QList/Table/TreeWidgetItem: Allow reseting values by passing the default value

The convenience functions setBackground(), setForeground() and
setSizeHint() a default constructed value as 'reset'. This means a
default constructed QBrush or QSize is returned in the data() function
which leads to an unexpected background or forground color or size hint.
Therefore check if the passed value is a default constructed value and
set an empty QVariant instead which.

[ChangeLog][QtWidgets][ItemViews] The convenience views
QList/Table/TreeWidgetItem now treat a default constructed QBrush or
QSize as an empty QVariant which allows to reset the values set to it's
default values.

Task-number: QTBUG-76423
Change-Id: I840570bbad3e5fd8c5b4b58903b4fd0066dbdeb7
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

9 files changed, 80 insertions, 16 deletions

diff --git a/src/widgets/itemviews/qlistwidget.cpp b/src/widgets/itemviews/qlistwidget.cpp
index e7dcfac403..1931360dbc 100644
--- a/src/widgets/itemviews/qlistwidget.cpp
+++ b/src/widgets/itemviews/qlistwidget.cpp
@@ -987,8 +987,9 @@ QDataStream &operator>>(QDataStream &in, QListWidgetItem &item)
     \fn void QListWidgetItem::setSizeHint(const QSize &size)
     \since 4.1
 
-    Sets the size hint for the list item to be \a size. If no size hint is set,
-    the item delegate will compute the size hint based on the item data.
+    Sets the size hint for the list item to be \a size.
+    If no size hint is set or \a size is invalid, the item
+    delegate will compute the size hint based on the item data.
 */
 
 /*!
@@ -1119,6 +1120,8 @@ void QListWidgetItem::setFlags(Qt::ItemFlags aflags)
     \since 4.2
 
     Sets the background brush of the list item to the given \a brush.
+    Setting a default-constructed brush will let the view use the
+    default color from the style.
 
     \sa background(), setForeground()
 */
@@ -1137,6 +1140,8 @@ void QListWidgetItem::setFlags(Qt::ItemFlags aflags)
     \since 4.2
 
     Sets the foreground brush of the list item to the given \a brush.
+    Setting a default-constructed brush will let the view use the
+    default color from the style.
 
     \sa foreground(), setBackground()
 */
diff --git a/src/widgets/itemviews/qlistwidget.h b/src/widgets/itemviews/qlistwidget.h
index c102b144df..1319d658ab 100644
--- a/src/widgets/itemviews/qlistwidget.h
+++ b/src/widgets/itemviews/qlistwidget.h
@@ -127,7 +127,7 @@ public:
     inline QBrush background() const
         { return qvariant_cast<QBrush>(data(Qt::BackgroundRole)); }
     inline void setBackground(const QBrush &brush)
-        { setData(Qt::BackgroundRole, brush); }
+        { setData(Qt::BackgroundRole, brush.style() != Qt::NoBrush ? QVariant(brush) : QVariant()); }
 
 #if QT_DEPRECATED_SINCE(5, 13)
     QT_DEPRECATED_X ("Use QListWidgetItem::foreground() instead")
@@ -141,7 +141,7 @@ public:
     inline QBrush foreground() const
         { return qvariant_cast<QBrush>(data(Qt::ForegroundRole)); }
     inline void setForeground(const QBrush &brush)
-        { setData(Qt::ForegroundRole, brush); }
+        { setData(Qt::ForegroundRole, brush.style() != Qt::NoBrush ? QVariant(brush) : QVariant()); }
 
     inline Qt::CheckState checkState() const
         { return static_cast<Qt::CheckState>(data(Qt::CheckStateRole).toInt()); }
@@ -151,7 +151,7 @@ public:
     inline QSize sizeHint() const
         { return qvariant_cast<QSize>(data(Qt::SizeHintRole)); }
     inline void setSizeHint(const QSize &size)
-        { setData(Qt::SizeHintRole, size); }
+        { setData(Qt::SizeHintRole, size.isValid() ? QVariant(size) : QVariant()); }
 
     virtual QVariant data(int role) const;
     virtual void setData(int role, const QVariant &value);
diff --git a/src/widgets/itemviews/qtablewidget.cpp b/src/widgets/itemviews/qtablewidget.cpp
index b1dbafa997..91860341ee 100644
--- a/src/widgets/itemviews/qtablewidget.cpp
+++ b/src/widgets/itemviews/qtablewidget.cpp
@@ -1064,8 +1064,8 @@ QTableWidgetSelectionRange::~QTableWidgetSelectionRange()
   \since 4.1
 
