createTemporaryObject: account for undefined parent argument

c837be7beab1c217b8f163b9a2d53ca12fd2c95e results in a warning for code
that does this:

    let parent = createTemporaryObject(window)

The warning was:

"QML Component: Unsuitable arguments passed to createObject(). The first
argument should be a QObject* or null, and the second argument should
be a JavaScript object or a QVariantMap"

Avoid the warning by setting parent to null if it's undefined.

Update the relevant self-tests to fail on warnings so that it's
tested.

Change-Id: I04e9423e7c08d370d8055a8b8e766827a9709919
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
(cherry picked from commit e7f23ef9b09b5fc522598abec20e541490ceba3d)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 11 insertions, 1 deletions

diff --git a/src/qmltest/TestCase.qml b/src/qmltest/TestCase.qml
index 7055bcd974..a69c2fe6f6 100644
--- a/src/qmltest/TestCase.qml
+++ b/src/qmltest/TestCase.qml
@@ -631,6 +631,9 @@ Item {
             throw new Error("QtQuickTest::fail");
         }
 
+        if (parent === undefined)
+            parent = null
+
         var object = component.createObject(parent, properties ? properties : ({}));
         qtest_temporaryObjects.push(object);
         return object;
diff --git a/tests/auto/qmltest/selftests/tst_createTemporaryObject.qml b/tests/auto/qmltest/selftests/tst_createTemporaryObject.qml
index ec3387a38b..a54e5f1e7b 100644
--- a/tests/auto/qmltest/selftests/tst_createTemporaryObject.qml
+++ b/tests/auto/qmltest/selftests/tst_createTemporaryObject.qml
@@ -25,6 +25,8 @@ TestCase {
     }
 
     function init() {
+        failOnWarning(/.?/)
+
         // The items are destroyed after cleanup(), so we check here after every test,
         // and once for the last test in cleanupTestCase().
         verifyNoChildren();
@@ -125,7 +127,8 @@ TestCase {
             { tag: "omit", expectedParent: null },
             { tag: "undefined", parent: undefined, expectedParent: null },
             { tag: "null", parent: null, expectedParent: null },
-            { tag: "1", parent: 1, expectedParent: null },
+            { tag: "1", parent: 1, expectedParent: null,
+                ignoreWarning: /.*Unsuitable arguments passed to createObject.*/ },
             { tag: "testCase", parent: testCase, expectedParent: testCase }
         ];
     }
@@ -133,6 +136,10 @@ TestCase {
     // Tests that an invalid or missing parent argument results in a parentless object.
     // This is the same behavior as displayed by component.createObject().
     function test_fromComponentParent(data) {
+        // ignoreWarning takes precedence over failOnWarning (which we call in init()).
+        if (data.hasOwnProperty("ignoreWarning"))
+            ignoreWarning(data.ignoreWarning)
+
         var object = data.hasOwnProperty("parent")
             ? createTemporaryObject(itemComponent, data.parent)
             : createTemporaryObject(itemComponent);