[remix] Clean up dev symlink upon config error (#9595)

Move the try/catch block to immediately after the symlink call, so that if reading the `remix.config.js` file throws an error or if there's an error parsing the `export const config` in a route, the catch block will clean up after itself properly.

I recommend reviewing with [whitespace changes hidden](https://github.com/vercel/vercel/pull/9595/files?w=1).

packages/remix/src/build.ts

@@ -30,7 +30,7 @@ import type {
   BuildResultV2Typical,
 } from '@vercel/build-utils';
 import type { BaseFunctionConfig } from '@vercel/static-config';
-import type { RemixConfig } from '@remix-run/dev/dist/config';
+import type { AppConfig, RemixConfig } from '@remix-run/dev/dist/config';
 import type { ConfigRoute } from '@remix-run/dev/dist/config/routes';
 import {
   calculateRouteConfigHash,
@@ -111,14 +111,6 @@ export const build: BuildV2 = async ({
     await runNpmInstall(entrypointFsDirname, [], spawnOpts, meta, nodeVersion);
   }
 
-  const remixDevPackageJsonPath = _require.resolve(
-    '@remix-run/dev/package.json',
-    { paths: [entrypointFsDirname] }
-  );
-  const remixVersion = JSON.parse(
-    await fs.readFile(remixDevPackageJsonPath, 'utf8')
-  ).version;
-
   // Make our version of `remix` CLI available to the project's build
   // command by creating a symlink to the copy in our node modules,
   // so that `serverBundles` works: https://github.com/remix-run/remix/pull/5479
@@ -127,15 +119,34 @@ export const build: BuildV2 = async ({
     repoRootPath,
     '@remix-run/dev'
   );
+
+  const remixVersion = JSON.parse(
+    await fs.readFile(join(remixRunDevPath, 'package.json'), 'utf8')
+  ).version;
+
+  let remixConfigWrapped = false;
+  const remixConfigPath = findConfig(entrypointFsDirname, 'remix.config');
+  const renamedRemixConfigPath = remixConfigPath
+    ? `${remixConfigPath}.original${extname(remixConfigPath)}`
+    : undefined;
+
   const backupRemixRunDevPath = `${remixRunDevPath}.__vercel_backup`;
   await fs.rename(remixRunDevPath, backupRemixRunDevPath);
   await fs.symlink(REMIX_RUN_DEV_PATH, remixRunDevPath);
 
+  // These get populated inside the try/catch below
+  let serverBundles: AppConfig['serverBundles'];
+  let remixConfig: RemixConfig;
+  let remixRoutes: ConfigRoute[];
+  const serverBundlesMap = new Map<string, ConfigRoute[]>();
+  const resolvedConfigsMap = new Map<ConfigRoute, ResolvedRouteConfig>();
+
+  try {
     // Make `remix build` output production mode
     spawnOpts.env.NODE_ENV = 'production';
 
-  const remixConfig = await chdirAndReadConfig(entrypointFsDirname);
+    remixConfig = await chdirAndReadConfig(entrypointFsDirname);
-  const remixRoutes = Object.values(remixConfig.routes);
+    remixRoutes = Object.values(remixConfig.routes);
 
     // Read the `export const config` (if any) for each route
     const project = new Project();
@@ -146,7 +157,6 @@ export const build: BuildV2 = async ({
       staticConfigsMap.set(route, staticConfig);
     }
 
-  const resolvedConfigsMap = new Map<ConfigRoute, ResolvedRouteConfig>();
     for (const route of remixRoutes) {
       const config = getResolvedRouteConfig(
         route,
@@ -158,7 +168,6 @@ export const build: BuildV2 = async ({
 
     // Figure out which routes belong to which server bundles
     // based on having common static config properties
-  const serverBundlesMap = new Map<string, ConfigRoute[]>();
     for (const route of remixRoutes) {
       if (isLayoutRoute(route.id, remixRoutes)) continue;
 
@@ -177,7 +186,7 @@ export const build: BuildV2 = async ({
       routesForHash.push(route);
     }
 
-  const serverBundles = Array.from(serverBundlesMap.entries()).map(
+    serverBundles = Array.from(serverBundlesMap.entries()).map(
       ([hash, routes]) => {
         const runtime = resolvedConfigsMap.get(routes[0])?.runtime ?? 'nodejs';
         return {
@@ -189,10 +198,6 @@ export const build: BuildV2 = async ({
 
     // We need to patch the `remix.config.js` file to force some values necessary
     // for a build that works on either Node.js or the Edge runtime
-  const remixConfigPath = findConfig(entrypointFsDirname, 'remix.config');
-  const renamedRemixConfigPath = remixConfigPath
-    ? `${remixConfigPath}.original${extname(remixConfigPath)}`
-    : undefined;
     if (remixConfigPath && renamedRemixConfigPath) {
       await fs.rename(remixConfigPath, renamedRemixConfigPath);
 
@@ -227,10 +232,10 @@ config.serverBundles = ${JSON.stringify(serverBundles)};
 module.exports = config;`;
       }
       await fs.writeFile(remixConfigPath, patchedConfig);
+      remixConfigWrapped = true;
     }
 
     // Run "Build Command"
-  try {
     if (buildCommand) {
       debug(`Executing build command "${buildCommand}"`);
       await execCommand(buildCommand, {
@@ -260,7 +265,7 @@ module.exports = config;`;
     }
   } finally {
     // Clean up our patched `remix.config.js` to be polite
-    if (remixConfigPath && renamedRemixConfigPath) {
+    if (remixConfigWrapped && remixConfigPath && renamedRemixConfigPath) {
       await fs.rename(renamedRemixConfigPath, remixConfigPath);
     }