QQmlTableInstanceModel: always emit index changed when an item is reused

When reusing a delegate item, it can sometimes happen that the item
ends up being reused at the same location in the table as it had
before it was pooled. And in that case, we don't emit changes to
index, row and column since they technically didn't change.

The problem is that the model might have changed in-between, e.g if
a row has been removed. And in that case, row and column will, even
when unchanged, point to other parts of the model. So all bindings
needs to be reevaluated to ensure that the values they use are
refreshed.

This patch will therefore ensure that we always emit changes to
the mentioned properties when an item is reused, regardless if
they change or not.

Fixes: QTBUG-79209
Change-Id: Icec201a43a30b9f677303fbf652baf6487621deb
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

1 files changed, 4 insertions, 4 deletions

diff --git a/src/qmlmodels/qqmldelegatemodel.cpp b/src/qmlmodels/qqmldelegatemodel.cpp
index 65c99d9bc0..24632fe16b 100644
--- a/src/qmlmodels/qqmldelegatemodel.cpp
+++ b/src/qmlmodels/qqmldelegatemodel.cpp
@@ -2123,7 +2123,7 @@ void QQmlDelegateModelItem::Dispose()
     delete this;
 }
 
-void QQmlDelegateModelItem::setModelIndex(int idx, int newRow, int newColumn)
+void QQmlDelegateModelItem::setModelIndex(int idx, int newRow, int newColumn, bool alwaysEmit)
 {
     const int prevIndex = index;
     const int prevRow = row;
@@ -2133,11 +2133,11 @@ void QQmlDelegateModelItem::setModelIndex(int idx, int newRow, int newColumn)
     row = newRow;
     column = newColumn;
 
-    if (idx != prevIndex)
+    if (idx != prevIndex || alwaysEmit)
         emit modelIndexChanged();
-    if (row != prevRow)
+    if (row != prevRow || alwaysEmit)
         emit rowChanged();
-    if (column != prevColumn)
+    if (column != prevColumn || alwaysEmit)
         emit columnChanged();
 }