Support uv package manager for Python functions

[janisto]

Cloud Run added 3.14 support in December 2025:
https://docs.cloud.google.com/run/docs/release-notes
https://docs.cloud.google.com/run/docs/runtimes/python

uv is also now preferred way with 3.14.

[REQUIRED] Environment info

firebase-tools: 15.14.0

Platform: macOS

[REQUIRED] Test case

firebase.json with python314 runtime:

{
  "functions": [
    {
      "source": "functions",
      "location": "europe-west4",
      "codebase": "default",
      "runtime": "python314"
    }
  ],
}

[REQUIRED] Steps to reproduce

firebase deploy --only functions

[REQUIRED] Expected behavior

functions deployment works, including support for uv.

[REQUIRED] Actual behavior

> firebase deploy --only functions

=== Deploying to 'redacted'...

i  deploying functions
i  functions: preparing codebase default for deployment
i  functions: ensuring required API cloudfunctions.googleapis.com is enabled...
i  functions: ensuring required API cloudbuild.googleapis.com is enabled...
i  artifactregistry: ensuring required API artifactregistry.googleapis.com is enabled...

Error: Functions codebase default has invalid runtime python314 specified in firebase.json. Valid values are: 
- nodejs20
- nodejs22
- nodejs24
- python310
- python311
- python312
- python313
- dart3

[aalej]

Thanks for the report and for sharing your feedback @janisto! Looking up the uv package manager, it does sound like a good idea to have this, although it would take some time and require integration testing to ensure this works smoothly in firebase-tools. For now, I'll mark this as a feature request, for those who are interested in this, please leave a thumbs up on the original post or a comment.

Adding support for Python 3.14 to match the current available runtimes is something we should do, will raise this to our engineering team.