TreeView: update currentIndex on model changes

The previous binding was not getting re-evaluated when the model was
being reset or when rows were been inserted or removed.
Here we use a counter variable, whose value change will force the
evaluation of the binding.

Fixes: QTBUG-53097
Change-Id: I76afebbda78ab477cf65631337a8bad51ca5428d
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

2 files changed, 32 insertions, 1 deletions

diff --git a/src/controls/TreeView.qml b/src/controls/TreeView.qml
index 6a38acff..2bedb9e6 100644
--- a/src/controls/TreeView.qml
+++ b/src/controls/TreeView.qml
@@ -49,7 +49,7 @@ BasicTableView {
     property var model: null
     property alias rootIndex: modelAdaptor.rootIndex
 
-    readonly property var currentIndex: modelAdaptor.mapRowToModelIndex(__currentRow)
+    readonly property var currentIndex: modelAdaptor.updateCount, modelAdaptor.mapRowToModelIndex(__currentRow)
     property ItemSelectionModel selection: null
 
     signal activated(var index)
@@ -96,6 +96,12 @@ BasicTableView {
         id: modelAdaptor
         model: root.model
 
+        // Hack to force re-evaluation of the currentIndex binding
+        property int updateCount: 0
+        onModelReset: updateCount++
+        onRowsInserted: updateCount++
+        onRowsRemoved: updateCount++
+
         onExpanded: root.expanded(index)
         onCollapsed: root.collapsed(index)
     }
diff --git a/tests/auto/controls/data/tst_treeview.qml b/tests/auto/controls/data/tst_treeview.qml
index 902d2178..324d9cff 100644
--- a/tests/auto/controls/data/tst_treeview.qml
+++ b/tests/auto/controls/data/tst_treeview.qml
@@ -848,5 +848,30 @@ Item {
             mouseClick(tree, semiIndent + 50, 20 + 50, Qt.LeftButton)
             verify(selectionModel.isSelected(parentItem))
         }
+
+        function test_QTBUG_53097_currentIndex_on_model_reset()
+        {
+            var component = Qt.createComponent("treeview/treeview_1.qml")
+            compare(component.status, Component.Ready)
+            var tree = component.createObject(container);
+            verify(tree !== null, "tree created is null")
+            tree.headerVisible = false
+            var model = tree.model
+            waitForRendering(tree)
+
+            /* Select the first row */
+            verify(!tree.currentIndex.valid)
+            mouseClick(tree, semiIndent + 50, 20, Qt.LeftButton)
+            compare(tree.currentIndex.row, 0)
+
+            spy.clear()
+            spy.target = tree
+            spy.signalName = "currentIndexChanged"
+            compare(spy.count, 0)
+
+            /* delete the row: the currentIndex must be updated */
+            model.removeRows(0, 1)
+            compare(spy.count, 1)
+        }
     }
 }