Fix crashes in expand clip.

Related to #300

src/jobs/cachejob.cpp

@@ -49,8 +49,6 @@ CacheJob::CacheJob(const QString &binId, int thumbsCount, int inPoint, int outPo
         m_fullWidth ++;
     }
     m_imageHeight += m_imageHeight % 2;
-    auto item = pCore->projectItemModel()->getItemByBinId(binId);
-    Q_ASSERT(item != nullptr && item->itemType() == AbstractProjectItem::ClipItem);
     connect(this, &CacheJob::jobCanceled, [&] () {
         m_done = true;
         m_clipId.clear();

src/timeline2/model/timelinefunctions.cpp

@@ -1319,6 +1319,11 @@ bool TimelineFunctions::pasteClips(const std::shared_ptr<TimelineItemModel> &tim
         }
         videoTracks << atrackPos;
     }
+    if (audioTracks.isEmpty() && videoTracks.isEmpty()) {
+        // playlist does not have any tracks, exit
+        semaphore.release(1);
+        return true;
+    }
     // Now we have a list of all source tracks, check that we have enough target tracks
     std::sort(videoTracks.begin(), videoTracks.end());
     std::sort(audioTracks.begin(), audioTracks.end());

src/timeline2/view/timelinecontroller.cpp

@@ -2989,22 +2989,24 @@ void TimelineController::expandActiveClip()
         if (m_model->isGroup(i)) {
             std::unordered_set<int> children = m_model->m_groups->getLeaves(i);
             items_list.insert(children.begin(), children.end());
-            m_model->requestClipUngroup(i, undo, redo);
         } else {
             items_list.insert(i);
         }
     }
+    m_model->requestClearSelection();
     bool result = true;
     int processed = 0;
     for (int id : items_list) {
-        /*if (mainId == -1 && m_model->getItemTrackId(id) == m_activeTrack) {
-            mainId = id;
-            continue;
-        }*/
         if (result && m_model->isClip(id)) {
             std::shared_ptr<ClipModel> clip = m_model->getClipPtr(id);
             if (clip->clipType() == ClipType::Playlist) {
                 int pos = clip->getPosition();
+                if (m_model->m_groups->isInGroup(id)) {
+                    int targetRoot = m_model->m_groups->getRootId(id);
+                    if (m_model->isGroup(targetRoot)) {
+                        m_model->requestClipUngroup(targetRoot, undo, redo);
+                    }
+                }
                 QDomDocument doc = TimelineFunctions::extractClip(m_model, id, getClipBinId(id));
                 m_model->requestClipDeletion(id, undo, redo);
                 result = TimelineFunctions::pasteClips(m_model, doc.toString(), m_activeTrack, pos, undo, redo);