From 61e0fa5d689264fa776aab4e8f8cd5e6f7b458de Mon Sep 17 00:00:00 2001
From: Mitch Curtis <mitch.curtis@digia.com>
Date: Fri, 2 Nov 2012 17:19:59 +0100
Subject: Make it obvious that adding a QLayout to QSplitter is not supported.
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It does not make sense to add a QLayout to a QSplitter, since the
splitter manages its child widgets in the same manner as a QLayout.
The result of doing so is that the child widgets inside that layout
will lead to the splitter and the layout fighting to position the child
widgets.

QSplitter::addWidget should be used to add widgets directly to the
splitter instead.

Change-Id: I640b463cae8673f87354d28636bff4dd3cfb9679
Reviewed-by: Samu Voutilainen <samu.voutilainen@gmail.com>
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>
---
 src/widgets/widgets/qsplitter.cpp                      |  9 ++++++++-
 tests/auto/widgets/widgets/qsplitter/tst_qsplitter.cpp | 12 +++++++++++-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/widgets/widgets/qsplitter.cpp b/src/widgets/widgets/qsplitter.cpp
index 794a824589..bbd5695e9b 100644
--- a/src/widgets/widgets/qsplitter.cpp
+++ b/src/widgets/widgets/qsplitter.cpp
@@ -917,6 +917,10 @@ QSplitterLayoutStruct *QSplitterPrivate::insertWidget(int index, QWidget *w)
     When you hide() a child its space will be distributed among the
     other children. It will be reinstated when you show() it again.
 
+    \note Adding a QLayout to a QSplitter is not supported (either through
+    setLayout() or making the QSplitter a parent of the QLayout); use addWidget()
+    instead (see example above).
+
     \sa QSplitterHandle, QHBoxLayout, QVBoxLayout, QTabWidget
 */
 
@@ -1207,8 +1211,11 @@ int QSplitter::count() const
 void QSplitter::childEvent(QChildEvent *c)
 {
     Q_D(QSplitter);
-    if (!c->child()->isWidgetType())
+    if (!c->child()->isWidgetType()) {
+        if (c->type() == QEvent::ChildAdded && qobject_cast<QLayout *>(c->child()))
+            qWarning("Adding a QLayout to a QSplitter is not supported.");
         return;
+    }
     QWidget *w = static_cast<QWidget*>(c->child());
     if (c->added() && !d->blockChildAdd && !w->isWindow() && !d->findWidget(w)) {
         d->insertWidget_helper(d->list.count(), w, false);
diff --git a/tests/auto/widgets/widgets/qsplitter/tst_qsplitter.cpp b/tests/auto/widgets/widgets/qsplitter/tst_qsplitter.cpp
index 51132e2116..7f2033f527 100644
--- a/tests/auto/widgets/widgets/qsplitter/tst_qsplitter.cpp
+++ b/tests/auto/widgets/widgets/qsplitter/tst_qsplitter.cpp
@@ -93,7 +93,7 @@ private slots:
     void task169702_sizes();
     void taskQTBUG_4101_ensureOneNonCollapsedWidget_data();
     void taskQTBUG_4101_ensureOneNonCollapsedWidget();
-
+    void setLayout();
 private:
     void removeThirdWidget();
     void addThirdWidget();
@@ -770,5 +770,15 @@ void tst_QSplitter::taskQTBUG_4101_ensureOneNonCollapsedWidget()
     QVERIFY(s.sizes().at(0) > 0);
 }
 
+void tst_QSplitter::setLayout()
+{
+    QSplitter splitter;
+    QVBoxLayout layout;
+    QTest::ignoreMessage(QtWarningMsg, "Adding a QLayout to a QSplitter is not supported.");
+    splitter.setLayout(&layout);
+    // It will work, but we don't recommend it...
+    QCOMPARE(splitter.layout(), &layout);
+}
+
 QTEST_MAIN(tst_QSplitter)
 #include "tst_qsplitter.moc"
-- 
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