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v5.4.0 breaks PretrainedConfig type checking #45071
Description
System Info
transformers 5.4.0
mypy 1.19.1
python 3.10
Who can help?
No response
Information
- The official example scripts
- My own modified scripts
Tasks
- An officially supported task in the
examplesfolder (such as GLUE/SQuAD, ...) - My own task or dataset (give details below)
Reproduction
# transformers_typing.py
from transformers import LlamaConfig
llama_config = LlamaConfig(vocab_size=32000)Run mypy type checker
mypy transformers_typing.pyOutput:
transformers_typing.py:3: error: Unexpected keyword argument "vocab_size" for "LlamaConfig" [call-arg]
Found 1 error in 1 file (checked 1 source file)
Note: It's not just vocab_size that's missing. As far as I can tell, this fails with all config attributes.
Expected behavior
Type checking passes. Note: this is the case for transformers<5.4.0.
Activity
Cap transformers at `<5.4.0` (#372)
Rocketknight1 commentedon Apr 2, 2026
We don't guarantee
mypycompatibility unfortunately! If someone can find a clean fix that restores it, we might merge that PR, but we don't want to add a lot of code complexity to do itfix: restore mypy type checking for PreTrainedConfig subclasses (hugg…
fix: restore mypy type checking for PreTrainedConfig subclasses (hugg…
shhKnight30 commentedon Apr 5, 2026
@Rocketknight1 please look at my PR once
zucchini-nlp commentedon Apr 9, 2026
@fynnsu hey, we'll merge the suggestion from @shhKnight30
We don't guarantee that mypy would work, indeed. Instead, we are slowly moving towards making transformers
ty-compatible, and I can confirm thattycomplains about the same thingsCap transformers at `<5.4.0` (vllm-project#372)
fix: restore mypy type checking for PreTrainedConfig subclasses (#45071…
fix: restore mypy type checking for PreTrainedConfig subclasses (hugg…