[8.x] Fix possible out of memory error when deleting values by reference key from cache in Redis driver

Author: Denis Kuzmenchuk

src/Illuminate/Cache/RedisTaggedCache.php

@@ -178,13 +178,26 @@ protected function deleteKeysByReference($reference)
      */
     protected function deleteValues($referenceKey)
     {
-        $values = array_unique($this->store->connection()->smembers($referenceKey));
+        $cursor = $defaultCursorValue = '0';
+
+        do {
+            [$cursor, $valuesChunk] = $this->store->connection()->sscan(
+                $referenceKey, $cursor, ['match' => '*', 'count' => 1000]
+            );
+
+            // PhpRedis client returns false if set does not exist or empty. Destruction on false stores null
+            // in each variable. If valuesChunk is null, it means that there is no results from sscan command.
+            // Iteration over set could be finished.
+            if ($valuesChunk === null) {
+                break;
+            }
+
+            $valuesChunk = array_unique($valuesChunk);
 
-        if (count($values) > 0) {
-            foreach (array_chunk($values, 1000) as $valuesChunk) {
+            if (count($valuesChunk) > 0) {
                 $this->store->connection()->del(...$valuesChunk);
             }
-        }
+        } while (((string) $cursor) !== $defaultCursorValue);
     }
 
     /**

tests/Cache/CacheTaggedCacheTest.php

@@ -267,16 +267,16 @@ public function testRedisCacheTagsCanBeFlushed()
         $store->shouldReceive('connection')->andReturn($conn = m::mock(stdClass::class));
 
         // Forever tag keys
-        $conn->shouldReceive('smembers')->once()->with('prefix:foo:forever_ref')->andReturn(['key1', 'key2']);
-        $conn->shouldReceive('smembers')->once()->with('prefix:bar:forever_ref')->andReturn(['key3']);
+        $conn->shouldReceive('sscan')->once()->with('prefix:foo:forever_ref', '0', ['match' => '*', 'count' => 1000])->andReturn(['0', ['key1', 'key2']]);
+        $conn->shouldReceive('sscan')->once()->with('prefix:bar:forever_ref', '0', ['match' => '*', 'count' => 1000])->andReturn(['0', ['key3']]);
         $conn->shouldReceive('del')->once()->with('key1', 'key2');
         $conn->shouldReceive('del')->once()->with('key3');
         $conn->shouldReceive('del')->once()->with('prefix:foo:forever_ref');
         $conn->shouldReceive('del')->once()->with('prefix:bar:forever_ref');
 
         // Standard tag keys
-        $conn->shouldReceive('smembers')->once()->with('prefix:foo:standard_ref')->andReturn(['key4', 'key5']);
-        $conn->shouldReceive('smembers')->once()->with('prefix:bar:standard_ref')->andReturn(['key6']);
+        $conn->shouldReceive('sscan')->once()->with('prefix:foo:standard_ref', '0', ['match' => '*', 'count' => 1000])->andReturn(['0', ['key4', 'key5']]);
+        $conn->shouldReceive('sscan')->once()->with('prefix:bar:standard_ref', '0', ['match' => '*', 'count' => 1000])->andReturn(['0', ['key6']]);
         $conn->shouldReceive('del')->once()->with('key4', 'key5');
         $conn->shouldReceive('del')->once()->with('key6');
         $conn->shouldReceive('del')->once()->with('prefix:foo:standard_ref');