Fix QHeaderView when the model is reset and section have moved.

The logicalIndices and visualIndices array where not clean of the
old sections, resulting in corrupted header.

Task-number: QTBUG-6058
Reviewed-by: Thierry

2 files changed, 65 insertions, 6 deletions

diff --git a/src/gui/itemviews/qheaderview.cpp b/src/gui/itemviews/qheaderview.cpp
index 5df8481..6f0fba6 100644
--- a/src/gui/itemviews/qheaderview.cpp
+++ b/src/gui/itemviews/qheaderview.cpp
@@ -1913,7 +1913,6 @@ void QHeaderView::initializeSections(int start, int end)
     Q_ASSERT(start >= 0);
     Q_ASSERT(end >= 0);
 
-    d->executePostedLayout();
     d->invalidateCachedSizeHint();
 
     if (end + 1 < d->sectionCount) {
@@ -1939,11 +1938,25 @@ void QHeaderView::initializeSections(int start, int end)
     d->sectionCount = end + 1;
 
     if (!d->logicalIndices.isEmpty()) {
-        d->logicalIndices.resize(d->sectionCount);
-        d->visualIndices.resize(d->sectionCount);
-        for (int i = start; i < d->sectionCount; ++i){
-            d->logicalIndices[i] = i;
-            d->visualIndices[i] = i;
+        if (oldCount <= d->sectionCount) {
+            d->logicalIndices.resize(d->sectionCount);
+            d->visualIndices.resize(d->sectionCount);
+            for (int i = oldCount; i < d->sectionCount; ++i) {
+                d->logicalIndices[i] = i;
+                d->visualIndices[i] = i;
+            }
+        } else {
+            int j = 0;
+            for (int i = 0; i < oldCount; ++i) {
+                int v = d->logicalIndices.at(i);
+                if (v < d->sectionCount) {
+                    d->logicalIndices[j] = v;
+                    d->visualIndices[v] = j;
+                    j++;
+                }
+            }
+            d->logicalIndices.resize(d->sectionCount);
+            d->visualIndices.resize(d->sectionCount);
         }
     }
 
diff --git a/tests/auto/qheaderview/tst_qheaderview.cpp b/tests/auto/qheaderview/tst_qheaderview.cpp
index c13e829..a8e7461 100644
--- a/tests/auto/qheaderview/tst_qheaderview.cpp
+++ b/tests/auto/qheaderview/tst_qheaderview.cpp
@@ -43,6 +43,7 @@
 #include <QtTest/QtTest>
 #include <QStandardItemModel>
 #include <QStringListModel>
+#include <QSortFilterProxyModel>
 
 #include <qabstractitemmodel.h>
 #include <qapplication.h>
@@ -188,6 +189,7 @@ private slots:
     void task236450_hidden_data();
     void task236450_hidden();
     void task248050_hideRow();
+    void QTBUG6058_reset();
 
 protected:
     QHeaderView *view;
@@ -1947,5 +1949,49 @@ void tst_QHeaderView::task248050_hideRow()
 }
 
 
+//returns 0 if everything is fine.
+static int checkHeaderViewOrder(QHeaderView *view, const QVector<int> &expected)
+{
+    if (view->count() != expected.count())
+        return 1;
+
+    for (int i = 0; i < expected.count(); i++) {
+        if (view->logicalIndex(i) != expected.at(i))
+            return i + 10;
+        if (view->visualIndex(expected.at(i)) != i)
+            return i + 100;
+    }
+    return 0;
+}
+
+
+void tst_QHeaderView::QTBUG6058_reset()
+{
+    QStringListModel model1( QStringList() << "0" << "1" << "2" << "3" << "4" << "5" );
+    QStringListModel model2( QStringList() << "a" << "b" << "c" );
+    QSortFilterProxyModel proxy;
+
+    QHeaderView view(Qt::Vertical);
+    view.setModel(&proxy);
+    view.show();
+    QTest::qWait(20);
+
+    proxy.setSourceModel(&model1);
+    QApplication::processEvents();
+    view.swapSections(0,2);
+    view.swapSections(1,4);
+    QApplication::processEvents();
+    QCOMPARE(checkHeaderViewOrder(&view, QVector<int>() << 2 << 4 << 0 << 3 << 1 << 5) , 0);
+
+    proxy.setSourceModel(&model2);
+    QApplication::processEvents();
+    QCOMPARE(checkHeaderViewOrder(&view, QVector<int>() << 2 << 0 << 1 ) , 0);
+
+    proxy.setSourceModel(&model1);
+    QApplication::processEvents();
+    QCOMPARE(checkHeaderViewOrder(&view, QVector<int>() << 2 << 0 << 1 << 3 << 4 << 5 ) , 0);
+}
+
+
 QTEST_MAIN(tst_QHeaderView)
 #include "tst_qheaderview.moc"