2 files changed, 47 insertions, 2 deletions

diff --git a/src/gui/itemviews/qtableview.cpp b/src/gui/itemviews/qtableview.cpp
index c80faa2..02e5fff 100644
--- a/src/gui/itemviews/qtableview.cpp
+++ b/src/gui/itemviews/qtableview.cpp
@@ -117,7 +117,7 @@ void QSpanCollection::updateSpan(QSpanCollection::Span *span, int old_height)
         Index::iterator it_y = index.lowerBound(-span->bottom());
         Q_ASSERT(it_y != index.end()); //it_y must exist since the span is in the list
         while (-it_y.key() <= span->top() + old_height -1) {
-            if(-it_y.key() != span->bottom()) {
+            if (-it_y.key() > span->bottom()) {
                 (*it_y).remove(-span->left());
                 if (it_y->isEmpty()) {
                     it_y = index.erase(it_y) - 1;
@@ -544,6 +544,47 @@ void QSpanCollection::updateRemovedColumns(int start, int end)
     qDeleteAll(toBeDeleted);
 }
 
+#ifdef QT_BUILD_INTERNAL
+/*!
+  \internal
+  Checks whether the span index structure is self-consistent, and consistent with the spans list.
+*/
+bool QSpanCollection::checkConsistency() const
+{
+    for (Index::const_iterator it_y = index.begin(); it_y != index.end(); ++it_y) {
+        int y = -it_y.key();
+        const SubIndex &subIndex = it_y.value();
+        for (SubIndex::const_iterator it = subIndex.begin(); it != subIndex.end(); ++it) {
+            int x = -it.key();
+            Span *span = it.value();
+            if (!spans.contains(span) || span->left() != x
+                || y < span->top() || y > span->bottom())
+                return false;
+        }
+    }
+
+    foreach (const Span *span, spans) {
+        if (span->width() < 1 || span->height() < 1
+            || (span->width() == 1 && span->height() == 1))
+            return false;
+        for (int y = span->top(); y <= span->bottom(); ++y) {
+            Index::const_iterator it_y = index.find(-y);
+            if (it_y == index.end()) {
+                if (y == span->top())
+                    return false;
+                else
+                    continue;
+            }
+            const SubIndex &subIndex = it_y.value();
+            SubIndex::const_iterator it = subIndex.find(-span->left());
+            if (it == subIndex.end() || it.value() != span)
+                return false;
+        }
+    }
+    return true;
+}
+#endif
+
 class QTableCornerButton : public QAbstractButton
 {
     Q_OBJECT
diff --git a/src/gui/itemviews/qtableview_p.h b/src/gui/itemviews/qtableview_p.h
index 9fa14c2..6b19ded 100644
--- a/src/gui/itemviews/qtableview_p.h
+++ b/src/gui/itemviews/qtableview_p.h
@@ -74,7 +74,7 @@ QT_BEGIN_NAMESPACE
 * The key of the first map is the row where the subspan starts, the value of the first map is
 * a list (map) of all subspans that starts at the same row.  It is indexed with its row
 */
-class QSpanCollection
+class Q_AUTOTEST_EXPORT QSpanCollection
 {
 public:
     struct Span
@@ -112,6 +112,10 @@ public:
     void updateRemovedRows(int start, int end);
     void updateRemovedColumns(int start, int end);
 
+#ifdef QT_BUILD_INTERNAL
+    bool checkConsistency() const;
+#endif
+
     typedef QLinkedList<Span *> SpanList;
     SpanList spans; //lists of all spans
 private: