vocab_size missing in IndicTransConfig β breaking generation in latest Transformers
Hi AI4Bharat Team,
I'm using the ai4bharat/indictrans2-en-indic-1B model for a thesis project. Until recently, everything worked perfectly, both in local and Colab environments. However, after a recent update, the model is throwing the following error during generate():
AttributeError: 'IndicTransConfig' object has no attribute 'vocab_size'
This appears to be because vocab_size is missing in the current config.json, and Hugging Face's generate() relies on it during beam search. This breaks all downstream use of the model β even simple batch translations fail.
Steps Iβve tried:
- Patching config.jsonmanually (addingvocab_sizekey).
- Downgrading transformers+huggingface_hub.
- Trying old revisions (which now 404).
- Using both CPU and GPU environments β same issue.
This issue is critical for me as my final presentation is next week (I'm a final year student at Trinity College Dublin). Please advise if:
- An older working snapshot can be restored.
- The vocab_sizecan be reintroduced in config or handled in code.
Thanks again for the incredible work with IndicTrans2 β this model is genuinely important for bridging language barriers.
Best regards,
Aditya  
This has been resolved.

