QSqlTableModel::removeRows() enforce edit strategy

For OnFieldChange and OnRowChange, we don't want more than one row in
the cache with uncommitted changes. This could happen if deletion in
the database fails while other changes are pending.

Chosen solution is to return false if other rows have pending changes.
Also, we only allow 1 row removed at a time.

Updated test, changes and documentation.

Change-Id: I68baf6d221789b4754e891535070011c759a2155
Reviewed-by: Honglei Zhang <honglei.zhang@nokia.com>

dist/changes-5.0.0

@@ -413,6 +413,9 @@ model methods setData() or setRecord().
 before doing anything. Previously, it would remove what it could and
 ignore the rest of the range.
 
+* removeRows(), for OnFieldChange and OnRowChange, allows only 1 row to be
+removed and only if there are no other changed rows.
+
 * setRecord() and insertRecord()
   -Only use fields where generated flag is set to true. This is
   is consistent with the meaning of the flag.

src/sql/models/qsqltablemodel.cpp

@@ -1021,11 +1021,18 @@ bool QSqlTableModel::removeColumns(int column, int count, const QModelIndex &par
     an invalid model index.
 
     When the edit strategy is OnManualSubmit, deletion of rows from
-    the database is delayed until submitAll() is called; otherwise,
-    deletions are immediate.
+    the database is delayed until submitAll() is called.
 
-    Inserted but not yet submitted rows in the range to be removed
-    are immediately removed from the model.
+    For OnFieldChange and OnRowChange, only one row may be deleted
+    at a time and only if no other row has a cached change. Deletions
+    are submitted immediately to the database. The model retains a
+    blank row for successfully deleted row until refreshed with select().
+
+    After failed deletion, the operation is not reverted in the model.
+    The application may resubmit or revert.
+
+    Inserted but not yet successfully submitted rows in the range to be
+    removed are immediately removed from the model.
 
     Before a row is deleted from the database, the beforeDelete()
     signal is emitted.
@@ -1047,6 +1054,10 @@ bool QSqlTableModel::removeRows(int row, int count, const QModelIndex &parent)
     else if (!count)
         return true;
 
+    if (d->strategy != OnManualSubmit)
+        if (count > 1 || (d->cache.value(row).submitted() && isDirty()))
+            return false;
+
     // Iterate backwards so we don't have to worry about removed rows causing
     // higher cache entries to shift downwards.
     for (int idx = row + count - 1; idx >= row; --idx) {

tests/auto/sql/models/qsqltablemodel/tst_qsqltablemodel.cpp

@@ -592,6 +592,8 @@ void tst_QSqlTableModel::insertRowFailure()
         QCOMPARE(model.data(model.index(1, 1)).toString(), QString("blah"));
         QFAIL_SQL(model, insertRow(2));
         QCOMPARE(model.rowCount(), 2);
+        QFAIL_SQL(model, removeRow(1));
+        QCOMPARE(model.rowCount(), 2);
     } else {
         QVERIFY_SQL(model, setData(model.index(1, 1), QString("eggs")));
         QCOMPARE(model.data(model.index(1, 1)).toString(), QString("eggs"));
@@ -599,6 +601,8 @@ void tst_QSqlTableModel::insertRowFailure()
         QCOMPARE(model.data(model.index(1, 1)).toString(), QString("spam"));
         QVERIFY_SQL(model, insertRow(2));
         QCOMPARE(model.rowCount(), 3);
+        QVERIFY_SQL(model, removeRow(1));
+        QCOMPARE(model.rowCount(), 3);
     }
 
     // restore empty table
@@ -795,8 +799,10 @@ void tst_QSqlTableModel::removeRows()
     QVERIFY(!model.removeRows(1, 0)); // zero count
     QVERIFY(!model.removeRows(5, 1)); // past end (DOESN'T causes a beforeDelete to be emitted)
     QVERIFY(!model.removeRows(1, 0, model.index(2, 0))); // can't pass a valid modelindex
+    QFAIL_SQL(model, removeRows(0, 2)); // more than 1 row on OnFieldChange
 
-    QVERIFY_SQL(model, removeRows(0, 2));
+    QVERIFY_SQL(model, removeRows(0, 1));
+    QVERIFY_SQL(model, removeRows(1, 1));
     QCOMPARE(beforeDeleteSpy.count(), 2);
     QVERIFY(beforeDeleteSpy.at(0).at(0).toInt() == 0);
     QVERIFY(beforeDeleteSpy.at(1).at(0).toInt() == 1);
@@ -1079,6 +1085,7 @@ void tst_QSqlTableModel::isDirty()
         QFAIL_SQL(model, setData(model.index(1, 1), QString("sam i am")));
         QFAIL_SQL(model, setRecord(1, model.record(1)));
         QFAIL_SQL(model, insertRow(1));
+        QFAIL_SQL(model, removeRow(1));
         QFAIL_SQL(model, isDirty(model.index(1, 1)));
 
         model.revertAll();