QTreeView: fix drawing branches of model that adds or remove rows dynamically

The lasts commits in the treeview did put the flags weither
item has child or is the last in cache in the viewItem vector.
But the cache was not updated while the model is modified.

Reviewed-by: Thierry

3 files changed, 138 insertions, 4 deletions

diff --git a/src/gui/itemviews/qtreeview.cpp b/src/gui/itemviews/qtreeview.cpp
index be64c46..3856293 100644
--- a/src/gui/itemviews/qtreeview.cpp
+++ b/src/gui/itemviews/qtreeview.cpp
@@ -2434,7 +2434,9 @@ void QTreeView::rowsInserted(const QModelIndex &parent, int start, int end)
         return;
     }
 
-    if (parent != d->root && !d->isIndexExpanded(parent) && d->model->rowCount(parent) > (end - start) + 1) {
+    const int parentRowCount = d->model->rowCount(parent);
+    const int delta = end - start + 1;
+    if (parent != d->root && !d->isIndexExpanded(parent) && parentRowCount > delta) {
         QAbstractItemView::rowsInserted(parent, start, end);
         return;
     }
@@ -2449,11 +2451,29 @@ void QTreeView::rowsInserted(const QModelIndex &parent, int start, int end)
                                                     ? d->viewItems.count()
                                                     : d->viewItems.at(parentItem).total) - 1;
 
-        const int delta = end - start + 1;
+        if (parentRowCount == end + 1 && start > 0) {
+            //need to Update hasMoreSiblings
+            int previousRow = start - 1;
+            QModelIndex previousSibilingModelIndex = d->model->index(previousRow, 0, parent);
+            bool isHidden = d->isRowHidden(previousSibilingModelIndex);
+            while (isHidden && previousRow > 0) {
+                previousRow--;
+                previousSibilingModelIndex = d->model->index(previousRow, 0, parent);
+                isHidden = d->isRowHidden(previousSibilingModelIndex);
+            }
+            if (!isHidden) {
+                const int previousSibilling = d->viewIndex(previousSibilingModelIndex);
+                if(previousSibilling != -1)
+                    d->viewItems[previousSibilling].hasMoreSiblings = true;
+            }
+        }
+
         QVector<QTreeViewItem> insertedItems(delta);
         for (int i = 0; i < delta; ++i) {
             insertedItems[i].index = d->model->index(i + start, 0, parent);
             insertedItems[i].level = childLevel;
+            insertedItems[i].hasChildren = d->hasVisibleChildren(insertedItems[i].index);
+            insertedItems[i].hasMoreSiblings = !((i == delta - 1) && (parentRowCount == end +1));
         }
         if (d->viewItems.isEmpty())
             d->defaultItemHeight = indexRowSizeHint(insertedItems[0].index);
@@ -2495,13 +2515,17 @@ void QTreeView::rowsInserted(const QModelIndex &parent, int start, int end)
                   d->viewItems.begin() + insertPos + 1);
         }
 
+        if (parentItem != -1)
+            d->viewItems[parentItem].hasChildren = true;
         d->updateChildCount(parentItem, delta);
+
         updateGeometries();
         viewport()->update();
     } else if ((parentItem != -1) && d->viewItems.at(parentItem).expanded) {
         d->doDelayedItemsLayout();
     } else if (parentItem != -1 && (d->model->rowCount(parent) == end - start + 1)) {
-        // the parent just went from 0 children to having some update to re-paint the decoration
+        // the parent just went from 0 children to more. update to re-paint the decoration
+        d->viewItems[parentItem].hasChildren = true;
         viewport()->update();
     }
     QAbstractItemView::rowsInserted(parent, start, end);
@@ -3706,6 +3730,7 @@ void QTreeViewPrivate::rowsRemoved(const QModelIndex &parent,
 
         const int delta = end - start + 1;
 
+        int previousSibiling = -1;
         int removedCount = 0;
         for (int item = firstChildItem; item <= lastChildItem; ) {
             Q_ASSERT(viewItems.at(item).level == childLevel);
@@ -3713,6 +3738,7 @@ void QTreeViewPrivate::rowsRemoved(const QModelIndex &parent,
             //Q_ASSERT(modelIndex.parent() == parent);
             const int count = viewItems.at(item).total + 1;
             if (modelIndex.row() < start) {
+                previousSibiling = item;
                 // not affected by the removal
                 item += count;
             } else if (modelIndex.row() <= end) {
@@ -3730,7 +3756,13 @@ void QTreeViewPrivate::rowsRemoved(const QModelIndex &parent,
             }
         }
 
+        if (previousSibiling != -1 && after && model->rowCount(parent) == start)
+            viewItems[previousSibiling].hasMoreSiblings = false;
+
+
         updateChildCount(parentItem, -removedCount);
+        if (parentItem != -1 && viewItems.at(parentItem).total == 0)
+            viewItems[parentItem].hasChildren = false; //every children have been removed;
         if (after) {
             q->updateGeometries();
             viewport->update();
diff --git a/src/gui/itemviews/qtreeview_p.h b/src/gui/itemviews/qtreeview_p.h
index 62676d8..aad5837 100644
--- a/src/gui/itemviews/qtreeview_p.h
+++ b/src/gui/itemviews/qtreeview_p.h
@@ -62,7 +62,8 @@ QT_BEGIN_NAMESPACE
 
 struct QTreeViewItem
 {
-    QTreeViewItem() : expanded(false), spanning(false), total(0), level(0), height(0) {}
+    QTreeViewItem() : expanded(false), spanning(false), hasChildren(false),
+                      hasMoreSiblings(false), total(0), level(0), height(0) {}
     QModelIndex index; // we remove items whenever the indexes are invalidated
     uint expanded : 1;
     uint spanning : 1;
diff --git a/tests/auto/qtreeview/tst_qtreeview.cpp b/tests/auto/qtreeview/tst_qtreeview.cpp
index 75c02e9..90e6c5c 100644
--- a/tests/auto/qtreeview/tst_qtreeview.cpp
+++ b/tests/auto/qtreeview/tst_qtreeview.cpp
@@ -2892,6 +2892,8 @@ void tst_QTreeView::styleOptionViewItem()
 
