Fix pages functions using unenv aliased packages

.changeset/unlucky-actors-swim.md

@@ -0,0 +1,5 @@
+---
+"wrangler": patch
+---
+
+fix: prevent \_\_cf_cjs name collision in the hybrid Nodejs compat plugin

fixtures/pages-functions-unenv-alias/functions/[[path]].ts

@@ -0,0 +1,10 @@
+const fetch = require("cross-fetch");
+
+export const onRequest = () => {
+	const supportsDefaultExports = typeof fetch === "function";
+	const supportsNamedExports = typeof fetch.Headers === "function";
+
+	return new Response(
+		supportsDefaultExports && supportsNamedExports ? "OK!" : "KO!"
+	);
+};

fixtures/pages-functions-unenv-alias/package.json

@@ -0,0 +1,25 @@
+{
+	"name": "pages-functions-unenv-alias",
+	"private": true,
+	"sideEffects": false,
+	"scripts": {
+		"check:type": "tsc",
+		"dev:functions-app": "wrangler pages dev --port 8792",
+		"test:ci": "vitest run",
+		"test:watch": "vitest",
+		"type:tests": "tsc -p ./tests/tsconfig.json"
+	},
+	"devDependencies": {
+		"@cloudflare/workers-tsconfig": "workspace:^",
+		"typescript": "catalog:default",
+		"undici": "catalog:default",
+		"vitest": "catalog:default",
+		"wrangler": "workspace:*"
+	},
+	"engines": {
+		"node": ">=16.13"
+	},
+	"volta": {
+		"extends": "../../package.json"
+	}
+}

fixtures/pages-functions-unenv-alias/tests/index.test.ts

@@ -0,0 +1,21 @@
+import { resolve } from "node:path";
+import { fetch } from "undici";
+import { describe, it } from "vitest";
+import { runWranglerPagesDev } from "../../shared/src/run-wrangler-long-lived";
+
+describe("Pages functions with unenv aliased packages", () => {
+	it("should run dev server when requiring an unenv aliased package", async ({
+		expect,
+		onTestFinished,
+	}) => {
+		const { ip, port, stop } = await runWranglerPagesDev(
+			resolve(__dirname, ".."),
+			"./functions",
+			["--port=0", "--inspector-port=0"]
+		);
+		onTestFinished(stop);
+		const response = await fetch(`http://${ip}:${port}/`);
+		const body = await response.text();
+		expect(body).toEqual(`OK!`);
+	});
+});

fixtures/pages-functions-unenv-alias/tests/tsconfig.json

@@ -0,0 +1,7 @@
+{
+	"extends": "@cloudflare/workers-tsconfig/tsconfig.json",
+	"compilerOptions": {
+		"types": ["node"]
+	},
+	"include": ["**/*.ts", "../../../node-types.d.ts"]
+}

fixtures/pages-functions-unenv-alias/tsconfig.json

@@ -0,0 +1,20 @@
+{
+	"compilerOptions": {
+		"target": "ES2020",
+		"esModuleInterop": true,
+		"module": "CommonJS",
+		"lib": ["ES2020"],
+		"types": ["node", "@cloudflare/workers-types"],
+		"moduleResolution": "node",
+		"noEmit": true,
+		"skipLibCheck": true,
+		"checkJs": true
+	},
+	"include": [
+		"apps/workerjs-directory/_worker.js/index.js",
+		"apps/workerjs-file/_worker.js",
+		"functions/[[path]].ts",
+		"tests",
+		"../../node-types.d.ts"
+	]
+}

fixtures/pages-functions-unenv-alias/vitest.config.mts

@@ -0,0 +1,9 @@
+import { defineProject, mergeConfig } from "vitest/config";
+import configShared from "../../vitest.shared";
+
+export default mergeConfig(
+	configShared,
+	defineProject({
+		test: {},
+	})
+);

fixtures/pages-functions-unenv-alias/wrangler.toml

@@ -0,0 +1,3 @@
+name = "pages-functions-unenv-alias"
+compatibility_date = "2024-12-30"
+compatibility_flags = ["nodejs_compat"]

packages/wrangler/src/deployment-bundle/esbuild-plugins/hybrid-nodejs-compat.ts

@@ -143,29 +143,18 @@ function handleUnenvAliasedPackages(
 		};
 	});
 
-	build.initialOptions.banner = { js: "", ...build.initialOptions.banner };
-	build.initialOptions.banner.js += dedent`
-		function __cf_cjs(esm) {
-		  const cjs = 'default' in esm ? esm.default : {};
-			for (const [k, v] of Object.entries(esm)) {
-				if (k !== 'default') {
-					Object.defineProperty(cjs, k, {
-						enumerable: true,
-						value: v,
-					});
-				}
-			}
-			return cjs;
-		}
-		`;
-
 	build.onLoad(
 		{ filter: /.*/, namespace: REQUIRED_UNENV_ALIAS_NAMESPACE },
 		({ path }) => {
 			return {
 				contents: dedent`
 					import * as esm from '${path}';
-					module.exports = __cf_cjs(esm);
+					module.exports = Object.entries(esm)
+								.filter(([k,]) => k !== 'default')
+								.reduce((cjs, [k, value]) =>
+									Object.defineProperty(cjs, k, { value, enumerable: true }),
+									"default" in esm ? esm.default : {}
+								);
 				`,
 				loader: "js",
 			};