adjust wrangler patching logic to use the correct node_modules/next/dist directory

Author: dario-piotrowicz

packages/cloudflare/src/cli/build/patches/to-investigate/wrangler-deps.ts

@@ -5,22 +5,15 @@ import path from "node:path";
 export function patchWranglerDeps(config: Config) {
   console.log("# patchWranglerDeps");
 
+  const distPath = getDistPath(config);
   // Patch .next/standalone/node_modules/next/dist/compiled/next-server/pages.runtime.prod.js
   //
   // Remove the need for an alias in wrangler.toml:
   //
   // [alias]
   // # critters is `require`d from `pages.runtime.prod.js` when running wrangler dev, so we need to stub it out
   // "critters" = "./.next/standalone/node_modules/cf/templates/shims/empty.ts"
-  const pagesRuntimeFile = path.join(
-    config.paths.standaloneApp,
-    "node_modules",
-    "next",
-    "dist",
-    "compiled",
-    "next-server",
-    "pages.runtime.prod.js"
-  );
+  const pagesRuntimeFile = path.join(distPath, "compiled", "next-server", "pages.runtime.prod.js");
 
   const patchedPagesRuntime = fs
     .readFileSync(pagesRuntimeFile, "utf-8")
@@ -38,20 +31,36 @@ export function patchWranglerDeps(config: Config) {
   // #            try block here: https://github.com/vercel/next.js/blob/9e8266a7/packages/next/src/server/lib/trace/tracer.ts#L27-L31
   // #            causing the code to require the 'next/dist/compiled/@opentelemetry/api' module instead (which properly works)
   // #"@opentelemetry/api" = "./.next/standalone/node_modules/cf/templates/shims/throw.ts"
-  const tracerFile = path.join(
-    config.paths.standaloneApp,
-    "node_modules",
-    "next",
-    "dist",
-    "server",
-    "lib",
-    "trace",
-    "tracer.js"
-  );
+  const tracerFile = path.join(distPath, "server", "lib", "trace", "tracer.js");
 
   const pacthedTracer = fs
     .readFileSync(tracerFile, "utf-8")
     .replaceAll(/\w+\s*=\s*require\([^/]*opentelemetry.*\)/g, `throw new Error("@opentelemetry/api")`);
 
   writeFileSync(tracerFile, pacthedTracer);
 }
+
+/**
+ * Next.js saves the node_modules/next/dist directory in either the standaloneApp path or in the
+ * standaloneRoot path, this depends on where the next dependency is actually saved (
+ * https://github.com/vercel/next.js/blob/39e06c75/packages/next/src/build/webpack-config.ts#L103-L104
+ * ) and can depend on the package manager used, if it is using workspaces, etc...
+ *
+ * This function checks the two potential paths for the dist directory and returns the first that it finds,
+ * it throws an error if it can't find either
+ *
+ * @param config
+ * @returns the node_modules/next/dist directory path
+ */
+function getDistPath(config: Config): string {
+  for (const root of [config.paths.standaloneApp, config.paths.standaloneRoot]) {
+    try {
+      const distPath = path.join(root, "node_modules", "next", "dist");
+      if (fs.statSync(distPath).isDirectory()) return distPath;
+    } catch {
+      /* empty */
+    }
+  }
+
+  throw new Error("Unexpected error: unable to detect the node_modules/next/dist directory");
+}

packages/cloudflare/src/cli/config.ts

@@ -18,6 +18,8 @@ export type Config = {
     builderOutput: string;
     // Path to the app's `.next` directory (where `next build` saves the build output)
     dotNext: string;
+    // Path to the application standalone root directory
+    standaloneRoot: string;
     // Path to the application standalone directory (where `next build` saves the standalone app)
     standaloneApp: string;
     // Path to the `.next` directory specific to the standalone application
@@ -47,7 +49,8 @@ export type Config = {
 export function getConfig(appDir: string, outputDir: string): Config {
   const dotNext = path.join(outputDir, ".next");
   const appPath = getNextjsApplicationPath(dotNext).replace(/\/$/, "");
-  const standaloneApp = path.join(dotNext, "standalone", appPath);
+  const standaloneRoot = path.join(dotNext, "standalone");
+  const standaloneApp = path.join(standaloneRoot, appPath);
   const standaloneAppDotNext = path.join(standaloneApp, ".next");
   const standaloneAppServer = path.join(standaloneAppDotNext, "server");
 
@@ -59,6 +62,7 @@ export function getConfig(appDir: string, outputDir: string): Config {
       nextApp: appDir,
       builderOutput: outputDir,
       dotNext,
+      standaloneRoot,
       standaloneApp,
       standaloneAppDotNext,
       standaloneAppServer,