Don't crash when columns == 0

Task-number: QTBUG-9805
(cherry picked from commit 3469fe05e4b04567598202fecc16c1decfb3ab63)

3 files changed, 78 insertions, 4 deletions

diff --git a/src/declarative/graphicsitems/qdeclarativepositioners.cpp b/src/declarative/graphicsitems/qdeclarativepositioners.cpp
index d33a8be..f436471 100644
--- a/src/declarative/graphicsitems/qdeclarativepositioners.cpp
+++ b/src/declarative/graphicsitems/qdeclarativepositioners.cpp
@@ -700,14 +700,15 @@ void QDeclarativeGrid::setRows(const int rows)
 
 void QDeclarativeGrid::doPositioning(QSizeF *contentSize)
 {
-    int c=_columns,r=_rows;//Actual number of rows/columns
+    int c = _columns;
+    int r = _rows;
     int numVisible = positionedItems.count();
-    if (_columns==-1 && _rows==-1){
+    if (_columns <= 0 && _rows <= 0){
         c = 4;
         r = (numVisible+3)/4;
-    }else if (_rows==-1){
+    } else if (_rows <= 0){
         r = (numVisible+(_columns-1))/_columns;
-    }else if (_columns==-1){
+    } else if (_columns <= 0){
         c = (numVisible+(_rows-1))/_rows;
     }
 
diff --git a/tests/auto/declarative/qdeclarativepositioners/data/gridzerocolumns.qml b/tests/auto/declarative/qdeclarativepositioners/data/gridzerocolumns.qml
new file mode 100644
index 0000000..052d96b
--- /dev/null
+++ b/tests/auto/declarative/qdeclarativepositioners/data/gridzerocolumns.qml
@@ -0,0 +1,40 @@
+import Qt 4.6
+
+Item {
+    width: 640
+    height: 480
+    Grid {
+        objectName: "grid"
+        columns: 0
+        Rectangle {
+            objectName: "one"
+            color: "red"
+            width: 50
+            height: 50
+        }
+        Rectangle {
+            objectName: "two"
+            color: "green"
+            width: 20
+            height: 50
+        }
+        Rectangle {
+            objectName: "three"
+            color: "blue"
+            width: 50
+            height: 20
+        }
+        Rectangle {
+            objectName: "four"
+            color: "cyan"
+            width: 50
+            height: 50
+        }
+        Rectangle {
+            objectName: "five"
+            color: "magenta"
+            width: 10
+            height: 10
+        }
+    }
+}
diff --git a/tests/auto/declarative/qdeclarativepositioners/tst_qdeclarativepositioners.cpp b/tests/auto/declarative/qdeclarativepositioners/tst_qdeclarativepositioners.cpp
index 08eac0a..8692596 100644
--- a/tests/auto/declarative/qdeclarativepositioners/tst_qdeclarativepositioners.cpp
+++ b/tests/auto/declarative/qdeclarativepositioners/tst_qdeclarativepositioners.cpp
@@ -63,6 +63,7 @@ private slots:
     void test_grid();
     void test_grid_spacing();
     void test_grid_animated();
+    void test_grid_zero_columns();
     void test_propertychanges();
     void test_repeater();
     void test_flow();
@@ -414,6 +415,38 @@ void tst_QDeclarativePositioners::test_grid_animated()
     QTRY_COMPARE(five->y(), 50.0);
 
 }
+
+void tst_QDeclarativePositioners::test_grid_zero_columns()
+{
+    QDeclarativeView *canvas = createView(SRCDIR "/data/gridzerocolumns.qml");
+
+    QDeclarativeRectangle *one = canvas->rootObject()->findChild<QDeclarativeRectangle*>("one");
+    QVERIFY(one != 0);
+    QDeclarativeRectangle *two = canvas->rootObject()->findChild<QDeclarativeRectangle*>("two");
+    QVERIFY(two != 0);
+    QDeclarativeRectangle *three = canvas->rootObject()->findChild<QDeclarativeRectangle*>("three");
+    QVERIFY(three != 0);
+    QDeclarativeRectangle *four = canvas->rootObject()->findChild<QDeclarativeRectangle*>("four");
+    QVERIFY(four != 0);
+    QDeclarativeRectangle *five = canvas->rootObject()->findChild<QDeclarativeRectangle*>("five");
+    QVERIFY(five != 0);
+
+    QCOMPARE(one->x(), 0.0);
+    QCOMPARE(one->y(), 0.0);
+    QCOMPARE(two->x(), 50.0);
+    QCOMPARE(two->y(), 0.0);
+    QCOMPARE(three->x(), 70.0);
+    QCOMPARE(three->y(), 0.0);
+    QCOMPARE(four->x(), 120.0);
+    QCOMPARE(four->y(), 0.0);
+    QCOMPARE(five->x(), 0.0);
+    QCOMPARE(five->y(), 50.0);
+
+    QDeclarativeItem *grid = canvas->rootObject()->findChild<QDeclarativeItem*>("grid");
+    QCOMPARE(grid->width(), 170.0);
+    QCOMPARE(grid->height(), 60.0);
+}
+
 void tst_QDeclarativePositioners::test_propertychanges()
 {
     QDeclarativeView *canvas = createView(SRCDIR "/data/propertychangestest.qml");