Revert "Merge pull request #31447 from fatkodima/redis_cache-connection_pool"

This reverts commit ac74e2c521f6ddc0eac02d74a1313261bcc1d60f, reversing
changes made to ffdb06136152b3c5f7f4a93ca5928e16e755d228.

5 files changed, 24 insertions, 104 deletions

diff --git a/Gemfile b/Gemfile
index 18e014e72f..b1d59ec077 100644
--- a/Gemfile
+++ b/Gemfile
@@ -52,7 +52,7 @@ end
 gem "dalli", ">= 2.2.1"
 gem "listen", ">= 3.0.5", "< 3.2", require: false
 gem "libxml-ruby", platforms: :ruby
-gem "connection_pool", require: false
+gem "connection_pool"
 
 # for railties app_generator_test
 gem "bootsnap", ">= 1.1.0", require: false
diff --git a/activesupport/lib/active_support/cache.rb b/activesupport/lib/active_support/cache.rb
index d221b36365..2d038dba77 100644
--- a/activesupport/lib/active_support/cache.rb
+++ b/activesupport/lib/active_support/cache.rb
@@ -160,23 +160,6 @@ module ActiveSupport
       attr_reader :silence, :options
       alias :silence? :silence
 
-      class << self
-        private
-          def retrieve_pool_options(options)
-            {}.tap do |pool_options|
-              pool_options[:size] = options[:pool_size] if options[:pool_size]
-              pool_options[:timeout] = options[:pool_timeout] if options[:pool_timeout]
-            end
-          end
-
-          def ensure_connection_pool_added!
-            require "connection_pool"
-          rescue LoadError => e
-            $stderr.puts "You don't have connection_pool installed in your application. Please add it to your Gemfile and run bundle install"
-            raise e
-          end
-      end
-
       # Creates a new cache. The options will be passed to any write method calls
       # except for <tt>:namespace</tt> which can be used to set the global
       # namespace for the cache.
diff --git a/activesupport/lib/active_support/cache/mem_cache_store.rb b/activesupport/lib/active_support/cache/mem_cache_store.rb
index 2840781dde..cae0d44e7d 100644
--- a/activesupport/lib/active_support/cache/mem_cache_store.rb
+++ b/activesupport/lib/active_support/cache/mem_cache_store.rb
@@ -63,12 +63,21 @@ module ActiveSupport
         addresses = addresses.flatten
         options = addresses.extract_options!
         addresses = ["localhost:11211"] if addresses.empty?
-        pool_options = retrieve_pool_options(options)
+
+        pool_options = {}
+        pool_options[:size] = options[:pool_size] if options[:pool_size]
+        pool_options[:timeout] = options[:pool_timeout] if options[:pool_timeout]
 
         if pool_options.empty?
           Dalli::Client.new(addresses, options)
         else
-          ensure_connection_pool_added!
+          begin
+            require "connection_pool"
+          rescue LoadError => e
+            $stderr.puts "You don't have connection_pool installed in your application. Please add it to your Gemfile and run bundle install"
+            raise e
+          end
+
           ConnectionPool.new(pool_options) { Dalli::Client.new(addresses, options.merge(threadsafe: false)) }
         end
       end
diff --git a/activesupport/lib/active_support/cache/redis_cache_store.rb b/activesupport/lib/active_support/cache/redis_cache_store.rb
index c4cd9c4761..1de98dcd6c 100644
--- a/activesupport/lib/active_support/cache/redis_cache_store.rb
+++ b/activesupport/lib/active_support/cache/redis_cache_store.rb
@@ -20,31 +20,6 @@ require "active_support/core_ext/marshal"
 
 module ActiveSupport
   module Cache
-    module ConnectionPoolLike
-      def with
-        yield self
-      end
-    end
-
-    ::Redis.include(ConnectionPoolLike)
-
-    class RedisDistributedWithConnectionPool < ::Redis::Distributed
-      def add_node(options)
-        pool_options = {}
-        pool_options[:size] = options[:pool_size] if options[:pool_size]
-        pool_options[:timeout] = options[:pool_timeout] if options[:pool_timeout]
-
-        if pool_options.empty?
-          super
-        else
-          options = { url: options } if options.is_a?(String)
-          options = @default_options.merge(options)
-          pool = ConnectionPool.new(pool_options) { ::Redis.new(options) }
-          @ring.add_node(pool)
-        end
-      end
-    end
-
     # Redis cache store.
     #
     # Deployment note: Take care to use a *dedicated Redis cache* rather
@@ -147,7 +122,7 @@ module ActiveSupport
 
         private
           def build_redis_distributed_client(urls:, **redis_options)
-            RedisDistributedWithConnectionPool.new([], DEFAULT_REDIS_OPTIONS.merge(redis_options)).tap do |dist|
+            ::Redis::Distributed.new([], DEFAULT_REDIS_OPTIONS.merge(redis_options)).tap do |dist|
               urls.each { |u| dist.add_node url: u }
             end
           end
@@ -197,7 +172,7 @@ module ActiveSupport
       end
 
       def redis
-        @redis ||= wrap_in_connection_pool(self.class.build_redis(**redis_options))
+        @redis ||= self.class.build_redis(**redis_options)
       end
 