                 QVERIFY(!opt.text.isEmpty());
                 QCOMPARE(opt.index, index);
+                //qDebug() << index << opt.text;
+
                 if (allCollapsed)
                     QCOMPARE(!(opt.features & QStyleOptionViewItemV2::Alternate), !(index.row() % 2));
                 QCOMPARE(!(opt.features & QStyleOptionViewItemV2::HasCheckIndicator), !opt.text.contains("Checkable"));
@@ -2979,9 +2981,108 @@ void tst_QTreeView::styleOptionViewItem()
     view.expandAll();
     QApplication::processEvents();
     QTRY_VERIFY(delegate.count >= 13);
+    delegate.count = 0;
     view.collapse(par2->index());
     QApplication::processEvents();
     QTRY_VERIFY(delegate.count >= 4);
+
+
+    //test dynamic models
+    {
+        delegate.count = 0;
+        QStandardItemModel model2;
+        QStandardItem *item0 = new QStandardItem("OnlyOne Last");
+        model2.appendRow(QList<QStandardItem*>() << item0);
+        view.setModel(&model2);
+        QApplication::processEvents();
+        QTRY_VERIFY(delegate.count >= 1);
+        QApplication::processEvents();
+
+        QStandardItem *item00 = new QStandardItem("OnlyOne Last");
+        item0->appendRow(QList<QStandardItem*>() << item00);
+        item0->setText("OnlyOne Last HasChildren");
+        QApplication::processEvents();
+        delegate.count = 0;
+        view.expandAll();
+        QApplication::processEvents();
+        QTRY_VERIFY(delegate.count >= 2);
+        QApplication::processEvents();
+
+        QStandardItem *item1 = new QStandardItem("OnlyOne Last");
+        delegate.count = 0;
+        item0->setText("OnlyOne HasChildren");
+        model2.appendRow(QList<QStandardItem*>() << item1);
+        QApplication::processEvents();
+        QTRY_VERIFY(delegate.count >= 3);
+        QApplication::processEvents();
+
+        QStandardItem *item01 = new QStandardItem("OnlyOne Last");
+        delegate.count = 0;
+        item00->setText("OnlyOne");
+        item0->appendRow(QList<QStandardItem*>() << item01);
+        QApplication::processEvents();
+        QTRY_VERIFY(delegate.count >= 4);
+        QApplication::processEvents();
+
+        QStandardItem *item000 = new QStandardItem("OnlyOne Last");
+        delegate.count = 0;
+        item00->setText("OnlyOne HasChildren");
+        item00->appendRow(QList<QStandardItem*>() << item000);
+        QApplication::processEvents();
+        QTRY_VERIFY(delegate.count >= 5);
+        QApplication::processEvents();
+
+        delegate.count = 0;
+        item0->removeRow(0);
+        QApplication::processEvents();
+        QTRY_VERIFY(delegate.count >= 3);
+        QApplication::processEvents();
+
+        item00 = new QStandardItem("OnlyOne");
+        item0->insertRow(0, QList<QStandardItem*>() << item00);
+        QApplication::processEvents();
+        delegate.count = 0;
+        view.expandAll();
+        QApplication::processEvents();
+        QTRY_VERIFY(delegate.count >= 4);
+        QApplication::processEvents();
+
+        delegate.count = 0;
+        item0->removeRow(1);
+        item00->setText("OnlyOne Last");
+        QApplication::processEvents();
+        QTRY_VERIFY(delegate.count >= 3);
+        QApplication::processEvents();
+
+        delegate.count = 0;
+        item0->removeRow(0);
+        item0->setText("OnlyOne");
+        QApplication::processEvents();
+        QTRY_VERIFY(delegate.count >= 2);
+        QApplication::processEvents();
+
+        //with hidden items
+        item0->setText("OnlyOne HasChildren");
+        item00 = new QStandardItem("OnlyOne");
+        item0->appendRow(QList<QStandardItem*>() << item00);
+        item01 = new QStandardItem("Assert");
+        item0->appendRow(QList<QStandardItem*>() << item01);
+        view.setRowHidden(1, item0->index(), true);
+        view.expandAll();
+        QStandardItem *item02 = new QStandardItem("OnlyOne Last");
+        item0->appendRow(QList<QStandardItem*>() << item02);
+        delegate.count = 0;
+        QApplication::processEvents();
+        QTRY_VERIFY(delegate.count >= 4);
+        QApplication::processEvents();
+
+        item0->removeRow(2);
+        item00->setText("OnlyOne Last");
+        delegate.count = 0;
+        QApplication::processEvents();
+        QTRY_VERIFY(delegate.count >= 3);
+        QApplication::processEvents();
+    }
 }
 
 class task174627_TreeView : public QTreeView