Do not loop infinitely if a span is larger than the layout extent

There is no point in searching through all cells to see if an item of
columnSpan 3 fits into a layout with 2 columns, since it won't ever
fit.
So instead we detect this case early and ignore the item for
inclusion.

Task-number: QTBUG-35778

Change-Id: I3f7963df17b05b3eb14ba0bae49e5a885d15b33b
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>

2 files changed, 26 insertions, 1 deletions

diff --git a/src/layouts/qquicklinearlayout.cpp b/src/layouts/qquicklinearlayout.cpp
index 2b1ce66e..4f776b1f 100644
--- a/src/layouts/qquicklinearlayout.cpp
+++ b/src/layouts/qquicklinearlayout.cpp
@@ -736,6 +736,9 @@ void QQuickGridLayout::insertLayoutItems()
 
         Q_ASSERT(columnSpan >= 1);
         Q_ASSERT(rowSpan >= 1);
+        const int sp = span[flowOrientation];
+        if (sp > flowBound)
+            return;
 
         if (row >= 0)
             nextRow = row;
@@ -758,7 +761,7 @@ void QQuickGridLayout::insertLayoutItems()
             bool cellAcceptsItem;
             while (true) {
                 // Check if the item does not span beyond the layout bound
-                cellAcceptsItem = (flowColumn + span[flowOrientation]) <= flowBound;
+                cellAcceptsItem = (flowColumn + sp) <= flowBound;
 
                 // Check if all the required cells are not taken
                 for (int rs = 0; cellAcceptsItem && rs < rowSpan; ++rs) {
diff --git a/tests/auto/controls/data/tst_gridlayout.qml b/tests/auto/controls/data/tst_gridlayout.qml
index 0e4f8509..7e6240fd 100644
--- a/tests/auto/controls/data/tst_gridlayout.qml
+++ b/tests/auto/controls/data/tst_gridlayout.qml
@@ -438,6 +438,28 @@ Item {
             layout.destroy();
         }
 
+        Component {
+            id: layout_spanIsMoreThanColumns_Component
+
+            GridLayout {
+                columnSpacing: 1
+                rowSpacing: 1
+                columns: 2
+
+                Rectangle {
+                    implicitWidth: 10
+                    implicitHeight: 10
+                    Layout.columnSpan: 3
+                }
+            }
+        }
+
+        function test_spanIsMoreThanColumns() {
+            var layout = layout_spanIsMoreThanColumns_Component.createObject(container);
+            // item was not added, therefore implicit width is 0
+            compare(layout.implicitWidth, 0);
+            layout.destroy();
+        }
 
         function test_sizeHints() {
             var layout = layout_spanAcrossEmptyRows_Component.createObject(container);