QHeaderView - length returns wrong value fix

setSectionHidden called with (logindex, true) will
sometimes not do a (correct) call to
resizeSection(logicalIndex, 0) at once.

However it does execute d->doDelayedResizeSections().
Therefore the section is going to be hidden later.

However it is a problem that the length meanwhile is wrong.
(That is a value that is not the sum of the sections)

This is fixed by execute updates before returning the
length.

This is a backport of SHA 125016ad241125176e5bebab94eebcf50fac20bc

Task-number: QTBUG-14242

Change-Id: Ia1d2f6db3213792b250a6a37942b56554261cd3a
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>

2 files changed, 20 insertions, 0 deletions

diff --git a/src/gui/itemviews/qheaderview.cpp b/src/gui/itemviews/qheaderview.cpp
index 3c9ff8b..4fa155a 100644
--- a/src/gui/itemviews/qheaderview.cpp
+++ b/src/gui/itemviews/qheaderview.cpp
@@ -509,6 +509,8 @@ void QHeaderView::setOffsetToLastSection()
 int QHeaderView::length() const
 {
     Q_D(const QHeaderView);
+    d->executePostedLayout();
+    d->executePostedResize();
     //Q_ASSERT(d->headerLength() == d->length);
     return d->length;
 }
diff --git a/tests/auto/qheaderview/tst_qheaderview.cpp b/tests/auto/qheaderview/tst_qheaderview.cpp
index 1d41069..6e68564 100644
--- a/tests/auto/qheaderview/tst_qheaderview.cpp
+++ b/tests/auto/qheaderview/tst_qheaderview.cpp
@@ -194,6 +194,7 @@ private slots:
     void QTBUG7833_sectionClicked();
     void QTBUG8650_crashOnInsertSections();
     void QTBUG12268_hiddenMovedSectionSorting();
+    void QTBUG14242_hideSectionAutoSize();
 
     void initialSortOrderRole();
 
@@ -2109,6 +2110,23 @@ void tst_QHeaderView::QTBUG12268_hiddenMovedSectionSorting()
     QCOMPARE(view.horizontalHeader()->hiddenSectionCount(), 1);
 }
 
+void tst_QHeaderView::QTBUG14242_hideSectionAutoSize()
+{
+    QTableView qtv;
+    QStandardItemModel amodel(4, 4);
+    qtv.setModel(&amodel);
+    QHeaderView *hv = qtv.verticalHeader();
+    hv->setDefaultSectionSize(25);
+    hv->setResizeMode(QHeaderView::ResizeToContents);
+    qtv.show();
+    hv->hideSection(0);
+    int afterlength = hv->length();
+    int calced_length = 0;
+    for (int u = 0; u < hv->count(); ++u)
+        calced_length += hv->sectionSize(u);
+    QVERIFY(calced_length == afterlength);
+}
+
 void tst_QHeaderView::initialSortOrderRole()
 {
     QTableView view;