The image runs unslothai/notebooks unchanged by refusing a notebook's
transformers pin and activating a baked sidecar on sys.path instead. Selection
was a pure ceiling (smallest baked version >= the request) and ignored that vLLM
is version-locked to transformers, so two of the four baked sidecars could not be
imported by the baked vLLM 0.26.0 at all:
4.57.6 ImportError: Support for Transformers v4 is deprecated and was removed
in vLLM v0.24.0
5.3.0 ImportError: cannot import name 'ALLOWED_LAYER_TYPES' from
transformers.configuration_utils
Those two are exactly the ones the common pins select. 241 notebooks pin
4.48/4.52.3/4.55.4/4.56.1/4.56.2/4.57.x and land on the 4.57.6 sidecar, 13 pin
5.2.0/5.3.0 and land on the 5.3.0 sidecar. All 254 died at
`from unsloth import FastModel`, before the first model cell. Pointing
UNSLOTH_TF_SIDECAR_ROOT at an empty directory and changing nothing else turned
Gemma3 (270M) and Gemma3 (1B) GRPO into clean 22/22 and 25/25 passes.
Put a floor in front of the ceiling. Which versions clear the floor is measured,
not hardcoded: the build imports vllm.transformers_utils.config under every
candidate sidecar, deletes the ones that raise, and records the lowest survivor.
That is the vLLM module which reads the transformers API, it reproduces both
failures, and it imports without a GPU, which matters because the build host has
none. A request below the floor is clamped up to the lowest eligible sidecar,
the closest version to the notebook's pin this image can actually run; a request
above every sidecar still falls through to the baked transformers.
Measured on the rebuilt image: sidecars 5.5.0 and 5.10.2 survive, floor 5.5.0,
tf-sidecars drops from 250M to 123M, and all 13 distinct transformers pins found
across the 433 shipped notebooks now reach `from unsloth import FastModel`.
Gemma3 (270M) runs end to end exactly as shipped, 22 of 22 cells, loss 4.09 down
to 0.85 over 10 steps.
