Fix integration test and call handleError on prerender 404s

Author: brophdawg11

.changeset/prerender-spa-fallback.md

@@ -10,3 +10,4 @@ Generate a "SPA fallback" HTML file for scenarios where applications are prerend
   - The generated HTML would include the root index route which prevented hydration for any other paths
   - With this change, we now generate a "SPA Mode" file in `__spa-fallback__.html` that will allow you to hydrate for any non-prerendered paths
   - You can serve this file from your static file server for any paths that would otherwise 404 if you only want to pre-render _some_ routes in your `ssr:false` app and serve the others as a SPA
+  - `npx sirv-cli build/client --single __spa-fallback__.html`

packages/react-router/lib/server-runtime/server.ts

@@ -110,7 +110,7 @@ export const createRequestHandler: CreateRequestHandlerFunction = (
     let normalizedPath = url.pathname
       .replace(/\.data$/, "")
       .replace(/^\/_root$/, "/")
-      .replace(/\/$/, "");
+      .replace(/.\/$/, "");
     let params: RouteMatch<ServerRoute>["params"] = {};
     let handleError = (error: unknown) => {
       if (mode === ServerMode.Development) {
@@ -135,6 +135,20 @@ export const createRequestHandler: CreateRequestHandlerFunction = (
       !_build.prerender.includes(normalizedPath) &&
       !_build.prerender.includes(normalizedPath + "/")
     ) {
+      errorHandler(
+        new ErrorResponseImpl(
+          404,
+          "Not Found",
+          `Refusing to SSR the path \`${normalizedPath}\` because \`ssr:false\` is ` +
+            "set and the path is not included in the `prerender` config, so in " +
+            "production the path will be a 404."
+        ),
+        {
+          context: loadContext,
+          params,
+          request,
+        }
+      );
       return new Response("Not Found", {
         status: 404,
         statusText: "Not Found",