Fix folder tree crash during git checkout

liteidex/src/utils/folderview/multiindexmodel.cpp

@@ -123,7 +123,14 @@ QModelIndexPairList MultiIndexModelPrivate::store_persistent_indexes(const QMode
     QModelIndexPairList source_indexes;
     foreach (QModelIndex proxy_index, persistentList) {
         SourceModelIndex index = q->mapToSourceEx(proxy_index);
-        source_indexes.append(qMakePair(proxy_index, QPersistentModelIndex(index.index)));
+        // A source model may be rebuilding its index tree while emitting a
+        // layout change. Keep invalid mappings invalid instead of asking it
+        // to create an index from stale mapping data.
+        if (index.model == 0 || !index.index.isValid()) {
+            source_indexes.append(qMakePair(proxy_index, QPersistentModelIndex()));
+        } else {
+            source_indexes.append(qMakePair(proxy_index, QPersistentModelIndex(index.index)));
+        }
     }
     return source_indexes;
 }
@@ -499,11 +506,18 @@ SourceModelIndex MultiIndexModel::mapToSourceEx(const QModelIndex &proxyIndex) c
 
     Mapping *m = (Mapping*)proxyIndex.internalPointer();
     if (m == 0) {
+        if (proxyIndex.row() < 0 || proxyIndex.row() >= d->indexList.size()) {
+            return SourceModelIndex();
+        }
         SourceModelIndex si = d->indexList[proxyIndex.row()];
+        if (si.model == 0 || !si.index.isValid()) {
+            return SourceModelIndex();
+        }
         si.index = si.index.sibling(si.index.row(),proxyIndex.column());
         return si;
     }
-    if (m->source_rows.size() <= proxyIndex.row()) {
+    if (m->sourceModel == 0 || proxyIndex.row() < 0 ||
+        m->source_rows.size() <= proxyIndex.row()) {
         return SourceModelIndex();
     }
 
@@ -937,14 +951,13 @@ void MultiIndexModelPrivate::_q_sourceLayoutAboutToBeChanged()
 //    q->layoutAboutToBeChanged();
     Q_Q(MultiIndexModel);
     saved_persistent_indexes.clear();
-    emit q->layoutAboutToBeChanged();
     QModelIndexList persistentList = q->persistentIndexList();
-    if (persistentList.isEmpty())
-        return;
+    if (!persistentList.isEmpty())
+        saved_persistent_indexes = store_persistent_indexes(persistentList);
 
-//    QAbstractItemModel *model = (QAbstractItemModel*)sender();
-//    qDebug() << "begin changed" << model;
-    saved_persistent_indexes = store_persistent_indexes(persistentList);
+    // Save indexes before notifying observers. Views may synchronously query
+    // the proxy while the source model is in its layout-about-to-change phase.
+    emit q->layoutAboutToBeChanged();
 }
 
 void MultiIndexModelPrivate::_q_sourceLayoutChanged()

liteidex/src/utils/folderview/multiindexmodel_p.h

@@ -38,7 +38,7 @@ struct Mapping
     int          rowCount;
     QVector<int> source_rows;      //source rows
     QVector<int> proxy_rows;       //proxy rows
-    QModelIndex  sourceParent;    //source parent
+    QPersistentModelIndex sourceParent; //source parent
     QAbstractItemModel *sourceModel;
 };
 
@@ -118,4 +118,3 @@ public slots:
 };
 
 #endif // MULTIINDEXMODEL_P_H
-