Support required properties in model delegates

If a delegates declares a required property of a given name, and that
name exists as a role in the model, we set the property accordingly.
The same holds true for the special properties that come from the
QQmlDelegateModel like "index" and "model".

All roles are still injected into scope and thus accessible;
changing this in Qt5 would be tedious or even impossible while still
maintaining backwardscompatibility with delegates that do not use
required properties.

Change-Id: I4f388ba549c42f1ff9822bdb3b8357c4d45e4b66
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

4 files changed, 194 insertions, 0 deletions

diff --git a/tests/auto/quick/qquickpathview/data/delegateWithRequiredProperties.2.qml b/tests/auto/quick/qquickpathview/data/delegateWithRequiredProperties.2.qml
new file mode 100644
index 0000000000..ae8ca784bc
--- /dev/null
+++ b/tests/auto/quick/qquickpathview/data/delegateWithRequiredProperties.2.qml
@@ -0,0 +1,59 @@
+import QtQuick 2.14
+
+Item {
+    id: root
+    width: 800
+    height: 600
+    property bool working: false
+
+    ListModel {
+        id: myModel
+        ListElement {
+            name: "Bill Jones"
+            place: "Berlin"
+        }
+        ListElement {
+            name: "Jane Doe"
+            place: "Oslo"
+        }
+        ListElement {
+            name: "John Smith"
+            place: "Oulo"
+        }
+    }
+
+    Component {
+        id: delegateComponent
+        Rectangle {
+            id: myDelegate
+            height: 50
+            width: 50
+        required property string name
+        required property int index
+        onNameChanged: () => {if (myDelegate.name === "You-know-who") root.working = true}
+            Text {
+                text: myDelegate.name
+                font.pointSize: 10
+                anchors.fill: myDelegate
+            }
+        }
+    }
+
+    PathView {
+        anchors.fill: parent
+        model: myModel
+        delegate: delegateComponent
+        path: Path {
+            startX: 80; startY: 100
+            PathQuad { x: 120; y: 25; controlX: 260; controlY: 75 }
+            PathQuad { x: 140; y: 100; controlX: -20; controlY: 75 }
+        }
+    }
+    Timer {
+        interval: 1
+        running: true
+        repeat: false
+        onTriggered: () => { myModel.setProperty(1, "name", "You-know-who"); }
+    }
+
+}
diff --git a/tests/auto/quick/qquickpathview/data/delegateWithRequiredProperties.qml b/tests/auto/quick/qquickpathview/data/delegateWithRequiredProperties.qml
new file mode 100644
index 0000000000..5d721fd0c4
--- /dev/null
+++ b/tests/auto/quick/qquickpathview/data/delegateWithRequiredProperties.qml
@@ -0,0 +1,53 @@
+import QtQuick 2.14
+
+Item {
+    width: 400
+    height: 200
+
+    ListModel {
+        id: myModel
+        ListElement {
+            name: "Bill Jones"
+            place: "Berlin"
+        }
+        ListElement {
+            name: "Jane Doe"
+            place: "Oslo"
+        }
+        ListElement {
+            name: "John Smith"
+            place: "Oulo"
+        }
+    }
+
+    Component {
+        id: delegateComponent
+        Rectangle {
+            id: myDelegate
+            required property int index
+            required property string name
+            required property string place
+            height: 100
+            width: 100
+            Text {
+                text: myDelegate.name + " lives in " + myDelegate.place + myDelegate.index
+                font.pointSize: 16
+                anchors.fill: myDelegate
+
+                Component.onCompleted: () => {console.info(myDelegate.name+myDelegate.place+myDelegate.index)}
+            }
+        }
+    }
+
+    PathView {
+        anchors.fill: parent
+        model: myModel
+        delegate: delegateComponent
+        path: Path {
+            startX: 120; startY: 100
+            PathQuad { x: 120; y: 25; controlX: 260; controlY: 75 }
+            PathQuad { x: 120; y: 100; controlX: -20; controlY: 75 }
+        }
+    }
+
+}
diff --git a/tests/auto/quick/qquickpathview/data/delegatewithUnrelatedRequiredPreventsAccessToModel.qml b/tests/auto/quick/qquickpathview/data/delegatewithUnrelatedRequiredPreventsAccessToModel.qml
new file mode 100644
index 0000000000..bf130a2d73
--- /dev/null
+++ b/tests/auto/quick/qquickpathview/data/delegatewithUnrelatedRequiredPreventsAccessToModel.qml
@@ -0,0 +1,52 @@
+import QtQuick 2.14
+
+Item {
+    width: 400
+    height: 200
+
+    ListModel {
+        id: myModel
+        ListElement {
+            name: "Bill Jones"
+            place: "Berlin"
+        }
+        ListElement {
+            name: "Jane Doe"
+            place: "Oslo"
+        }
+        ListElement {
+            name: "John Smith"
+            place: "Oulo"
+        }
+    }
+
+    Component {
+        id: delegateComponent
+        Rectangle {
+            id: myDelegate
+        required property int set
+        set: 42
+            height: 100
+            width: 100
+            Text {
+                text: "Test"
+                font.pointSize: 16
+                anchors.fill: myDelegate
+
+                Component.onCompleted: () => { try {index; console.log(index); console.log(name)} catch(ex) {console.info(ex.name)} }
+            }
+        }
+    }
+
+    PathView {
+        anchors.fill: parent
+        model: myModel
+        delegate: delegateComponent
+        path: Path {
+            startX: 120; startY: 100
+            PathQuad { x: 120; y: 25; controlX: 260; controlY: 75 }
+            PathQuad { x: 120; y: 100; controlX: -20; controlY: 75 }
+        }
+    }
+
+}
diff --git a/tests/auto/quick/qquickpathview/tst_qquickpathview.cpp b/tests/auto/quick/qquickpathview/tst_qquickpathview.cpp
index 8b963117ed..36a242bf3b 100644
--- a/tests/auto/quick/qquickpathview/tst_qquickpathview.cpp
+++ b/tests/auto/quick/qquickpathview/tst_qquickpathview.cpp
@@ -149,6 +149,8 @@ private slots:
     void movementDirection();
     void removePath();
     void objectModelMove();
+    void requiredPropertiesInDelegate();
+    void requiredPropertiesInDelegatePreventUnrelated();
 };
 