   Sets the size hint for the table item to be \a size.
-  If no size hint is set, the item delegate will compute the
-  size hint based on the item data.
+  If no size hint is set or \a size is invalid, the item
+  delegate will compute the size hint based on the item data.
 */
 
 /*!
@@ -1279,6 +1279,8 @@ void QTableWidgetItem::setFlags(Qt::ItemFlags aflags)
     \since 4.2
 
     Sets the item's background brush to the specified \a brush.
+    Setting a default-constructed brush will let the view use the
+    default color from the style.
 
     \sa setForeground()
 */
@@ -1313,6 +1315,8 @@ void QTableWidgetItem::setFlags(Qt::ItemFlags aflags)
     \since 4.2
 
     Sets the item's foreground brush to the specified \a brush.
+    Setting a default-constructed brush will let the view use the
+    default color from the style.
 
     \sa setBackground()
 */
diff --git a/src/widgets/itemviews/qtablewidget.h b/src/widgets/itemviews/qtablewidget.h
index 0d93a0a075..70e2046400 100644
--- a/src/widgets/itemviews/qtablewidget.h
+++ b/src/widgets/itemviews/qtablewidget.h
@@ -146,7 +146,7 @@ public:
     inline QBrush background() const
         { return qvariant_cast<QBrush>(data(Qt::BackgroundRole)); }
     inline void setBackground(const QBrush &brush)
-        { setData(Qt::BackgroundRole, brush); }
+        { setData(Qt::BackgroundRole, brush.style() != Qt::NoBrush ? QVariant(brush) : QVariant()); }
 
 #if QT_DEPRECATED_SINCE(5, 13)
     QT_DEPRECATED_X ("Use QTableWidgetItem::foreground() instead")
@@ -160,7 +160,7 @@ public:
     inline QBrush foreground() const
         { return qvariant_cast<QBrush>(data(Qt::ForegroundRole)); }
     inline void setForeground(const QBrush &brush)
-        { setData(Qt::ForegroundRole, brush); }
+        { setData(Qt::ForegroundRole, brush.style() != Qt::NoBrush ? QVariant(brush) : QVariant()); }
 
     inline Qt::CheckState checkState() const
         { return static_cast<Qt::CheckState>(data(Qt::CheckStateRole).toInt()); }
@@ -170,7 +170,7 @@ public:
     inline QSize sizeHint() const
         { return qvariant_cast<QSize>(data(Qt::SizeHintRole)); }
     inline void setSizeHint(const QSize &size)
-        { setData(Qt::SizeHintRole, size); }
+        { setData(Qt::SizeHintRole, size.isValid() ? QVariant(size) : QVariant()); }
 
     virtual QVariant data(int role) const;
     virtual void setData(int role, const QVariant &value);
diff --git a/src/widgets/itemviews/qtreewidget.cpp b/src/widgets/itemviews/qtreewidget.cpp
index 6d0909108b..cce0773fec 100644
--- a/src/widgets/itemviews/qtreewidget.cpp
+++ b/src/widgets/itemviews/qtreewidget.cpp
@@ -1285,6 +1285,8 @@ bool QTreeWidgetItem::isFirstColumnSpanned() const
 
     Sets the background brush of the label in the given \a column to the
     specified \a brush.
+    Setting a default-constructed brush will let the view use the
+    default color from the style.
 
     \note If \l{Qt Style Sheets} are used on the same widget as setBackground(),
     style sheets will take precedence if the settings conflict.
@@ -1314,6 +1316,8 @@ bool QTreeWidgetItem::isFirstColumnSpanned() const
 
     Returns the brush used to render the foreground (e.g. text) of the
     specified \a column.
+    Setting a default-constructed brush will let the view use the
+    default color from the style.
 
