Functions emulator does not work with yarn configured with pnpm nodeLinker

[blikblum]

[REQUIRED] Environment info

firebase-tools: 15.24.0

Platform: Ubuntu

[REQUIRED] Test case

The repository below contains a minimal firebase functions setup in a yarn with pnpm nodeLinker setup

Clone, execute yarn, cd functions, yarn serve

https://github.com/blikblum/firebase-functions-yarn

[REQUIRED] Steps to reproduce

• Init a yarn package
• Configure nodeLinker to pnpn
• Run firebase init configuring functions (vanilla javascript) and functions emulator
• Run yarn install
• Run cd functions
• Run yarn serve

[REQUIRED] Expected behavior

The functions emulator should start without errors

[REQUIRED] Actual behavior

yarn serve fails with error "Failed to load function definition from source: FirebaseError: Failed to find location of Firebase Functions SDK. Please file a bug on Github (https://github.com/firebase/firebase-tools/)."

[2026-07-18T13:00:20.859Z] ----------------------------------------------------------------------
[2026-07-18T13:00:20.860Z] Command: /home/luiz/.nvm/versions/node/v24.12.0/bin/node /home/luiz/.nvm/versions/node/v24.12.0/bin/firebase emulators:start --only functions --debug
[2026-07-18T13:00:20.861Z] CLI Version: 15.24.0
[2026-07-18T13:00:20.861Z] Platform: linux
[2026-07-18T13:00:20.861Z] Node Version: v24.12.0
[2026-07-18T13:00:20.861Z] Detected Agent: unknown
[2026-07-18T13:00:20.861Z] Time: Sat Jul 18 2026 10:00:20 GMT-0300 (Horário Padrão de Brasília)
[2026-07-18T13:00:20.861Z] ----------------------------------------------------------------------

[2026-07-18T13:00:21.279Z] > command requires scopes: ["email","openid","https://www.googleapis.com/auth/cloudplatformprojects.readonly","https://www.googleapis.com/auth/firebase","https://www.googleapis.com/auth/cloud-platform"]
[2026-07-18T13:00:21.279Z] > authorizing via signed-in user
i emulators: Starting emulators: functions {"metadata":{"emulator":{"name":"hub"},"message":"Starting emulators: functions"}}
i emulators: Detected demo project ID "demo-no-project", emulated services will use a demo configuration and attempts to access non-emulated services for this project will fail. {"metadata":{"emulator":{"name":"hub"},"message":"Detected demo project ID "demo-no-project", emulated services will use a demo configuration and attempts to access non-emulated services for this project will fail."}}
[2026-07-18T13:00:21.282Z] [logging] Logging Emulator only supports listening on one address (127.0.0.1). Not listening on ::1
[2026-07-18T13:00:21.282Z] assigned listening specs for emulators {"user":{"hub":[{"address":"127.0.0.1","family":"IPv4","port":4400},{"address":"::1","family":"IPv6","port":4400}],"ui":[{"address":"127.0.0.1","family":"IPv4","port":4000},{"address":"::1","family":"IPv6","port":4000}],"logging":[{"address":"127.0.0.1","family":"IPv4","port":4500}]},"metadata":{"message":"assigned listening specs for emulators"}}
[2026-07-18T13:00:21.285Z] Write emulator hub locator at /tmp/hub-demo-no-project.json
[2026-07-18T13:00:21.288Z] [functions] Functions Emulator only supports listening on one address (127.0.0.1). Not listening on ::1
[2026-07-18T13:00:21.288Z] [eventarc] Eventarc Emulator only supports listening on one address (127.0.0.1). Not listening on ::1
[2026-07-18T13:00:21.288Z] [tasks] Cloud Tasks Emulator only supports listening on one address (127.0.0.1). Not listening on ::1
[2026-07-18T13:00:21.289Z] late-assigned ports for functions and eventarc emulators {"user":{"hub":[{"address":"127.0.0.1","family":"IPv4","port":4400},{"address":"::1","family":"IPv6","port":4400}],"ui":[{"address":"127.0.0.1","family":"IPv4","port":4000},{"address":"::1","family":"IPv6","port":4000}],"logging":[{"address":"127.0.0.1","family":"IPv4","port":4500}],"functions":[{"address":"127.0.0.1","family":"IPv4","port":5001}],"eventarc":[{"address":"127.0.0.1","family":"IPv4","port":9299}],"tasks":[{"address":"127.0.0.1","family":"IPv4","port":9499}]},"metadata":{"message":"late-assigned ports for functions and eventarc emulators"}}
[2026-07-18T13:00:21.297Z] defaultcredentials: writing to file /home/luiz/.config/firebase/XXX_gmail.com_application_default_credentials.json
[2026-07-18T13:00:21.298Z] Setting GAC to /home/luiz/.config/firebase/XXX_gmail.com_application_default_credentials.json {"metadata":{"emulator":{"name":"functions"},"message":"Setting GAC to /home/luiz/.config/firebase/XXX_gmail.com_application_default_credentials.json"}}
i functions: Watching "/home/luiz/repositories/firebase-functions-yarn/functions" for Cloud Functions... {"metadata":{"emulator":{"name":"functions"},"message":"Watching "/home/luiz/repositories/firebase-functions-yarn/functions" for Cloud Functions..."}}
[2026-07-18T13:00:21.307Z] Validating nodejs source
[2026-07-18T13:00:21.643Z] > [functions] package.json contents: {
"name": "functions",
"description": "Cloud Functions for Firebase",
"scripts": {
"serve": "firebase emulators:start --only functions",
"shell": "firebase functions:shell",
"start": "npm run shell",
"deploy": "firebase deploy --only functions",
"logs": "firebase functions:log"
},
"engines": {
"node": "24"
},
"main": "index.js",
"dependencies": {
"firebase-admin": "^13.6.0",
"firebase-functions": "^7.0.0"
},
"devDependencies": {
"firebase-functions-test": "^3.4.1"
},
"private": true
}
[2026-07-18T13:00:21.643Z] Building nodejs source
[2026-07-18T13:00:21.643Z] Failed to find version of module node: reached end of search path /home/luiz/repositories/firebase-functions-yarn/functions/node_modules
✔ functions: Using node@24 from host.
[2026-07-18T13:00:21.645Z] Could not find functions.yaml. Must use http discovery
⬢ functions: Failed to load function definition from source: FirebaseError: Failed to find location of Firebase Functions SDK. Please file a bug on Github (https://github.com/firebase/firebase-tools/). {"metadata":{"emulator":{"name":"functions"},"message":"Failed to load function definition from source: FirebaseError: Failed to find location of Firebase Functions SDK. Please file a bug on Github (https://github.com/firebase/firebase-tools/)."}}
[2026-07-18T13:00:21.653Z] Could not find VSCode notification endpoint: TypeError: fetch failed. If you are not running the Firebase SQL Connect VSCode extension, this is expected and not an issue.

