Add workaround to show torrent's error when all its trackers have err…

…ors (#462)

CHANGELOG.md

@@ -15,9 +15,10 @@
   - Minimum cxxopts version is 3.1.1
   - Minimum gettext version is 0.21
 - Removed dependency on Qt Concurrent module
-- Notification portal is used for notification in Flatpak
 - Breeze is used as a fallback icon theme and should be installed as a runtime dependency
 - Clarified runtime dependency on Qt's SVG image format plugin
+- Notification portal is used for notification in Flatpak
+- Added workaround for Transmission not showing an error for torrent when all trackers have failed
 - Networking and some other async code is rewritten using C++ coroutines. Hopefully nothing is broken :)
 
 ### Fixed

src/rpc/torrent.cpp

@@ -247,6 +247,7 @@ namespace tremotesf {
                 updateProperty(*key, i.value(), changed, firstTime, rpc);
             }
         }
+        applyTrackerErrorWorkaround(changed);
         return changed;
     }
 
@@ -264,6 +265,7 @@ namespace tremotesf {
                 updateProperty(*key, values[static_cast<QJsonArray::size_type>(i)], changed, firstTime, rpc);
             }
         }
+        applyTrackerErrorWorkaround(changed);
         return changed;
     }
 
@@ -450,6 +452,24 @@ namespace tremotesf {
         throw std::logic_error(fmt::format("Can't update key {}", static_cast<int>(intKey)));
     }
 
+    void TorrentData::applyTrackerErrorWorkaround(bool& changed) {
+        // Sometimes Transmission doesn't propagate tracker error to the torrent's status
+        if (error != Error::None) {
+            return;
+        }
+        if (trackers.empty()) {
+            return;
+        }
+        // Only set error if *all* trackers have an error
+        if (std::ranges::any_of(trackers, [](const Tracker& tracker) { return tracker.errorMessage().isEmpty(); })) {
+            return;
+        }
+        // Set error from first tracker
+        error = Error::TrackerError;
+        errorString = trackers.front().errorMessage();
+        changed = true;
+    }
+
     Torrent::Torrent(int id, const QJsonObject& object, Rpc* rpc, QObject* parent) : QObject(parent), mRpc(rpc) {
         mData.id = id;
         [[maybe_unused]] const bool changed = mData.update(object, true, rpc);

src/rpc/torrent.h

@@ -131,6 +131,7 @@ namespace tremotesf {
         void updateProperty(
             TorrentData::UpdateKey key, const QJsonValue& value, bool& changed, bool firstTime, const Rpc* rpc
         );
+        void applyTrackerErrorWorkaround(bool& changed);
     };
 
     class Torrent final : public QObject {

src/rpc/tracker.h

@@ -37,7 +37,7 @@ namespace tremotesf {
         int tier() const { return mTier; }
 
         Status status() const { return mStatus; };
-        QString errorMessage() const { return mErrorMessage; };
+        const QString& errorMessage() const { return mErrorMessage; };
 
         int peers() const { return mPeers; };
         int seeders() const { return mSeeders; }