Bugfix: Validate tags on cache hit

src/Spiritix/LadaCache/Cache.php

@@ -91,6 +91,23 @@ public function set($key, array $tags, $data)
         }
     }
 
+    /**
+     * Store given key in tags.
+     *
+     * Ensure key exists in the given tags.
+     * Redis sets are unique, so the same value will not be added twice.
+     *
+     * @param string $key
+     * @param array $tags
+     */
+    public function setCacheTagsForKey($key, array $tags)
+    {
+        $key = $this->redis->prefix($key);
+        foreach ($tags as $tag) {
+            $this->redis->sadd($this->redis->prefix($tag), $key);
+        }
+    }
+
     /**
      * Returns value of a cached key.
      *

src/Spiritix/LadaCache/QueryHandler.php

@@ -154,10 +154,13 @@ public function cacheQuery($queryClosure)
 
         $action = ($result === null) ? 'Miss' : 'Hit';
 
-        // If not, execute the query closure and cache the result
         if ($result === null) {
+            // Cache miss, execute the query closure and cache the result
             $result = $queryClosure();
             $this->cache->set($key, $tags, $result);
+        } else {
+            // Cache hit, validate cache tags on key
+            $this->cache->setCacheTagsForKey($key, $tags);
         }
 
         $this->destructCollector($reflector, $tags, $key, $action);

tests/InvalidatorTest.php

@@ -91,4 +91,24 @@ public function testCacheStateWhenInvalideIsCalledInDistributedSystem(): void
         $this->assertTrue($this->cache->has('key3'));
         $this->assertTrue($this->cache->has('tag2'));
     }
+
+    public function testCacheHitsValidateKeyInTags(): void
+    {
+        $this->cache->set('key1', ['tag2'], 'data'); // <-- Bug, simulate 'tag1' missing from key1
+        $this->cache->set('key2', ['tag1', 'tag2'], 'data');
+
+        // Simulate cache hit on Key1
+        // Start --------------------------------------------------------------------------------
+        $data = $this->cache->get('key1');
+        $this->assertSame('data', $data);
+        $this->cache->setCacheTagsForKey('key1', ['tag1', 'tag2']); // <-- Validate tags for key
+        // End ----------------------------------------------------------------------------------
+
+        // Invalidate cache.
+        $this->invalidator->invalidate(['tag1']);
+
+        // Check cache is invalidated:
+        $this->assertFalse($this->cache->has('key1'));
+        $this->assertFalse($this->cache->has('key2'));
+    }
 }