QFormLayout: Fix assert when showing with hidden rows

Amends a74cdf778c0c72fa22d9354207d729b2cbf88128, after which the
initialization of items in invisible rows is skipped. Since data members
in QFormLayoutItem were lazily initialized, this resulted in out-of-bounds
access of QList entries.

Use member initialization for all QFormLayoutItem fields, and check that
vLayoutIndex is valid before using it to access the list entry. Skip
labels and fields for which it is not initialized.

Add test case. As a drive-by, silence the test's provoked warning
messages via ignoreMessage.

Change-Id: I374b414a51df20b9af3087a2676061fc6b7f23e2
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/tests/auto/widgets/kernel/qformlayout/tst_qformlayout.cpp b/tests/auto/widgets/kernel/qformlayout/tst_qformlayout.cpp
index 30fd60fcab..15658c1b42 100644
--- a/tests/auto/widgets/kernel/qformlayout/tst_qformlayout.cpp
+++ b/tests/auto/widgets/kernel/qformlayout/tst_qformlayout.cpp
@@ -136,6 +136,7 @@ private slots:
     void setWidget();
     void setLayout();
     void hideShowRow();
+    void showWithHiddenRow();
 
 /*
     QLayoutItem *itemAt(int row, ItemRole role) const;
@@ -817,6 +818,7 @@ void tst_QFormLayout::removeRow_QWidget()
     QCOMPARE(layout->rowCount(), 0);
 
     QWidget *w3 = new QWidget;
+    QTest::ignoreMessage(QtWarningMsg, "QFormLayout::takeRow: Invalid widget");
     layout->removeRow(w3);
     delete w3;
 }
@@ -857,6 +859,7 @@ void tst_QFormLayout::removeRow_QLayout()
     QCOMPARE(layout->rowCount(), 0);
 
     QHBoxLayout *l3 = new QHBoxLayout;
+    QTest::ignoreMessage(QtWarningMsg, "QFormLayout::takeRow: Invalid layout");
     layout->removeRow(l3);
     delete l3;
 }
@@ -896,6 +899,7 @@ void tst_QFormLayout::takeRow()
     QCOMPARE(layout->rowCount(), 0);
     QCOMPARE(result.fieldItem->widget(), w1.data());
 
+    QTest::ignoreMessage(QtWarningMsg, "QFormLayout::takeRow: Invalid row 0");
     result = layout->takeRow(0);
 
     QVERIFY(!result.fieldItem);
@@ -936,6 +940,7 @@ void tst_QFormLayout::takeRow_QWidget()
     QCOMPARE(layout->rowCount(), 0);
 
     QWidget *w3 = new QWidget;
+    QTest::ignoreMessage(QtWarningMsg, "QFormLayout::takeRow: Invalid widget");
     result = layout->takeRow(w3);
     delete w3;
 
@@ -983,6 +988,7 @@ void tst_QFormLayout::takeRow_QLayout()
     QCOMPARE(layout->rowCount(), 0);
 
     QHBoxLayout *l3 = new QHBoxLayout;
+    QTest::ignoreMessage(QtWarningMsg, "QFormLayout::takeRow: Invalid layout");
     result = layout->takeRow(l3);
     delete l3;
 
@@ -1012,7 +1018,9 @@ void tst_QFormLayout::setWidget()
     QCOMPARE(layout.rowCount(), 6);
 
     // should be ignored and generate warnings
+    QTest::ignoreMessage(QtWarningMsg, "QFormLayoutPrivate::setItem: Cell (3, 1) already occupied");
     layout.setWidget(3, QFormLayout::FieldRole, &w4);
+    QTest::ignoreMessage(QtWarningMsg, "QFormLayoutPrivate::setItem: Invalid cell (-1, 1)");
     layout.setWidget(-1, QFormLayout::FieldRole, &w4);
 
     {
@@ -1080,7 +1088,9 @@ void tst_QFormLayout::setLayout()
     QCOMPARE(layout.rowCount(), 6);
 
     // should be ignored and generate warnings
+    QTest::ignoreMessage(QtWarningMsg, "QFormLayoutPrivate::setItem: Cell (3, 1) already occupied");
     layout.setLayout(3, QFormLayout::FieldRole, &l4);
+    QTest::ignoreMessage(QtWarningMsg, "QLayout::addChildLayout: layout \"\" already has a parent");
     layout.setLayout(-1, QFormLayout::FieldRole, &l4);
     QCOMPARE(layout.count(), 3);
     QCOMPARE(layout.rowCount(), 6);
@@ -1255,6 +1265,19 @@ void tst_QFormLayout::hideShowRow()
         QVERIFY(rowInputWidget(row)->isHidden());
 }
 
+void tst_QFormLayout::showWithHiddenRow()
+{
+    QWidget topLevel;
+    QFormLayout layout;
+
+    for (int row = 0; row < 3; ++row)
+        layout.addRow(QString("Label %1").arg(row), new QLineEdit);
+    layout.setRowVisible(1, false);
+
+    topLevel.setLayout(&layout);
+    topLevel.show();
+}
+
 void tst_QFormLayout::itemAt()
 {
     QWidget topLevel;