Fix QSFPM not emitting dataChanged when source model is set

QSortFilterProxyModel did not emit dataChanged when calling
setSourceModel() after modifying the source model.
QSortFilterProxyModel::setSourceModel and
QSortFilterProxyModelPrivate::_q_sourceReset(), _q_clearMapping
is called to delete the source_index_mapping. They also need to
call create_mapping function to re-create it.

Fixes: QTBUG-87781
Change-Id: Idbe34696c9d3a2fbf354b653c870bac61378811d
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit 8455bfee76ed3f1bd3bba8bd3688a7afa94ae0bb)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 30 insertions, 0 deletions

diff --git a/tests/auto/corelib/itemmodels/qsortfilterproxymodel_common/tst_qsortfilterproxymodel.cpp b/tests/auto/corelib/itemmodels/qsortfilterproxymodel_common/tst_qsortfilterproxymodel.cpp
index 7f9a996136..729c563981 100644
--- a/tests/auto/corelib/itemmodels/qsortfilterproxymodel_common/tst_qsortfilterproxymodel.cpp
+++ b/tests/auto/corelib/itemmodels/qsortfilterproxymodel_common/tst_qsortfilterproxymodel.cpp
@@ -2191,6 +2191,35 @@ void tst_QSortFilterProxyModel::changeSourceDataForwardsRoles_qtbug35440()
     QCOMPARE(spy.at(1).at(2).value<QVector<int> >(), expectedChangedRoles);
 }
 
+void tst_QSortFilterProxyModel::changeSourceDataProxySendDataChanged_qtbug87781()
+{
+    QStandardItemModel baseModel;
+    QSortFilterProxyModel proxyModelBefore;
+    QSortFilterProxyModel proxyModelAfter;
+
+    QSignalSpy baseDataChangedSpy(&baseModel, &QStandardItemModel::dataChanged);
+    QSignalSpy beforeDataChangedSpy(&proxyModelBefore, &QSortFilterProxyModel::dataChanged);
+    QSignalSpy afterDataChangedSpy(&proxyModelAfter, &QSortFilterProxyModel::dataChanged);
+
+    QVERIFY(baseDataChangedSpy.isValid());
+    QVERIFY(beforeDataChangedSpy.isValid());
+    QVERIFY(afterDataChangedSpy.isValid());
+
+    proxyModelBefore.setSourceModel(&baseModel);
+    baseModel.insertRows(0, 1);
+    baseModel.insertColumns(0, 1);
+    proxyModelAfter.setSourceModel(&baseModel);
+
+    QCOMPARE(baseDataChangedSpy.size(), 0);
+    QCOMPARE(beforeDataChangedSpy.size(), 0);
+    QCOMPARE(afterDataChangedSpy.size(), 0);
+
+    baseModel.setData(baseModel.index(0, 0), QStringLiteral("new data"), Qt::DisplayRole);
+    QCOMPARE(baseDataChangedSpy.size(), 1);
+    QCOMPARE(beforeDataChangedSpy.size(), 1);
+    QCOMPARE(afterDataChangedSpy.size(), 1);
+}
+
 void tst_QSortFilterProxyModel::sortFilterRole()
 {
     QStandardItemModel model;
diff --git a/tests/auto/corelib/itemmodels/qsortfilterproxymodel_common/tst_qsortfilterproxymodel.h b/tests/auto/corelib/itemmodels/qsortfilterproxymodel_common/tst_qsortfilterproxymodel.h
index 71662bda07..44693d4fd2 100644
--- a/tests/auto/corelib/itemmodels/qsortfilterproxymodel_common/tst_qsortfilterproxymodel.h
+++ b/tests/auto/corelib/itemmodels/qsortfilterproxymodel_common/tst_qsortfilterproxymodel.h
@@ -90,6 +90,7 @@ private slots:
     void changeSourceData();
     void changeSourceDataKeepsStableSorting_qtbug1548();
     void changeSourceDataForwardsRoles_qtbug35440();
+    void changeSourceDataProxySendDataChanged_qtbug87781();
     void resortingDoesNotBreakTreeModels();
     void dynamicFilterWithoutSort();
     void sortFilterRole();