(HARP-11087): Evaluate Tiles from removed DataSources as not visible (#…

…1676)

Signed-off-by: Frauke Fritz <frauke.fritz@here.com>

@here/harp-mapview/lib/Tile.ts

@@ -367,7 +367,15 @@ export class Tile implements CachedResource {
         // This happens in order to prevent that, during VisibleTileSet visibility evaluation,
         // visible tiles that haven't yet been evaluated for the current frame are preemptively
         // removed from [[DataSourceCache]].
-        return this.frameNumLastRequested >= this.dataSource.mapView.frameNumber - 1;
+        // There is cases when a tile was already removed from the MapView, i.e. the PolaCaps
+        // Datasource might get remove on a change of projection, in this case
+        // this.dataSource.mapView will throw an error
+        try {
+            return this.frameNumLastRequested >= this.dataSource.mapView.frameNumber - 1;
+        } catch (error) {
+            logger.debug(error);
+            return false;
+        }
     }
 
     set isVisible(visible: boolean) {

@here/harp-mapview/test/TileTest.ts

@@ -41,7 +41,10 @@ function createFakeTextElement(): TextElement {
 describe("Tile", function() {
     const tileKey = TileKey.fromRowColumnLevel(0, 0, 0);
     const stubDataSource = new TileTestStubDataSource({ name: "test-data-source" });
-    const mapView = { projection: mercatorProjection };
+    const mapView = {
+        projection: mercatorProjection,
+        frameNumber: 0
+    };
     stubDataSource.attach(mapView as MapView);
 
     it("set empty decoded tile forces hasGeometry to be true", function() {
@@ -256,4 +259,15 @@ describe("Tile", function() {
         expect(tile.geoBox).deep.equals(expectedGeoBox);
         expect(tile.boundingBox).deep.equals(expectedBBox);
     });
+
+    it("doesnt throw on isVisble if not attached to a MapView", function() {
+        const tile = new Tile(stubDataSource, tileKey);
+        mapView.frameNumber = 2;
+        tile.frameNumLastRequested = 2;
+        expect(tile.isVisible).not.throw;
+        expect(tile.isVisible).is.true;
+        stubDataSource.detach(mapView as MapView);
+        expect(tile.isVisible).not.throw;
+        expect(tile.isVisible).is.false;
+    });
 });