DEP0040 punycode deprecation warning still appears during deploy on firebase-tools 15.15.0 with Node.js 22

[ivenprillwitz]

[REQUIRED] Environment info

• firebase-tools: 15.15.0
• Node.js: v22.22.1
• npm: 10.9.4
• Platform: macOS 26.4.1 (arm64)

[REQUIRED] Test case

Running a real Firebase deploy for a TypeScript Cloud Functions project still prints:

(node:82935) [DEP0040] DeprecationWarning: The `punycode` module is deprecated. Please use a userland alternative instead.

[REQUIRED] Steps to reproduce

1. Install firebase-tools@15.15.0
2. Use Node.js 22.22.1
3. In a Firebase project with Cloud Functions configured, run a deploy such as:

firebase deploy --only functions

In my case the project has standard predeploy hooks for functions:

"predeploy": [
  "npm --prefix \"$RESOURCE_DIR\" run lint",
  "npm --prefix \"$RESOURCE_DIR\" run build"
]

[REQUIRED] Expected behavior

No DEP0040 warning should be printed during deploy on a current firebase-tools release.

[REQUIRED] Actual behavior

The deploy prints the punycode deprecation warning under Node.js 22.

Additional notes

• I upgraded specifically to check whether this was already fixed in a newer CLI release, but it still appears on 15.15.0.
• In the same environment, these commands do not print the warning:
  • firebase --version
  • firebase deploy --help
  • local function lint / build commands
• That makes it look like the warning is coming from a dependency that is only loaded on the actual deploy path.
• I found the older closed report here: punycode deprecation #7476. This new report is to note that the warning still appears on firebase-tools 15.15.0 with Node.js 22.22.1.

If helpful, I can provide a minimal reproduction repository as a follow-up.

[aalej]

Hey @ivenprillwitz, thanks for the thorough report, I appreciate this! I was able to reproduce getting the warning message. I think we tried to fix this issue in the past, maybe we missed something here. I'll raise this to our engineering team. Sharing mcve here - https://github.com/aalej/issues-10385

One thing to note, it does not seem to be reproducible on Node.js v24