feat: support redirection by drbh · Pull Request #293 · huggingface/kernels

drbh · 2026-02-19T18:14:34Z

This PR adds a concept of redirection via a REDIRECT.toml file on the main branch.

The kernel tool will now first check for a redirection file, read and apply the redirection if it exists. The core use case is enable a way to manually redirect users from old repos to newer kernel repos with a custom message.

Note: redirections are single hop only, its not possible to redirect to another redirect

example file

destination = "kernels-community/activation"
message = "This kernel has been moved to kernels-community/activation. Please update your dependencies to use the new location."

this example file is currently hosted https://huggingface.co/drbh/test-kernel-redirect

HuggingFaceDocBuilderDev · 2026-02-19T18:16:33Z

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

danieldk

Really useful functionality! I would make it more general though, because as it is now, we would have to deprecate this again if we add archived/deprecation in the future.

danieldk · 2026-02-20T13:13:54Z

kernels/src/kernels/redirect.py

+
+from kernels.compat import tomllib
+
+REDIRECT_FILENAME = "REDIRECT.toml"


I think we should have a more generic name than that, so that we can use the same file for multiple signaling purposes.

Maybe kernel-status.toml?

good point, updated in latest and renamed the file to status rather than redirect

danieldk · 2026-02-20T13:14:29Z

kernels/src/kernels/redirect.py

+@dataclass
+class RedirectInfo:
+    destination: str
+    message: str


Redirect should be one of a union (so that we can also have e.g. deprecated/unmaintained in the future).

this makes sense, I've updated in latest for the following

@dataclass class Redirect: kind: str # must be "redirect" destination: str revision: str ...

danieldk · 2026-02-20T13:20:05Z

kernels/src/kernels/redirect.py

+    message: str
+
+
+def parse_redirect_file(content: str) -> RedirectInfo:


I think we should have this similar to https://github.com/huggingface/kernels/blob/main/kernels/src/kernels/metadata.py where these are methods.

Maybe we should consider switching to pydantic for these deserialization/ validation purposes.

good point, I've updated to follow a pattern like metadata, and added a kind key so we know which type to deserialize the file to.

pydantic could be nice to add, however i've left that out of this PR and can be followed up in the future to clean things up

danieldk · 2026-02-20T13:21:07Z

kernels/src/kernels/redirect.py

+    RED_COLOR = "\033[91m"
+    RESET_COLOR = "\033[0m"
+    msg = f"\n{RED_COLOR}{msg}{RESET_COLOR}"


Do these work well in Windows shells, I vaguely remember ASCII sequences giving issues and you need a library to make them work on *nix and Windows.

hmm I did a bit of research and I think they should work on any windows version >=10 however I've removed for now to simplify

danieldk · 2026-02-20T13:21:58Z

kernels/src/kernels/redirect.py

+    if "@" in redirect.destination:
+        return redirect.destination.rsplit("@", 1)
+    return redirect.destination, "main"


@ in the string data seems very ad-hoc if we have a structured data format like TOML?

good point, revision is now explicitly on the Redirect class now

danieldk · 2026-02-20T13:23:30Z

kernels/src/kernels/utils.py

    backend: str | None = None,
    variant_locks: dict[str, VariantLock] | None = None,
    user_agent: str | dict | None = None,
+    follow_redirects: bool = True,


I would leave this out. We already have plenty of arguments and we are probably going to add framework soon. I think we should just go for doing the right thing by default. If a kernel developer sets a repo to redirect, they probably really want to redirect.

agreed, updated in latest

danieldk · 2026-02-20T13:24:30Z

kernels/src/kernels/redirect.py

+@dataclass
+class RedirectInfo:
+    destination: str
+    message: str


I would leave out a message for now.

updated in latest

danieldk

Looks great!

feat: support redirection

37d2cd7

danieldk reviewed Feb 20, 2026

View reviewed changes

fix: prefer status

84f76de

drbh temporarily deployed to testpypi February 25, 2026 16:43 — with GitHub Actions Inactive

fix: typo fixes

dbc65a9

drbh temporarily deployed to testpypi February 25, 2026 17:08 — with GitHub Actions Inactive

fix: adjust for mypy

6692caf

drbh temporarily deployed to testpypi February 25, 2026 20:08 — with GitHub Actions Inactive

danieldk approved these changes Mar 2, 2026

View reviewed changes

drbh merged commit 74a19b0 into main Mar 2, 2026
48 of 54 checks passed


		from kernels.compat import tomllib

		REDIRECT_FILENAME = "REDIRECT.toml"

		message: str


		def parse_redirect_file(content: str) -> RedirectInfo:

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drbh commented Feb 19, 2026

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HuggingFaceDocBuilderDev commented Feb 19, 2026

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drbh Feb 25, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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drbh Feb 25, 2026 •

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