Fix crash on group move. Related to #435

src/timeline2/model/timelinemodel.cpp

@@ -1407,7 +1407,7 @@ bool TimelineModel::requestGroupMove(int itemId, int groupId, int delta_track, i
 
     // Sort clips first
     std::vector<int> sorted_clips(all_clips.begin(), all_clips.end());
-    std::sort(sorted_clips.begin(), sorted_clips.end(), [this, delta_pos](int clipId1, int clipId2) {
+    std::sort(sorted_clips.begin(), sorted_clips.end(), [this, delta_pos](const int clipId1, const int clipId2) {
         int p1 = m_allClips[clipId1]->getPosition();
         int p2 = m_allClips[clipId2]->getPosition();
         return delta_pos > 0 ? p2 <= p1 : p1 <= p2;
@@ -1415,7 +1415,7 @@ bool TimelineModel::requestGroupMove(int itemId, int groupId, int delta_track, i
 
     // Sort compositions. We need to delete in the move direction from top to bottom
     std::vector<int> sorted_compositions(all_compositions.begin(), all_compositions.end());
-    std::sort(sorted_compositions.begin(), sorted_compositions.end(), [this, delta_track, delta_pos](int clipId1, int clipId2) {
+    std::sort(sorted_compositions.begin(), sorted_compositions.end(), [this, delta_track, delta_pos](const int clipId1, const int clipId2) {
         int p1 = delta_track < 0
                      ? getTrackMltIndex(m_allCompositions[clipId1]->getCurrentTrackId())
                      : delta_track > 0 ? -getTrackMltIndex(m_allCompositions[clipId1]->getCurrentTrackId()) : m_allCompositions[clipId1]->getPosition();

src/timeline2/view/timelinecontroller.cpp

@@ -1104,12 +1104,16 @@ void TimelineController::cutClipUnderCursor(int position, int track)
 
 int TimelineController::requestSpacerStartOperation(int trackId, int position)
 {
-    return TimelineFunctions::requestSpacerStartOperation(m_model, trackId, position);
+    QMutexLocker lk(&m_metaMutex);
+    int itemId = TimelineFunctions::requestSpacerStartOperation(m_model, trackId, position);
+    return itemId;
 }
 
 bool TimelineController::requestSpacerEndOperation(int clipId, int startPosition, int endPosition)
 {
-    return TimelineFunctions::requestSpacerEndOperation(m_model, clipId, startPosition, endPosition);
+    QMutexLocker lk(&m_metaMutex);
+    bool result = TimelineFunctions::requestSpacerEndOperation(m_model, clipId, startPosition, endPosition);
+    return result;
 }
 
 void TimelineController::seekCurrentClip(bool seekToEnd)
@@ -2387,7 +2391,7 @@ bool TimelineController::endFakeGroupMove(int clipId, int groupId, int delta_tra
 
     // Sort clips. We need to delete from right to left to avoid confusing the view
     std::vector<int> sorted_clips(all_items.begin(), all_items.end());
-    std::sort(sorted_clips.begin(), sorted_clips.end(), [this](int clipId1, int clipId2) {
+    std::sort(sorted_clips.begin(), sorted_clips.end(), [this](const int clipId1, const int clipId2) {
         int p1 = m_model->isClip(clipId1) ? m_model->m_allClips[clipId1]->getPosition() : m_model->m_allCompositions[clipId1]->getPosition();
         int p2 = m_model->isClip(clipId2) ? m_model->m_allClips[clipId2]->getPosition() : m_model->m_allCompositions[clipId2]->getPosition();
         return p2 <= p1;