 class TestObject : public QObject
@@ -2658,6 +2660,34 @@ void tst_QQuickPathView::objectModelMove()
     }
 }
 
+void tst_QQuickPathView::requiredPropertiesInDelegate()
+{
+    {
+        QTest::ignoreMessage(QtMsgType::QtInfoMsg, "Bill JonesBerlin0");
+        QTest::ignoreMessage(QtMsgType::QtInfoMsg, "Jane DoeOslo1");
+        QTest::ignoreMessage(QtMsgType::QtInfoMsg, "John SmithOulo2");
+        QScopedPointer<QQuickView> window(createView());
+        window->setSource(testFileUrl("delegateWithRequiredProperties.qml"));
+        window->show();
+    }
+    {
+        QScopedPointer<QQuickView> window(createView());
+        window->setSource(testFileUrl("delegateWithRequiredProperties.2.qml"));
+        window->show();
+        QTRY_VERIFY(window->rootObject()->property("working").toBool());
+    }
+}
+
+void tst_QQuickPathView::requiredPropertiesInDelegatePreventUnrelated()
+{
+    QTest::ignoreMessage(QtMsgType::QtInfoMsg, "ReferenceError");
+    QTest::ignoreMessage(QtMsgType::QtInfoMsg, "ReferenceError");
+    QTest::ignoreMessage(QtMsgType::QtInfoMsg, "ReferenceError");
+    QScopedPointer<QQuickView> window(createView());
+    window->setSource(testFileUrl("delegatewithUnrelatedRequiredPreventsAccessToModel.qml"));
+    window->show();
+}
+
 QTEST_MAIN(tst_QQuickPathView)
 
 #include "tst_qquickpathview.moc"