Save model config in Trainer checkpoints for non-PreTrainedModel models#45055
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vasanthrpjan1-boop wants to merge 1 commit intohuggingface:mainfrom
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Save model config in Trainer checkpoints for non-PreTrainedModel models#45055vasanthrpjan1-boop wants to merge 1 commit intohuggingface:mainfrom
vasanthrpjan1-boop wants to merge 1 commit intohuggingface:mainfrom
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When the model is not a `PreTrainedModel`, Trainer only saves the state dict but not the model config. This means `from_pretrained(ckpt_path)` fails because there is no `config.json` in the checkpoint directory. Save `config.json` alongside the state dict when the model has a config attribute, enabling argumentless loading from Trainer checkpoints. Fixes huggingface#44450 Made-with: Cursor
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Apr 28, 2026
Direct merge conflicted after Trainer refactors; applied the minimal config-saving change from 57cb2b9.
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What does this PR do?
When
Trainersaves a checkpoint for a model that is not aPreTrainedModel(e.g. a customnn.Module), it only saves the state dict but not the model config. This meansModel.from_pretrained(ckpt_path)requires the caller to pass all the original init arguments again, which is inconvenient.This PR saves the model's
config.jsonin the checkpoint directory when the model has aconfigattribute, even when it falls through to the state-dict-only saving path. This enables argumentless loading from Trainer checkpoints:The change is a 3-line addition in
Trainer._save()that callsconfig.save_pretrained(output_dir)on the unwrapped model's config when available. This does not affect the existingPreTrainedModelpath, which already saves config viasave_pretrained().Fixes #44450