     \sa background()
 */
@@ -1357,8 +1361,8 @@ bool QTreeWidgetItem::isFirstColumnSpanned() const
   \since 4.1
 
   Sets the size hint for the tree item in the given \a column to be \a size.
-  If no size hint is set, the item delegate will compute the size hint based
-  on the item data.
+  If no size hint is set or \a size is invalid, the item
+  delegate will compute the size hint based on the item data.
 */
 
 /*!
diff --git a/src/widgets/itemviews/qtreewidget.h b/src/widgets/itemviews/qtreewidget.h
index bed77b336d..b9543fb954 100644
--- a/src/widgets/itemviews/qtreewidget.h
+++ b/src/widgets/itemviews/qtreewidget.h
@@ -146,7 +146,7 @@ public:
     inline QBrush background(int column) const
         { return qvariant_cast<QBrush>(data(column, Qt::BackgroundRole)); }
     inline void setBackground(int column, const QBrush &brush)
-        { setData(column, Qt::BackgroundRole, brush); }
+        { setData(column, Qt::BackgroundRole, brush.style() != Qt::NoBrush ? QVariant(brush) : QVariant()); }
 
 #if QT_DEPRECATED_SINCE(5, 13)
     QT_DEPRECATED_X ("Use QTreeWidgetItem::foreground() instead")
@@ -160,7 +160,7 @@ public:
     inline QBrush foreground(int column) const
         { return qvariant_cast<QBrush>(data(column, Qt::ForegroundRole)); }
     inline void setForeground(int column, const QBrush &brush)
-        { setData(column, Qt::ForegroundRole, brush); }
+        { setData(column, Qt::ForegroundRole, brush.style() != Qt::NoBrush ? QVariant(brush) : QVariant()); }
 
     inline Qt::CheckState checkState(int column) const
         { return static_cast<Qt::CheckState>(data(column, Qt::CheckStateRole).toInt()); }
@@ -170,7 +170,7 @@ public:
     inline QSize sizeHint(int column) const
         { return qvariant_cast<QSize>(data(column, Qt::SizeHintRole)); }
     inline void setSizeHint(int column, const QSize &size)
-        { setData(column, Qt::SizeHintRole, size); }
+        { setData(column, Qt::SizeHintRole, size.isValid() ? QVariant(size) : QVariant()); }
 
     virtual QVariant data(int column, int role) const;
     virtual void setData(int column, int role, const QVariant &value);
diff --git a/tests/auto/widgets/itemviews/qlistwidget/tst_qlistwidget.cpp b/tests/auto/widgets/itemviews/qlistwidget/tst_qlistwidget.cpp
index cb083fdcbe..dcb932de66 100644
--- a/tests/auto/widgets/itemviews/qlistwidget/tst_qlistwidget.cpp
+++ b/tests/auto/widgets/itemviews/qlistwidget/tst_qlistwidget.cpp
@@ -1512,6 +1512,20 @@ void tst_QListWidget::itemData()
     QCOMPARE(flags.count(), 6);
     for (int i = 0; i < 4; ++i)
         QCOMPARE(flags[Qt::UserRole + i].toString(), QString::number(i + 1));
+
+    item.setBackground(QBrush(Qt::red));
+    item.setForeground(QBrush(Qt::red));
+    item.setSizeHint(QSize(10, 10));
+    QCOMPARE(item.data(Qt::BackgroundRole), QVariant(QBrush(Qt::red)));
+    QCOMPARE(item.data(Qt::ForegroundRole), QVariant(QBrush(Qt::red)));
+    QCOMPARE(item.data(Qt::SizeHintRole), QVariant(QSize(10, 10)));
+    // an empty brush should result in a QVariant()
+    item.setBackground(QBrush());
+    item.setForeground(QBrush());
+    item.setSizeHint(QSize());
+    QCOMPARE(item.data(Qt::BackgroundRole), QVariant());
+    QCOMPARE(item.data(Qt::ForegroundRole), QVariant());
+    QCOMPARE(item.data(Qt::SizeHintRole), QVariant());
 }
 
 void tst_QListWidget::changeDataWithSorting()
diff --git a/tests/auto/widgets/itemviews/qtablewidget/tst_qtablewidget.cpp b/tests/auto/widgets/itemviews/qtablewidget/tst_qtablewidget.cpp
index f640996690..38dae7743f 100644
--- a/tests/auto/widgets/itemviews/qtablewidget/tst_qtablewidget.cpp
+++ b/tests/auto/widgets/itemviews/qtablewidget/tst_qtablewidget.cpp
@@ -1404,9 +1404,17 @@ void tst_QTableWidget::setItemData()
     QCOMPARE(table.currentRoles, QVector<int>({Qt::DisplayRole, Qt::EditRole, Qt::ToolTipRole}));
 
