Fix missing handling of columns when merging selection ranges

This commit fixes two bugs:
1) Two ranges should not be merged if they are of different columns.
The old code would have merged (0,0) with (1, 1). Tranforming a selection
of just two indexes in a rectangle of four indexes.
2) The QItemSelectionRange appended had wrong column and worked only for
indexes of the first column. For example if 'tl' was (0, 1) than br was (0, 1)
so the QItemSelectionRange would have be ((0,1), (0, 1-1)) so ((0,1), (0,0)).
This QItemSelectionRange is invalid because topLeft columns is greater than
bottomRight column. The fix take in consideration the bottomRight column.

Task-number: QTBUG-58871
Change-Id: I591ef0bcc63926f24a7b1ced002af9b7737a4b6e
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

1 files changed, 74 insertions, 0 deletions

diff --git a/tests/auto/corelib/itemmodels/qitemselectionmodel/tst_qitemselectionmodel.cpp b/tests/auto/corelib/itemmodels/qitemselectionmodel/tst_qitemselectionmodel.cpp
index fb3968c838..b05e3968ea 100644
--- a/tests/auto/corelib/itemmodels/qitemselectionmodel/tst_qitemselectionmodel.cpp
+++ b/tests/auto/corelib/itemmodels/qitemselectionmodel/tst_qitemselectionmodel.cpp
@@ -92,6 +92,9 @@ private slots:
     void QTBUG48402_data();
     void QTBUG48402();
 
+    void QTBUG58851_data();
+    void QTBUG58851();
+
 private:
     QAbstractItemModel *model;
     QItemSelectionModel *selection;
@@ -2848,5 +2851,76 @@ void tst_QItemSelectionModel::QTBUG48402()
     QCOMPARE(QItemSelectionRange(helper.tl, helper.br), QItemSelectionRange(dtl, dbr));
 }
 
+void tst_QItemSelectionModel::QTBUG58851_data()
+{
+    using IntPair = std::pair<int, int>;
+    using IntPairList = QList<IntPair>;
+    using IntPairPair = std::pair<IntPair, IntPair>;
+    using IntPairPairList = QList<IntPairPair>;
+
+    QTest::addColumn<IntPairPairList>("rangesToSelect");
+    QTest::addColumn<IntPairList>("expectedSelectedIndexesPairs");
+    QTest::newRow("Single index in > 0 column")
+            << (IntPairPairList() << IntPairPair(IntPair(0, 1), IntPair(0, 1)))
+            << (IntPairList() << IntPair(0, 1));
+    QTest::newRow("Rectangle in > 0 column")
+            << (IntPairPairList() << IntPairPair(IntPair(0, 1), IntPair(1, 2)))
+            << (IntPairList() << IntPair(0, 1) << IntPair(0, 2) << IntPair(1, 1) << IntPair(1, 2));
+    QTest::newRow("Diagonal in > 0 column")
+            << (IntPairPairList()
+                << IntPairPair(IntPair(0, 1), IntPair(0, 1))
+                << IntPairPair(IntPair(1, 2), IntPair(1, 2))
+                << IntPairPair(IntPair(2, 3), IntPair(2, 3)))
+            << (IntPairList()
+                << IntPair(0, 1)
+                << IntPair(1, 2)
+                << IntPair(2, 3));
+}
+
+void tst_QItemSelectionModel::QTBUG58851()
+{
+    using IntPair = std::pair<int, int>;
+    using IntPairList = QList<IntPair>;
+    using IntPairPair = std::pair<IntPair, IntPair>;
+    using IntPairPairList = QList<IntPairPair>;
+
+    QFETCH(IntPairPairList, rangesToSelect);
+    QFETCH(IntPairList, expectedSelectedIndexesPairs);
+
+    QStandardItemModel model(4, 4);
+    for (int row = 0; row < model.rowCount(); ++row) {
+        for (int column = 0; column < model.columnCount(); ++column) {
+            QStandardItem *item = new QStandardItem(QString("%0%1").arg(row).arg(column));
+            model.setItem(row, column, item);
+        }
+    }
+
+    QSortFilterProxyModel proxy;
+    proxy.setSourceModel(&model);
+    proxy.setSortRole(Qt::DisplayRole);
+
+    std::vector<QPersistentModelIndex> expectedSelectedIndexes;
+    for (const IntPair &index : expectedSelectedIndexesPairs)
+        expectedSelectedIndexes.emplace_back(proxy.index(index.first, index.second));
+
+    QItemSelectionModel selections(&proxy);
+    for (const IntPairPair &range : rangesToSelect) {
+        const IntPair &tl = range.first;
+        const IntPair &br = range.second;
+        selections.select(QItemSelection(proxy.index(tl.first, tl.second),
+                                         proxy.index(br.first, br.second)),
+                          QItemSelectionModel::Select);
+    }
+
+    for (const QPersistentModelIndex &i : expectedSelectedIndexes) {
+        QVERIFY(selections.isSelected(i));
+    }
+    proxy.sort(1, Qt::DescendingOrder);
+    QCOMPARE(selections.selectedIndexes().count(), (int)expectedSelectedIndexes.size());
+    for (const QPersistentModelIndex &i : expectedSelectedIndexes) {
+        QVERIFY(selections.isSelected(i));
+    }
+}
+
 QTEST_MAIN(tst_QItemSelectionModel)
 #include "tst_qitemselectionmodel.moc"