QSurfaceDataProxy: Fix crashes adding the first row of data

Adding one row causes an assert
ASSERT failure in QList::at: "index out of range", file include/QtCore/qlist.h, line 373
since there is no first row to check the column count against.
Check for empty as well.

Task-number: PYSIDE-1438
Change-Id: I225b87b764545b7a430472dc5a4b2e476a26a7ff
Reviewed-by: Tomi Korpipää <tomi.korpipaa@qt.io>
(cherry picked from commit 106bef0493758ddaeadd3b4d744227cb7feadb70)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 18 insertions, 4 deletions

diff --git a/src/datavisualization/data/qsurfacedataproxy.cpp b/src/datavisualization/data/qsurfacedataproxy.cpp
index 1252338e..bf66071b 100644
--- a/src/datavisualization/data/qsurfacedataproxy.cpp
+++ b/src/datavisualization/data/qsurfacedataproxy.cpp
@@ -475,7 +475,8 @@ void QSurfaceDataProxyPrivate::setItem(int rowIndex, int columnIndex, const QSur
 
 int QSurfaceDataProxyPrivate::addRow(QSurfaceDataRow *row)
 {
-    Q_ASSERT(m_dataArray->at(0)->size() == row->size());
+    Q_ASSERT(m_dataArray->isEmpty()
+             || m_dataArray->at(0)->size() == row->size());
     int currentSize = m_dataArray->size();
     m_dataArray->append(row);
     return currentSize;
@@ -485,7 +486,8 @@ int QSurfaceDataProxyPrivate::addRows(const QSurfaceDataArray &rows)
 {
     int currentSize = m_dataArray->size();
     for (int i = 0; i < rows.size(); i++) {
-        Q_ASSERT(m_dataArray->at(0)->size() == rows.at(i)->size());
+        Q_ASSERT(m_dataArray->isEmpty()
+                 || m_dataArray->at(0)->size() == rows.at(i)->size());
         m_dataArray->append(rows.at(i));
     }
     return currentSize;
@@ -494,7 +496,8 @@ int QSurfaceDataProxyPrivate::addRows(const QSurfaceDataArray &rows)
 void QSurfaceDataProxyPrivate::insertRow(int rowIndex, QSurfaceDataRow *row)
 {
     Q_ASSERT(rowIndex >= 0 && rowIndex <= m_dataArray->size());
-    Q_ASSERT(m_dataArray->at(0)->size() == row->size());
+    Q_ASSERT(m_dataArray->isEmpty()
+             || m_dataArray->at(0)->size() == row->size());
     m_dataArray->insert(rowIndex, row);
 }
 
@@ -503,7 +506,8 @@ void QSurfaceDataProxyPrivate::insertRows(int rowIndex, const QSurfaceDataArray
     Q_ASSERT(rowIndex >= 0 && rowIndex <= m_dataArray->size());
 
     for (int i = 0; i < rows.size(); i++) {
-        Q_ASSERT(m_dataArray->at(0)->size() == rows.at(i)->size());
+        Q_ASSERT(m_dataArray->isEmpty()
+                 || m_dataArray->at(0)->size() == rows.at(i)->size());
         m_dataArray->insert(rowIndex++, rows.at(i));
     }
 }
diff --git a/tests/auto/cpptest/q3dsurface-proxy/tst_proxy.cpp b/tests/auto/cpptest/q3dsurface-proxy/tst_proxy.cpp
index cda6bcce..1516e67d 100644
--- a/tests/auto/cpptest/q3dsurface-proxy/tst_proxy.cpp
+++ b/tests/auto/cpptest/q3dsurface-proxy/tst_proxy.cpp
@@ -47,6 +47,7 @@ private slots:
 
     void initialProperties();
     void initializeProperties();
+    void initialRow();
 
 private:
     QSurfaceDataProxy *m_proxy;
@@ -105,5 +106,14 @@ void tst_proxy::initializeProperties()
     QCOMPARE(m_proxy->rowCount(), 2);
 }
 
+void tst_proxy::initialRow()
+{
+    QSurfaceDataProxy proxy;
+    QSurfaceDataRow row{QSurfaceDataItem{QVector3D{0, 0, 0}},
+                        QSurfaceDataItem{QVector3D{1, 1, 1}}};
+    proxy.addRow(new QSurfaceDataRow(row));
+    proxy.addRow(new QSurfaceDataRow(row));
+}
+
 QTEST_MAIN(tst_proxy)
 #include "tst_proxy.moc"