Checking for additional_chat_templates doesn't work without internet (ConnectionError)

[akug]

System Info

• transformers version: 4.55.0.dev0
• Platform: Linux-6.6.87.2-microsoft-standard-WSL2-x86_64-with-glibc2.35
• Python version: 3.10.12
• Huggingface_hub version: 0.34.3
• Safetensors version: 0.5.3
• Accelerate version: 1.9.0
• Accelerate config: not found
• DeepSpeed version: not installed
• PyTorch version (accelerator?): 2.7.1+cu126 (NA)
• Tensorflow version (GPU?): not installed (NA)
• Flax version (CPU?/GPU?/TPU?): not installed (NA)
• Jax version: not installed
• JaxLib version: not installed
• Using distributed or parallel set-up in script?:

Who can help?

No response

Information

• The official example scripts
• My own modified scripts

Tasks

• An officially supported task in the examples folder (such as GLUE/SQuAD, ...)
• My own task or dataset (give details below)

Reproduction

This bug only occurs in the following scenario:

1. The user uses a model that uses a tokenizer that can have additional_chat_templates
2. The user runs the code without internet connection
3. The user did NOT set HF_HUB_OFFLINE=1, so offline mode is not enabled.

One example is running the train_dreambooth_lora_sdxl.py script without any adaptations, like this:

1. Download the SDXL model files and the vae model files into the cache
2. Turn off internet
3. Check that HF_HUB_OFFLINE is unset
4. Run the script

The error signature:

requests.exceptions.ConnectionError: (MaxRetryError('HTTPSConnectionPool(...): Max retries exceeded with url: /api/models/stabilityai/stable-diffusion-xl-base-1.0/tree/main/additional_chat_templates?recursive=False&expand=False (Caused by ...)))

Expected behavior

The script works without issues, because all files exist in the cache.