┌─────────────────────────────────────────────────────────────┐
│ ✔ All emulators ready! It is now safe to connect your app. │
│ i View Emulator UI at http://127.0.0.1:4000/ │
└─────────────────────────────────────────────────────────────┘

┌───────────┬────────────────┬─────────────────────────────────┐
│ Emulator │ Host:Port │ View in Emulator UI │
├───────────┼────────────────┼─────────────────────────────────┤
│ Functions │ 127.0.0.1:5001 │ http://127.0.0.1:4000/functions │
└───────────┴────────────────┴─────────────────────────────────┘
Emulator Hub host: 127.0.0.1 port: 4400
Other reserved ports: 4500

[blikblum]

Yarn’s pnpm linker installs packages beneath node_modules/.store, while Firebase CLI searches conventional .bin locations and only handles native pnpm’s .pnpm layout. Yarn linker documentation, Firebase discovery implementation.

[aalej]

Thanks for the report @blikblum! I tried to clone the repository you shared, but it looks like the functions folder is missing from it. So I cloned it and ran firebase init to initialize a functions project. This reproduces the issue, but let me know in case I may have made a mistake with the setup - https://github.com/aalej/firebase-functions-yarn_10813

I think your observations are correct. With Yarn's nodeLinker set to pnpm, the packages are located in <project_root>/node_modules/.store/** so the Firebase CLI fails to find the firebase-functions bin since it looks for it in .bin/function -

firebase-tools/src/deploy/functions/runtimes/node/index.ts

Lines 182 to 199 in 48242c1

	const sourceNodeModulesPath = path.join(this.sourceDir, "node_modules");
	const projectNodeModulesPath = path.join(this.projectDir, "node_modules");
	const sdkPath = require.resolve("firebase-functions", { paths: [this.sourceDir] });
	const sdkNodeModulesPath = sdkPath.substring(0, sdkPath.lastIndexOf("node_modules") + 12);
	const ignorePnpmModulesPath = sdkNodeModulesPath.replace(/\/\.pnpm\/.*/, "");
	for (const nodeModulesPath of [
	sourceNodeModulesPath,
	projectNodeModulesPath,
	sdkNodeModulesPath,
	ignorePnpmModulesPath,
	]) {
	const binPath = path.join(nodeModulesPath, ".bin", "firebase-functions");
	if (fileExistsSync(binPath)) {
	logger.debug(`Found firebase-functions binary at '${binPath}'`);
	return binPath;
	}
	}

I'll raise this issue to our engineering team to see if we can support this behavior.

[blikblum]

sorry. i forgot to push. Done now.

Your setup shows the error accurately

[aalej]

quick update here: Discussed this with our engineering team, and we currently do not support using Yarn 2 with Firebase Functions. I'll mark this issue as a feature request. For those who are also interested in this, please leave a thumbs up on the original post to help us track the demand for this feature.