Fix SPA mode when single fetch is enabled

.changeset/single-fetch-spa-mode.md

@@ -0,0 +1,5 @@
+---
+"@remix-run/dev": patch
+---
+
+Fix SPA mode when single fetch is enabled by using streaming entry.server

packages/remix-dev/cli/commands.ts

@@ -303,7 +303,8 @@ export async function generateEntry(
   let defaultEntryClient = path.resolve(defaultsDirectory, "entry.client.tsx");
   let defaultEntryServer = path.resolve(
     defaultsDirectory,
-    ctx?.remixConfig.ssr === false
+    ctx?.remixConfig.ssr === false &&
+      ctx?.remixConfig.future.unstable_singleFetch !== true
       ? `entry.server.spa.tsx`
       : `entry.server.${serverRuntime}.tsx`
   );

packages/remix-dev/config.ts

@@ -469,7 +469,7 @@ export async function resolveConfig(
   let pkgJson = await PackageJson.load(rootDirectory);
   let deps = pkgJson.content.dependencies ?? {};
 
-  if (isSpaMode) {
+  if (isSpaMode && appConfig.future?.unstable_singleFetch != true) {
     // This is a super-simple default since we don't need streaming in SPA Mode.
     // We can include this in a remix-spa template, but right now `npx remix reveal`
     // will still expose the streaming template since that command doesn't have

templates/spa/app/entry.client.tsx

@@ -1,3 +1,9 @@
+/**
+ * By default, Remix will handle hydrating your app on the client for you.
+ * You are free to delete this file if you'd like to, but if you ever want it revealed again, you can run `npx remix reveal` ✨
+ * For more information, see https://remix.run/file-conventions/entry.client
+ */
+
 import { RemixBrowser } from "@remix-run/react";
 import { startTransition, StrictMode } from "react";
 import { hydrateRoot } from "react-dom/client";