Fix Redis version determination for predis replication connection (#522)

* Add check that redis_version is set

* Fetch Redis server info for replicated connections

* change style

* Update CHANGELOG.md

---------

Co-authored-by: Till Krüss <[email protected]>

Author: yatsukhnenko

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## Unreleased
 
-- Fixed `wp_cache_flush_group` issue with Predis and replication connection
+- Fixed issues with Predis and replication connections
 - Fixed rare fatal error in `show_error_and_die()` (one more time)
 
 ## 2.5.2

includes/object-cache.php

@@ -1139,22 +1139,16 @@ protected function connect_using_hhvm( $parameters ) {
      * @return void
      */
     public function fetch_info() {
-        $options = method_exists( $this->redis, 'getOptions' )
-            ? $this->redis->getOptions()
-            : new stdClass();
-
-        if ( isset( $options->replication ) && $options->replication ) {
-            return;
-        }
-
         if ( defined( 'WP_REDIS_CLUSTER' ) ) {
             $connectionId = is_string( WP_REDIS_CLUSTER )
                 ? 'SERVER'
                 : current( $this->build_cluster_connection_array() );
 
-            $info = $this->determine_client() === 'predis'
+            $info = $this->is_predis()
                 ? $this->redis->getClientBy( 'id', $connectionId )->info()
                 : $this->redis->info( $connectionId );
+        } else if ($this->is_predis() && $this->redis->getConnection() instanceof Predis\Connection\Replication\MasterSlaveReplication) {
+            $info = $this->redis->getClientBy( 'role' , 'master' )->info();
         } else {
             $info = $this->redis->info();
         }
@@ -1888,7 +1882,7 @@ protected function lua_flush_closure( $salt, $escape = true ) {
                 return i
 LUA;
 
-            if ( version_compare( $this->redis_version(), '5', '<' ) && version_compare( $this->redis_version(), '3.2', '>=' ) ) {
+            if ( isset($this->redis_version) && version_compare( $this->redis_version, '5', '<' ) && version_compare( $this->redis_version, '3.2', '>=' ) ) {
                 $script = 'redis.replicate_commands()' . "\n" . $script;
             }
 
@@ -1940,7 +1934,7 @@ function ( $group ) {
                 until 0 == cur
                 return i
 LUA;
-            if ( version_compare( $this->redis_version(), '5', '<' ) && version_compare( $this->redis_version(), '3.2', '>=' ) ) {
+            if ( isset($this->redis_version) && version_compare( $this->redis_version, '5', '<' ) && version_compare( $this->redis_version, '3.2', '>=' ) ) {
                 $script = 'redis.replicate_commands()' . "\n" . $script;
             }