiveSupport::TestCase
     test "omitted URL uses Redis client with default settings" do
       assert_called_with Redis, :new, [
-        url: nil,
         connect_timeout: 20, read_timeout: 1, write_timeout: 1,
         reconnect_attempts: 0
       ] do
@@ -56,7 +55,6 @@ class InitializationTest < ActiveSupport::TestCase
 
     test "no URLs uses Redis client with default settings" do
       assert_called_with Redis, :new, [
-        url: nil,
         connect_timeout: 20, read_timeout: 1, write_timeout: 1,
         reconnect_attempts: 0
       ] do