Show a full error page to indicate that the resource wasn't found

BUG: 391756

discover/DiscoverObject.cpp

@@ -229,7 +229,7 @@ void DiscoverObject::openApplication(const QUrl& url)
                     emit openApplicationInternal(res.first());
                 } else {
                     rootObject()->setProperty("defaultStartup", true);
-                    showPassiveNotification(i18n("Couldn't open %1", url.toDisplayString()));
+                    Q_EMIT openErrorPage(i18n("Couldn't open %1", url.toDisplayString()));
                 }
             });
         }

discover/DiscoverObject.h

@@ -81,6 +81,7 @@ class DiscoverObject : public QObject
         void compactModeChanged(CompactMode compactMode);
         void preventedClose();
         void unableToFind(const QString &resid);
+        void openErrorPage(const QString &errorMessage);
 
     private:
         void integrateObject(QObject* object);

discover/qml/DiscoverWindow.qml

@@ -117,6 +117,12 @@ Kirigami.ApplicationWindow
             Navigation.openApplicationList({search: search})
         }
 
+        onOpenErrorPage: {
+            Navigation.clearStack()
+            console.warn("error", errorMessage)
+            window.stack.push(errorPageComponent, { error: errorMessage, title: i18n("Sorry...") })
+        }
+
         onPreventedClose: showPassiveNotification(i18n("Could not close the application, there are tasks that need to be done."))
         onUnableToFind: {
             showPassiveNotification(i18n("Unable to find resource: %1", resid));
@@ -132,6 +138,20 @@ Kirigami.ApplicationWindow
         }
     }
 
+    Component {
+        id: errorPageComponent
+        Kirigami.Page {
+            id: page
+            property string error: ""
+            Kirigami.Heading {
+                text: page.error
+                anchors.fill: parent
+                horizontalAlignment: Text.AlignHCenter
+                verticalAlignment: Text.AlignVCenter
+            }
+        }
+    }
+
     Component {
         id: proceedDialog
         Kirigami.OverlaySheet {