Pull request: 5190-fix-panic

Updates AdguardTeam/AdGuardHome#4695.
Updates AdguardTeam/AdGuardHome#5190.

Squashed commit of the following:

commit 881fbc0
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Dec 2 15:28:47 2022 +0300

    proxy: fix panic

proxy/cache.go

@@ -318,15 +318,19 @@ func (c *cache) clearItems() {
 	c.itemsLock.Lock()
 	defer c.itemsLock.Unlock()
 
-	c.items.Clear()
+	if c.items != nil {
+		c.items.Clear()
+	}
 }
 
 // clearItemsWithSubnet empties the subnet cache.
 func (c *cache) clearItemsWithSubnet() {
 	c.itemsWithSubnetLock.Lock()
 	defer c.itemsWithSubnetLock.Unlock()
 
-	c.itemsWithSubnet.Clear()
+	if c.itemsWithSubnet != nil {
+		c.itemsWithSubnet.Clear()
+	}
 }
 
 // cacheTTL returns the number of seconds for which m is valid to be cached.

proxy/cache_test.go

@@ -146,8 +146,8 @@ func TestCache_expired(t *testing.T) {
 			key := msgToKey(reply)
 			data := (&cacheItem{
 				m:   reply,
-				ttl: tc.ttl,
 				u:   testUpsAddr,
+				ttl: tc.ttl,
 			}).pack()
 			testCache.items.Set(key, data)
 			t.Cleanup(testCache.items.Clear)