Fix segfault when trying to remove a non-subscribed podcast

BUG: 471107

src/datamanager.cpp

@@ -207,14 +207,19 @@ void DataManager::removeFeed(const int index)
 {
     // Get feed pointer
     Feed *feed = getFeed(m_feedmap[index]);
+    if (feed) {
         removeFeed(feed);
+    }
 }
 
 void DataManager::removeFeeds(const QStringList &feedurls)
 {
     QList<Feed *> feeds;
     for (QString feedurl : feedurls) {
-        feeds << getFeed(feedurl);
+        Feed *feed = getFeed(feedurl);
+        if (feed) {
+            feeds << feed;
+        }
     }
     removeFeeds(feeds);
 }
@@ -224,15 +229,18 @@ void DataManager::removeFeeds(const QVariantList feedVariantList)
     QList<Feed *> feeds;
     for (QVariant feedVariant : feedVariantList) {
         if (feedVariant.canConvert<Feed *>()) {
+            if (feedVariant.value<Feed *>()) {
                 feeds << feedVariant.value<Feed *>();
             }
         }
+    }
     removeFeeds(feeds);
 }
 
 void DataManager::removeFeeds(const QList<Feed *> &feeds)
 {
     for (Feed *feed : feeds) {
+        if (feed) {
             const QString feedurl = feed->url();
             int index = m_feedmap.indexOf(feedurl);
 
@@ -311,6 +319,7 @@ void DataManager::removeFeeds(const QList<Feed *> &feeds)
 
             Q_EMIT feedRemoved(index);
         }
+    }
 
     // if settings allow, then upload these changes immediately to sync server
     Sync::instance().doQuickSync();