Merge pull request #931 from flippercloud/redis-with

Horrible hackish thing to fix redis less than 4.7 with active record 7.1

Author: jnunemaker

lib/flipper/adapters/redis_shared/methods.rb

@@ -1,8 +1,63 @@
 module Flipper
   module Adapters
     module RedisShared
+      private
+
+      # Safely executes a block with a Redis connection, handling compatibility
+      # issues between different Redis client versions and Rails versions.
+      #
+      # This method exists to fix a compatibility issue between Rails 7.1.* and
+      # Redis versions below 4.7.0. The issue occurs because:
+      #
+      # 1. In Redis versions below 4.7.0, the `with` method is not defined on
+      #    the Redis client, so Flipper would fall back to `yield(@client)`
+      # 2. However, Rails 7.1.* introduced `Object#with` via ActiveSupport,
+      #    which shadows the Redis client's `with` method
+      # 3. Rails 7.1.*'s `Object#with` doesn't pass `self` to the block parameter
+      #    (this was fixed in Rails 7.2.0), causing the block parameter to be `nil`
+      #
+      # This method ensures that:
+      # - For Redis >= 4.7.0: Uses the Redis client's native `with` method
+      # - For ConnectionPool: Uses the ConnectionPool's `with` method
+      # - For Redis < 4.7.0: Falls back to `yield(@client)` to avoid the Rails
+      #   ActiveSupport `Object#with` method
+      #
+      # @see https://github.com/redis/redis-rb/blob/master/CHANGELOG.md#470
+      # @see https://github.com/rails/rails/pull/46681
+      # @see https://github.com/rails/rails/pull/50470
       def with_connection(&block)
-        @client.respond_to?(:with) ? @client.with(&block) : yield(@client)
+        if client_has_correct_with_method?
+          @client.with(&block)
+        else
+          yield(@client)
+        end
+      end
+
+      # Determines if the Redis client has a safe `with` method that can be used
+      # without conflicts with Rails ActiveSupport's `Object#with`.
+      #
+      # This method checks for:
+      # 1. ConnectionPool instances (which have their own `with` method)
+      # 2. Redis instances with version >= 4.7.0 (which have a proper `with` method)
+      #
+      # The method caches its result to avoid repeated checks.
+      #
+      # @return [Boolean] true if the client has a safe `with` method, false otherwise
+      def client_has_correct_with_method?
+        return @client_has_correct_with_method if defined?(@client_has_correct_with_method)
+
+        @client_has_correct_with_method = @client.respond_to?(:with) && (client_is_connection_pool? || client_is_redis_that_has_with?)
+      rescue
+        @client_has_correct_with_method = false
+      end
+
+      def client_is_connection_pool?
+        defined?(ConnectionPool) && @client.is_a?(ConnectionPool)
+      end
+
+      def client_is_redis_that_has_with?
+        @client.is_a?(::Redis) && defined?(::Redis::VERSION) &&
+          ::Gem::Version.new(::Redis::VERSION) >= ::Gem::Version.new('4.7.0')
       end
     end
   end