Improve snap support

Connecting isn't necessary anymore
Only search when the query has something to search

libdiscover/backends/SnapBackend/SnapBackend.cpp

@@ -46,15 +46,6 @@ SnapBackend::SnapBackend(QObject* parent)
     , m_updater(new StandardBackendUpdater(this))
     , m_reviews(new SnapReviewsBackend(this))
 {
-    {
-        auto request = m_client.connect();
-        request->runSync();
-        m_valid = request->error() == QSnapdRequest::NoError;
-        if (!m_valid) {
-            qWarning() << "snap problem at initialize:" << request->errorString();
-            return;
-        }
-    }
     connect(m_reviews, &SnapReviewsBackend::ratingsReady, this, &AbstractResourcesBackend::emitRatingsReady);
 
     //make sure we populate the installed resources first
@@ -76,7 +67,7 @@ ResultsStream * SnapBackend::search(const AbstractResourcesBackend::Filters& fil
         return voidStream();
     } else if (filters.state >= AbstractResource::Installed) {
         return populate(m_client.list(), AbstractResource::Installed);
-    } else {
+    } else if (!filters.search.isEmpty()) {
         return populate(m_client.find(QSnapdClient::FindFlag::None, filters.search), AbstractResource::None);
     }
     return voidStream();
@@ -93,6 +84,7 @@ ResultsStream* SnapBackend::populate(T* job, AbstractResource::State state)
     auto stream = new ResultsStream(QStringLiteral("Snap-populate"));
 
     connect(job, &QSnapdFindRequest::complete, stream, [stream, this, state, job]() {
+        static_assert(std::is_base_of<QSnapdRequest, T>::value, "we can only populate QSnapdRequest");
         QSet<SnapResource*> higher = kFilter<QSet<SnapResource*>>(m_resources, [state](AbstractResource* res){ return res->state()>=state; });
 
         QVector<AbstractResource*> ret;

libdiscover/backends/SnapBackend/SnapBackend.h

@@ -43,7 +43,7 @@ public:
     int updatesCount() const override;
     AbstractBackendUpdater* backendUpdater() const override;
     AbstractReviewsBackend* reviewsBackend() const override;
-    bool isValid() const override { return m_valid; }
+    bool isValid() const override { return true; }
     QList<QAction*> messageActions() const override { return {}; }
 
     Transaction* installApplication(AbstractResource* app) override;
@@ -64,7 +64,6 @@ private:
     StandardBackendUpdater* m_updater;
     SnapReviewsBackend* m_reviews;
 
-    bool m_valid = true;
     bool m_fetching = false;
     QSnapdClient m_client;
 };