The pip shim fronts pip/uv inside the notebook kernel so an install cell cannot
replace the baked cu128 stack, but _KEEP only covered torch/vLLM/unsloth. Across
the 433 shipped notebooks that left the training half wide open:
trl 382 pin an older release, 378 of them ending the install cell with
`pip install --no-deps trl==0.22.2`, against a baked trl 0.24.0
torchao 273 reinstall it and 2 pin 0.15.0, replacing 0.17.0+cu128
torchcodec 92 reinstall it and 26 pin 0.5 or 0.7.0, replacing the
0.11.0+cu128 wheel the Dockerfile pairs with torch 2.11
datasets 254 reinstall it, observed falling from 4.3.0 to 3.0.0
peft 225 reinstall it, observed falling from 0.19.1 to 0.14.0
accelerate 225 reinstall it
hf hub 240 reinstall it and tokenizers 64, both version-locked to
transformers and shipped in matched copies inside every sidecar
So every notebook run mutated the stack the image was validated with, while the
shim printed that it was keeping the baked versions.
The membership criterion is "replacing this invalidates the tested stack or
breaks unsloth", not "a notebook mentions it": snac, causal-conv1d, mamba-ssm,
omegaconf, protobuf, sentencepiece and the rest still install normally.
Verified in the rebuilt image by running the Gemma3 (270M) install cell verbatim:
trl 0.24.0, peft 0.19.1, datasets 4.3.0, accelerate 1.14.0, torchao 0.17.0+cu128,
transformers 5.14.1 and huggingface_hub 1.24.0 are all unchanged afterwards, the
requested transformers pin is still recorded for the sidecar, and a package the
image does not bake still installs.
The existing shim tests used peft as their "unprotected package" sentinel, so
they move to snac.
