fix: simplify debug package resolution (#10374)

Author: edmundhung

.changeset/wild-actors-burn.md

@@ -0,0 +1,8 @@
+---
+"@cloudflare/unenv-preset": patch
+"wrangler": patch
+---
+
+Simplify debug package resolution with nodejs_compat
+
+A patched version of `debug` was previously introduced that resolved the package to a custom implementation. However, this caused issues due to CJS/ESM interop problems. We now resolve the `debug` package to use the Node.js implementation instead.

fixtures/nodejs-hybrid-app/package.json

@@ -10,7 +10,9 @@
 "devDependencies": {
 "@cloudflare/workers-tsconfig": "workspace:*",
 "@cloudflare/workers-types": "catalog:default",
+"@types/debug": "4.1.12",
 "@types/pg": "^8.11.2",
+"debug": "4.4.1",
 "pg": "8.11.3",
 "pg-cloudflare": "^1.1.1",
 "undici": "catalog:default",

fixtures/nodejs-hybrid-app/src/index.ts

@@ -42,6 +42,10 @@ export default {
 return await testSqlite();
 case "/test-http":
 return await testHttp();
+case "/test-debug-import":
+return await testDebugImport();
+case "/test-debug-require":
+return await testDebugRequire();
 }
 
 return new Response(
@@ -55,6 +59,8 @@ export default {
 <a href="test-crypto">node:crypto</a>
 <a href="test-sqlite">node:sqlite</a>
 <a href="test-http">node:http</a>
+<a href="test-debug-import">debug (import)</a>
+<a href="test-debug-require">debug (require)</a>
 `,
 { headers: { "Content-Type": "text/html; charset=utf-8" } }
 );
@@ -281,3 +287,67 @@ async function testHttp() {
 
 return new Response("OK");
 }
+
+async function testDebugImport() {
+const debug = (await import("debug")).default;
+const capturedLogs: string[] = [];
+
+// Override debug.log to capture output for verification
+debug.log = (...args: string[]) => {
+capturedLogs.push(args.join(" "));
+};
+
+// Test different namespaces based on DEBUG env var: "example:*,test"
+const testNamespace = debug("test"); // Should log (matches "test")
+const exampleNamespace = debug("example"); // Should NOT log (doesn't match "example:*")
+const exampleFooNamespace = debug("example:foo"); // Should log (matches "example:*")
+
+testNamespace("Test import message 1");
+exampleNamespace("Example import message (should not appear)");
+exampleFooNamespace("Example foo import message");
+
+if (testNamespace.enabled) {
+testNamespace("Test import enabled message");
+}
+
+// Strip timestamps from captured logs, keeping namespace and message
+// Format: "2025-08-14T20:09:49.769Z test Test import message 1"
+const logsWithoutTimestamp = capturedLogs.map((log) => {
+const parts = log.split(" ");
+return parts.slice(1).join(" "); // Remove timestamp, keep namespace + message
+});
+
+return Response.json(logsWithoutTimestamp);
+}
+
+async function testDebugRequire() {
+const debug = require("debug");
+const capturedLogs: string[] = [];
+
+// Override debug.log to capture output for verification
+debug.log = (...args: string[]) => {
+capturedLogs.push(args.join(" "));
+};
+
+// Test different namespaces based on DEBUG env var: "example:*,test"
+const testNamespace = debug("test"); // Should log (matches "test")
+const exampleNamespace = debug("example"); // Should NOT log (doesn't match "example:*")
+const exampleFooNamespace = debug("example:foo"); // Should log (matches "example:*")
+
+testNamespace("Test require message 1");
+exampleNamespace("Example require message (should not appear)");
+exampleFooNamespace("Example foo require message");
+
+if (testNamespace.enabled) {
+testNamespace("Test require enabled message");
+}
+
+// Strip timestamps from captured logs, keeping namespace and message
+// Format: "2025-08-14T20:09:49.769Z test Test require message 1"
+const logsWithoutTimestamp = capturedLogs.map((log) => {
+const parts = log.split(" ");
+return parts.slice(1).join(" "); // Remove timestamp, keep namespace + message
+});
+
+return Response.json(logsWithoutTimestamp);
+}

fixtures/nodejs-hybrid-app/tests/index.test.ts

@@ -89,6 +89,26 @@ describe("nodejs compat", () => {
 await expect(response.text()).resolves.toBe("OK");
 });
 
+test("debug import", async ({ expect }) => {
+const { ip, port } = wrangler;
+const response = await fetch(`http://${ip}:${port}/test-debug-import`);
+await expect(response.json()).resolves.toEqual([
+"test Test import message 1",
+"example:foo Example foo import message",
+"test Test import enabled message",
+]);
+});
+
+test("debug require", async ({ expect }) => {
+const { ip, port } = wrangler;
+const response = await fetch(`http://${ip}:${port}/test-debug-require`);
+await expect(response.json()).resolves.toEqual([
+"test Test require message 1",
+"example:foo Example foo require message",
+"test Test require enabled message",
+]);
+});
+
 test("process.env contains vars", async ({ expect }) => {
 const { ip, port } = wrangler;
 const response = await fetch(`http://${ip}:${port}/process-env`);

fixtures/nodejs-hybrid-app/wrangler.jsonc

@@ -16,5 +16,6 @@
 "DB_NAME": "pfmegrnargs",
 "DB_USERNAME": "reader",
 "DB_PASSWORD": "NWDMCE5xdipIjRrp",
+"DEBUG": "example:*,test",
 },
 }

package.json

@@ -79,7 +79,6 @@
 },
 "patchedDependencies": {
 "@cloudflare/component-listbox@1.10.6": "patches/@cloudflare__component-listbox@1.10.6.patch",
-"debug@4.4.1": "patches/debug@4.4.1.patch",
 "pg@8.11.3": "patches/pg@8.11.3.patch",
 "toucan-js@3.3.1": "patches/toucan-js@3.3.1.patch",
 "toucan-js@4.0.0": "patches/toucan-js@4.0.0.patch",

packages/unenv-preset/build.config.ts

@@ -4,22 +4,9 @@ export default defineBuildConfig({
 declaration: true,
 rollup: {
 cjsBridge: true,
-inlineDependencies: true,
-resolve: {
-exportConditions: ["workerd"],
-},
 },
-externals: [/^cloudflare:/],
 entries: [
 "src/index",
-// Use rollup for debug file to inline the dependency
-"src/runtime/npm/debug",
-// Use mkdist for the rest to preserve structure
-{
-input: "src/runtime/",
-outDir: "dist/runtime",
-format: "esm",
-pattern: ["**", "!npm/debug.ts"],
-},
+{ input: "src/runtime/", outDir: "dist/runtime", format: "esm" },
 ],
 });

packages/unenv-preset/package.json

@@ -43,9 +43,7 @@
 "check:type": "tsc --noEmit"
 },
 "devDependencies": {
-"@types/debug": "4.1.12",
 "@types/node-unenv": "npm:@types/node@^22.14.0",
-"debug": "4.4.1",
 "typescript": "catalog:default",
 "unbuild": "^3.2.0"
 },

packages/unenv-preset/src/preset.ts

@@ -110,9 +110,6 @@ export function getCloudflarePreset({
 [`node:${m}`, `@cloudflare/unenv-preset/node/${m}`],
 ])
 ),
-
-// To override the npm shim from unenv
-debug: "@cloudflare/unenv-preset/npm/debug",
 },
 inject: {
 // Setting symbols implemented by workerd to `false` so that `inject`s defined in base presets are not used.