StackLayout: Do not set size of children to (-1, -1)

The item-size-hint-cache in StackLayout was not always valid when
QQuickStackLayout::rearrange() was entered, so it would end up setting
the size of the item to (-1, -1)

Fixes: QTBUG-105899
Change-Id: I632aa18bb10b84d59af35cd3c7cb0c675d8d1692
Reviewed-by: Oliver Eftevaag <oliver.eftevaag@qt.io>
(cherry picked from commit 9a4874ab7f18a54b2497f689dfd7f7a2ee0516b8)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 51 insertions, 0 deletions

diff --git a/tests/auto/quick/qquicklayouts/data/tst_stacklayout.qml b/tests/auto/quick/qquicklayouts/data/tst_stacklayout.qml
index a04e7a9dd7..3455dd5cc1 100644
--- a/tests/auto/quick/qquicklayouts/data/tst_stacklayout.qml
+++ b/tests/auto/quick/qquicklayouts/data/tst_stacklayout.qml
@@ -263,5 +263,56 @@ Item {
             compare(layout.implicitWidth, 20)
             compare(layout.implicitHeight, 20)
         }
+
+        Component {
+            id: layout_setCurrentIndex_Component
+
+            StackLayout {
+                width: 200
+                height: 200
+
+                property alias firstItem : rect
+                property alias secondItem: rowLayout
+
+                Rectangle {
+                    id: rect
+                    color: "red"
+                    implicitWidth: 10
+                    implicitHeight: 10
+                }
+                RowLayout {
+                    id: rowLayout
+                    spacing: 0
+                    Rectangle {
+                        color: "green"
+                        implicitWidth: 10
+                        implicitHeight: 10
+                        Layout.fillWidth: true
+                        Layout.fillHeight: true
+                    }
+                    Rectangle {
+                        color: "blue"
+                        implicitWidth: 10
+                        implicitHeight: 10
+                        Layout.fillWidth: true
+                        Layout.fillHeight: true
+                    }
+                }
+            }
+        }
+
+        function test_setCurrentIndex()
+        {
+            var layout = layout_setCurrentIndex_Component.createObject(container)
+            compare(layout.firstItem.width, 200)
+
+            // Invalidate the StackLayout (and its cached size hints)
+            layout.firstItem.implicitWidth = 42
+
+            layout.currentIndex = 1
+            compare(layout.secondItem.width, 200)   // width should not be -1
+            layout.destroy()
+        }
+
     }
 }