Fix view failing to apply when there is no default view (#70)

No changelog entry because the fix is in undocumented experimental API.

Also fix view overrides not being cleared when applying a new saved view
in the test app.

packages/saved-views-react/src/api/utilities/translation/SavedViewTranslation.ts

@@ -4,8 +4,8 @@
 *--------------------------------------------------------------------------------------------*/
 import { IModelReadRpcInterface, type ViewQueryParams, type ViewStateProps } from "@itwin/core-common";
 import {
-  DisplayStyle3dState, DrawingViewState, EmphasizeElements, SheetViewState, SpatialViewState, type BlankConnection,
-  type IModelConnection, type ViewState, type Viewport,
+  DisplayStyle3dState, DrawingViewState, EmphasizeElements, SheetViewState, SpatialViewState, type IModelConnection,
+  type ViewState, type Viewport,
 } from "@itwin/core-frontend";
 import {
   isViewDataITwin3d, isViewDataITwinDrawing, isViewDataITwinSheet, type SavedViewRepresentation,
@@ -255,10 +255,14 @@ async function fetchIModelViewData(iModel: IModelConnection, viewClassName: View
   }
 
   const viewId = await getDefaultViewIdFromClassName(iModel, viewClassName);
+  if (viewId === "") {
+    return manufactureEmptyViewState(iModel, viewClassName);
+  }
+
   return iModel.views.load(viewId);
 }
 
-function manufactureEmptyViewState(iModel: BlankConnection, viewClassName: ViewTypes): ViewState {
+function manufactureEmptyViewState(iModel: IModelConnection, viewClassName: ViewTypes): ViewState {
   const blankViewState = SpatialViewState.createBlank(
     iModel,
     { x: 0, y: 0, z: 0 },

packages/test-app-frontend/src/App/ITwinJsApp/ITwinJsApp.tsx

@@ -17,7 +17,7 @@ import { FrontendIModelsAccess } from "@itwin/imodels-access-frontend";
 import { IModelsClient } from "@itwin/imodels-client-management";
 import { PageLayout } from "@itwin/itwinui-layouts-react";
 import { useToaster } from "@itwin/itwinui-react";
-import { applyExtensionsToViewport, type LegacySavedViewBase } from "@itwin/saved-views-react/experimental";
+import { ModelCategoryOverrideProvider, applyExtensionsToViewport, type LegacySavedViewBase } from "@itwin/saved-views-react/experimental";
 import { useEffect, useRef, useState, type ReactElement } from "react";
 
 import { applyUrlPrefix } from "../../environment.js";
@@ -73,10 +73,11 @@ export function ITwinJsApp(props: ITwinJsAppProps): ReactElement | null {
   );
 
   const viewportRef = useRef<ScreenViewport>();
-  const handleSavedViewSelect = (savedView: LegacySavedViewBase, viewState: ViewState) => {
+  const handleSavedViewSelect = async (savedView: LegacySavedViewBase, viewState: ViewState) => {
     setViewState(viewState);
-    if (viewportRef.current) {
-      applyExtensionsToViewport(viewportRef.current, savedView);
+    if (iModel && viewportRef.current) {
+      await clearAllOverrides(iModel, viewportRef.current);
+      await applyExtensionsToViewport(viewportRef.current, savedView);
     }
   };
 
@@ -206,3 +207,12 @@ async function getStoredViewState(iModel: IModelConnection): Promise<ViewState |
 
   return viewId ? iModel.views.load(viewId) : undefined;
 }
+
+async function clearAllOverrides(iModel: IModelConnection, viewport: Viewport): Promise<void> {
+  const subcatProvider = viewport.findFeatureOverrideProviderOfType(ModelCategoryOverrideProvider);
+  if (subcatProvider) {
+    viewport.dropFeatureOverrideProvider(subcatProvider);
+  }
+
+  iModel.selectionSet.emptyAll();
+}