[infusini]

What

MinimalDataset was the only concrete builder without a @deprecated marker, so it was the one path a caller could still adopt without any warning. It has one now.

The four existing messages said a builder "may be removed in a future release" without naming a replacement, which tells a caller to stop but not where to go. All of them now point at the same thing:

Build a Dataset directly and pass it to client.datasets.create(): Dataset(input_dataset_ids=..., name=..., job_slug=..., job_run_params=...). The job's own parameter schema is available from client.jobs.list().

That is the reason the builders are going in the first place. Each one duplicates a job's parameter schema in Python, so it drifts whenever the job changes server-side, while client.jobs.list() is the live schema.

Why BaseDatasetBuilder is left undecorated

@deprecated on an ABC fires at class-definition time, not on use. Decorating the base would emit a warning for every subclass as soon as md_python is imported, including for callers that never touch a builder. Verified:

>>> Child(x=1)
<frozen abc>:106: DeprecationWarning: Base is deprecated   # at definition, not here

Its docstring carries the note instead, and test_importing_md_python_does_not_warn pins the import-time silence so the decorator cannot be added later without a test failing.

Tests

Two added. One asserts every concrete builder warns and that the message names client.datasets.create(), so a future builder cannot be added with a dead-end message. The other pins import-time silence.

317 passed. black, isort and mypy all clean across the repo, not just the changed files.

Risk

Behavioural change is limited to a DeprecationWarning on MinimalDataset, which is hidden by default in Python and visible under -W or pytest. No signature, no return value and no wire format changes.