       def inspect
@@ -236,7 +211,7 @@ module ActiveSupport
         instrument :delete_matched, matcher do
           case matcher
           when String
-            redis.with { |c| c.eval DELETE_GLOB_LUA, [], [namespace_key(matcher, options)] }
+            redis.eval DELETE_GLOB_LUA, [], [namespace_key(matcher, options)]
           else
             raise ArgumentError, "Only Redis glob strings are supported: #{matcher.inspect}"
           end
@@ -254,7 +229,7 @@ module ActiveSupport
       def increment(name, amount = 1, options = nil)
         instrument :increment, name, amount: amount do
           failsafe :increment do
-            redis.with { |c| c.incrby normalize_key(name, options), amount }
+            redis.incrby normalize_key(name, options), amount
           end
         end
       end
@@ -270,7 +245,7 @@ module ActiveSupport
       def decrement(name, amount = 1, options = nil)
         instrument :decrement, name, amount: amount do
           failsafe :decrement do
-            redis.with { |c| c.decrby normalize_key(name, options), amount }
+            redis.decrby normalize_key(name, options), amount
           end
         end
       end
@@ -292,7 +267,7 @@ module ActiveSupport
           if namespace = merged_options(options)[namespace]
             delete_matched "*", namespace: namespace
           else
-            redis.with { |c| c.flushdb }
+            redis.flushdb
           end
         end
       end
@@ -308,21 +283,6 @@ module ActiveSupport
       end
 
       private
-        def wrap_in_connection_pool(redis_connection)
-          if redis_connection.is_a?(::Redis)
-            pool_options = self.class.send(:retrieve_pool_options, redis_options)
-
-            if pool_options.empty?
-              redis_connection
-            else
-              self.class.send(:ensure_connection_pool_added!)
-              ConnectionPool.new(pool_options) { redis_connection }
-            end
-          else
-            redis_connection
-          end
-        end
-
         def set_redis_capabilities
           case redis
           when Redis::Distributed
@@ -338,7 +298,7 @@ module ActiveSupport
         # Read an entry from the cache.
         def read_entry(key, options = nil)
           failsafe :read_entry do
-            deserialize_entry redis.with { |c| c.get(key) }
+            deserialize_entry redis.get(key)
           end
         end
 
@@ -349,7 +309,7 @@ module ActiveSupport
           keys = names.map { |name| normalize_key(name, options) }
 
           values = failsafe(:read_multi_mget, returning: {}) do
-            redis.with { |c| c.mget(*keys) }
+            redis.mget(*keys)
           end
 
           names.zip(values).each_with_object({}) do |(name, value), results|
@@ -381,9 +341,9 @@ module ActiveSupport
               modifiers[:nx] = unless_exist
               modifiers[:px] = (1000 * expires_in.to_f).ceil if expires_in
 
-              redis.with { |c| c.set key, value, modifiers }
+              redis.set key, value, modifiers
             else
-              redis.with { |c| c.set key, value }
+              redis.set key, value
             end
           end
         end
@@ -391,7 +351,7 @@ module ActiveSupport
         # Delete an entry from the cache.
         def delete_entry(key, options)
           failsafe :delete_entry, returning: false do
-            redis.with { |c| c.del key }
+            redis.del key
           end
         end
 
@@ -400,7 +360,7 @@ module ActiveSupport
           if entries.any?
             if mset_capable? && expires_in.nil?
               failsafe :write_multi_entries do
-                redis.with { |c| c.mapped_mset(entries) }
+                redis.mapped_mset(entries)
               end
             else
               super
diff --git a/activesupport/test/cache/stores/redis_cache_store_test.rb b/activesupport/test/cache/stores/redis_cache_store_test.rb
index 7c1286a115..62752d2c65 100644
--- a/activesupport/test/cache/stores/redis_cache_store_test.rb
+++ b/activesupport/test/cache/stores/redis_cache_store_test.rb
@@ -8,18 +8,6 @@ require_relative "../behaviors"
 module ActiveSupport::Cache::RedisCacheStoreTests
   DRIVER = %w[ ruby hiredis ].include?(ENV["REDIS_DRIVER"]) ? ENV["REDIS_DRIVER"] : "hiredis"
 
-  # Emulates a latency on Redis's back-end for the key latency to facilitate
-  # connection pool testing.
-  class SlowRedis < Redis
-    def get(key, options = {})
-      if key =~ /latency/
-        sleep 3
-      else
-        super
-      end
-    end
-  end
-
   class LookupTest < ActiveSupport::TestCase
     test "may be looked up as :redis_cache_store" do
       assert_kind_of ActiveSupport::Cache::RedisCacheStore,
@@ -122,26 +110,6 @@ module ActiveSupport::Cache::RedisCacheStoreTests
     include AutoloadingCacheBehavior
   end
 
-  class RedisCacheStoreConnectionPoolBehaviourTest < StoreTest
-    include ConnectionPoolBehavior
-
-    private
-
-      def store
-        :redis_cache_store
-      end
-
-      def emulating_latency
-        old_redis = Object.send(:remove_const, :Redis)
-        Object.const_set(:Redis, SlowRedis)
-
-        yield
-      ensure
-        Object.send(:remove_const, :Redis)
-        Object.const_set(:Redis, old_redis)
-      end
-  end
-
   # Separate test class so we can omit the namespace which causes expected,
   # appropriate complaints about incompatible string encodings.
   class KeyEncodingSafetyTest < StoreTest