     QCOMPARE(table.model()->data(idx, Qt::DisplayRole).toString(), QLatin1String("Display"));
+    QCOMPARE(table.model()->data(idx, Qt::EditRole).toString(), QLatin1String("Display"));
     QCOMPARE(table.model()->data(idx, Qt::ToolTipRole).toString(), QLatin1String("ToolTip"));
     QCOMPARE(dataChangedSpy.count(), 1);
-    QCOMPARE(idx, qvariant_cast<QModelIndex>(dataChangedSpy.takeFirst().at(0)));
+    QCOMPARE(idx, qvariant_cast<QModelIndex>(dataChangedSpy.first().at(0)));
+    QCOMPARE(idx, qvariant_cast<QModelIndex>(dataChangedSpy.first().at(1)));
+    const auto roles = qvariant_cast<QVector<int>>(dataChangedSpy.first().at(2));
+    QCOMPARE(roles.size(), 3);
+    QVERIFY(roles.contains(Qt::DisplayRole));
+    QVERIFY(roles.contains(Qt::EditRole));
+    QVERIFY(roles.contains(Qt::ToolTipRole));
+    dataChangedSpy.clear();
 
     table.model()->setItemData(idx, data);
     QCOMPARE(dataChangedSpy.count(), 0);
@@ -1416,6 +1424,21 @@ void tst_QTableWidget::setItemData()
     table.model()->setItemData(idx, data);
     QCOMPARE(table.model()->data(idx, Qt::DisplayRole).toString(), QLatin1String("dizplaye"));
     QCOMPARE(dataChangedSpy.count(), 1);
+    QCOMPARE(QVector<int>({Qt::DisplayRole, Qt::EditRole}), qvariant_cast<QVector<int>>(dataChangedSpy.first().at(2)));
+
+    item->setBackground(QBrush(Qt::red));
+    item->setForeground(QBrush(Qt::green));
+    item->setSizeHint(QSize(10, 10));
+    QCOMPARE(item->data(Qt::BackgroundRole), QVariant(QBrush(Qt::red)));
+    QCOMPARE(item->data(Qt::ForegroundRole), QVariant(QBrush(Qt::green)));
+    QCOMPARE(item->data(Qt::SizeHintRole), QVariant(QSize(10, 10)));
+    // an empty brush should result in a QVariant()
+    item->setBackground(QBrush());
+    item->setForeground(QBrush());
+    item->setSizeHint(QSize());
+    QCOMPARE(item->data(Qt::BackgroundRole), QVariant());
+    QCOMPARE(item->data(Qt::ForegroundRole), QVariant());
+    QCOMPARE(item->data(Qt::SizeHintRole), QVariant());
 }
 
 void tst_QTableWidget::cellWidget()
diff --git a/tests/auto/widgets/itemviews/qtreewidget/tst_qtreewidget.cpp b/tests/auto/widgets/itemviews/qtreewidget/tst_qtreewidget.cpp
index 2118bb5a29..7da56ab797 100644
--- a/tests/auto/widgets/itemviews/qtreewidget/tst_qtreewidget.cpp
+++ b/tests/auto/widgets/itemviews/qtreewidget/tst_qtreewidget.cpp
@@ -1994,6 +1994,20 @@ void tst_QTreeWidget::itemData()
         QCOMPARE(flags[Qt::UserRole + i].toString(), QString::number(i + 1));
     flags = widget.model()->itemData(widget.model()->index(0, 1));
     QCOMPARE(flags.count(), 0);
+
+    item.setBackground(0, QBrush(Qt::red));
+    item.setForeground(0, QBrush(Qt::green));
+    item.setSizeHint(0, QSize(10, 10));
+    QCOMPARE(item.data(0, Qt::BackgroundRole), QVariant(QBrush(Qt::red)));
+    QCOMPARE(item.data(0, Qt::ForegroundRole), QVariant(QBrush(Qt::green)));
+    QCOMPARE(item.data(0, Qt::SizeHintRole), QVariant(QSize(10, 10)));
+    // an empty brush should result in a QVariant()
+    item.setBackground(0, QBrush());
+    item.setForeground(0, QBrush());
+    item.setSizeHint(0, QSize());
+    QCOMPARE(item.data(0, Qt::BackgroundRole), QVariant());
+    QCOMPARE(item.data(0, Qt::ForegroundRole), QVariant());
+    QCOMPARE(item.data(0, Qt::SizeHintRole), QVariant());
 }
 
 void tst_QTreeWidget::enableDisable()