Gemma 4 support via `transformers==5.5`

[jamesbraza]

#1426 recently pulled in transformers v5 support for up to version 5.3.0.

https://github.com/huggingface/transformers/releases/tag/v5.5.0 just added Gemma 4 support in transformers v5.5.0.

The request is, can SkyRL pull in transformers v5.5 to support Gemma 4?

[erictang000]

hey @jamesbraza, looking into adding a script for this, will keep you posted!

[jamesbraza]

Looks like vllm==0.19.1 just pulled in transformers v5 support in vllm-project/vllm#30566.

However, vllm pinned transformers==5.5.3, which is incompatible with SkyRL's current upper pin of v5.3.

So this issue is now double-duty, both compatibility for Gemma. 4 and latest vllm.

[ArthurZucker]

Happy to help if there's anything we can do to help, IDK where the blockers are, is it on processor refacto? 🤗

[jamesbraza]

Hi team please see #1561, it should handle the upgrade. I ran the GPU tests manually on my company's cluster.

@ArthurZucker if you want you can see what it took.

[erictang000]

thanks @jamesbraza, sorry for the delay on my end, will take a look at your PR!

[erictang000]

hey @jamesbraza - just confirming - is merging #1561 just a pre-req for gemma support? And it's actually also blocked by #1559 and #1564?

For context I also tried working on getting this working but was seeing garbled outputs after weight sync for the colocated case: #1576, perhaps related to #1559.

[jamesbraza]

hey @jamesbraza - just confirming - is merging #1561 just a pre-req for gemma support?

Yes, we need latest transformers. You're right, you can view that PR as a prereq for Gemma 4 (but unfortunately there's other work needed).

And it's actually also blocked by #1559 and #1564?

I was able to work around those two locally in my own repository using patches.

Though I eventually hit huggingface/transformers#45663 and threw in the towel on Gemma 4 for now.

It would be good to merge in #1561, as it modernizing vllm and transformers unblocks dependency resolution on my side.