Let ReverseResolution always return/emit a result

src/base/net/reverseresolution.cpp

@@ -59,14 +59,8 @@ ReverseResolution::~ReverseResolution()
 
 void ReverseResolution::resolve(const QHostAddress &ip)
 {
-    if (ip.isNull())
-        return;
-
     const QString *hostname = m_cache.object(ip);
     if (hostname) {
-        if (hostname->isEmpty())
-            ;  // resolution didn't get meaningful results, so do nothing
-        else
         emit ipResolved(ip, *hostname);
         return;
     }
@@ -80,15 +74,14 @@ void ReverseResolution::hostResolved(const QHostInfo &host)
 {
     const QHostAddress ip = m_lookups.take(host.lookupId());
 
-    if (host.error() != QHostInfo::NoError)
+    if (host.error() != QHostInfo::NoError) {
+        emit ipResolved(ip, {});
         return;
+    }
 
-    const QString hostname = host.hostName();
+    const QString hostname = isUsefulHostName(host.hostName(), ip)
-    if (isUsefulHostName(hostname, ip)) {
+        ? host.hostName()
+        : QString();
     m_cache.insert(ip, new QString(hostname));
     emit ipResolved(ip, hostname);
 }
-    else {
-        m_cache.insert(ip, new QString());
-    }
-}

src/gui/properties/peerlistwidget.cpp

@@ -428,6 +428,9 @@ void PeerListWidget::updatePeer(const BitTorrent::TorrentHandle *torrent, const
 
 void PeerListWidget::handleResolved(const QHostAddress &ip, const QString &hostname) const
 {
+    if (hostname.isEmpty())
+        return;
+
     const QSet<QStandardItem *> items = m_itemsByIP.value(ip);
     for (QStandardItem *item : items)
         item->setData(hostname, Qt::DisplayRole);