fix: add ExperimentalFeatureWarning compat shim#2789
Merged
tempusfrangit merged 4 commits intomainfrom Mar 2, 2026
Merged
Conversation
tempusfrangit
requested review from
bfirsh,
Copilot,
markphelps and
michaeldwan
![github-code-quality[bot]](https://avatars.githubusercontent.com/u/9919?s=60&v=4){kind=small}
Contributor
There was a problem hiding this comment.
Pull request overview
Adds a backwards-compatible ExperimentalFeatureWarning export to the Python cog SDK so older models that import it (to suppress warnings) don’t fail with ImportError after the coglet migration.
Changes:
- Introduces a lazy
ExperimentalFeatureWarningcompat shim via module-level__getattr__. - Emits a deprecation notice directly to stderr when the deprecated symbol is accessed.
- Exposes the deprecated symbol via
__all__.
💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.
tempusfrangit
force-pushed
the
fix/experimental-feature-warning-compat
branch
from
ff8b338 to
f3156b0
Compare
markphelps
reviewed
Mar 2, 2026
Existing models import ExperimentalFeatureWarning to suppress warnings:
from cog import ExperimentalFeatureWarning
warnings.filterwarnings('ignore', category=ExperimentalFeatureWarning)
This class was removed when the Python HTTP server was replaced by
coglet, causing ImportError on model load.
The shim provides _ExperimentalFeatureWarning (a FutureWarning subclass)
via module-level __getattr__, which:
- Prints a deprecation notice to stderr (cannot be swallowed by
warnings.filterwarnings('ignore'))
- Caches in globals() so the message fires at most once
- Returns the class so existing filterwarnings() calls still work
Add Python unit tests verifying the __getattr__ compat shim works: import succeeds, deprecation prints to stderr once, is FutureWarning subclass, works with warnings.filterwarnings, unknown attrs raise. Add txtar integration test proving a predictor importing ExperimentalFeatureWarning builds and runs end-to-end. Also fix coglet wheel build/test workflow: - noxfile: fail loudly when dist/ has wheels but none match platform (was silently falling back to PyPI or installing wrong-platform wheel) - noxfile: always use editable install for SDK so tests run against working tree - mise.toml: remove sources/outputs caching from build:coglet:wheel (the broad glob falsely matched cross-compiled wheels, causing skips) - mise.toml: test:python depends on build:coglet:wheel so dist/ always has a native wheel
tempusfrangit
force-pushed
the
fix/experimental-feature-warning-compat
branch
from
f3156b0 to
5fa03f4
Compare
Editable install fails in CI because setuptools_scm needs a full git checkout. Use the pre-built wheel from dist/ when available, fall back to editable install only for local dev.
meatballhat-cf
approved these changes
Mar 2, 2026
Contributor
meatballhat-cf
left a comment
meatballhat-cf
left a comment
There was a problem hiding this comment.
Looks like we got some wheel-related fixes along the way, which is 🎉 but also it would be nice for future selves if the PR description mentioned it.
| return self.model.generate(prompt, image) | ||
| """ | ||
|
|
||
| import sys as _sys |
Contributor
There was a problem hiding this comment.
Why the _sys alias? To work around libraries that runtime patch stderr?
| # Metrics | ||
| "current_scope", | ||
| # Deprecated compat shims | ||
| "ExperimentalFeatureWarning", |
Contributor
There was a problem hiding this comment.
I think ExperimentalFeatureWarning should not be in the __all__ since it's not supposed to be part of the public API. I found maybe one legit case of from cog import * in GitHub, so I think we can safely say the backward compatibility only applies to named access.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
Existing models import
ExperimentalFeatureWarningfromcogto suppress experimental feature warnings. This was removed when the Python HTTP server was replaced by coglet (#2783), breaking those models at import time withImportError.What Changed
Added a backwards-compatible shim in
python/cog/__init__.pythat:ExperimentalFeatureWarningvia module__getattr__(lazy — only triggers when actually imported)warnings.filterwarnings("ignore")or any other warnings suppressionFutureWarningsubclass, so existingwarnings.filterwarnings("ignore", category=ExperimentalFeatureWarning)calls work syntacticallyModels affected
Any model that does:
Including
cog-examples/hello-concurrency,cog-examples/hello-context,cog-examples/hello-replicate.