chore: make dev overrides work in monorepo

Author: sommeeeer

packages/open-next/src/build/createServerBundle.ts

@@ -302,7 +302,9 @@ async function generateBundle(
       outfile: path.join(outputPath, packagePath, `index.${outfileExt}`),
       banner: {
         js: [
-          `globalThis.monorepoPackagePath = "${packagePath}";`,
+          needsGlobalOutputDir(options)
+            ? `globalThis.outputDir = "${outputDir}"`
+            : "",
           "import process from 'node:process';",
           "import { Buffer } from 'node:buffer';",
           "import { createRequire as topLevelCreateRequire } from 'module';",
@@ -395,3 +397,13 @@ async function minifyServerBundle(outputDir: string) {
     mangle: true,
   });
 }
+
+// Check if we need the outputDir in any dev override
+// Remember to update this if you add a new override that needs the outputDir
+function needsGlobalOutputDir(options: buildHelper.BuildOptions) {
+  return (
+    options.config.default?.override?.wrapper === "express-dev" ||
+    options.config.default.override?.incrementalCache === "fs-dev" ||
+    options.config.default.override?.tagCache === "fs-dev"
+  );
+}

packages/open-next/src/overrides/incrementalCache/fs-dev.ts

@@ -4,7 +4,7 @@ import fs from "node:fs/promises";
 import path from "node:path";
 
 const buildId = process.env.NEXT_BUILD_ID;
-const basePath = path.resolve(process.cwd(), `../../cache/${buildId}`);
+const basePath = path.join(globalThis.outputDir, `cache/${buildId}`);
 
 const getCacheKey = (key: string) => {
   return path.join(basePath, `${key}.cache`);

packages/open-next/src/overrides/tagCache/fs-dev.ts

@@ -1,10 +1,12 @@
 import type { TagCache } from "types/overrides";
 
 import fs from "node:fs";
+import path from "node:path";
 
-// TODO: fix this for monorepo
-const tagFile = "../../dynamodb-provider/dynamodb-cache.json";
-
+const tagFile = path.join(
+  globalThis.outputDir,
+  "dynamodb-provider/dynamodb-cache.json",
+);
 const tagContent = fs.readFileSync(tagFile, "utf-8");
 
 let tags = JSON.parse(tagContent) as {

packages/open-next/src/overrides/wrappers/express-dev.ts

@@ -1,3 +1,4 @@
+import path from "node:path";
 import express from "express";
 
 import type { StreamCreator } from "types/open-next.js";
@@ -6,9 +7,13 @@ import type { WrapperHandler } from "types/overrides.js";
 const wrapper: WrapperHandler = async (handler, converter) => {
   const app = express();
   // To serve static assets
-  app.use(express.static("../../assets"));
+  app.use(express.static(path.join(globalThis.outputDir, "assets")));
+
+  const imageHandlerPath = path.join(
+    globalThis.outputDir,
+    "image-optimization-function/index.mjs",
+  );
 
-  const imageHandlerPath = "../../image-optimization-function/index.mjs";
   const imageHandler = await import(imageHandlerPath).then((m) => m.handler);
 
   app.all("/_next/image", async (req, res) => {

packages/open-next/src/types/global.ts

@@ -220,4 +220,9 @@ declare global {
   var __next_route_preloader: (
     stage: "waitUntil" | "start" | "warmerEvent" | "onDemand",
   ) => Promise<void>;
+
+  /**
+   * This is for dev overrides that needs the output directory.
+   */
+  var outputDir: string;
 }