The main aider leaderboard includes gemini models. I benchmarked gemma-2-27b-it, but it did so badly that it wasn't worth adding to the leaderboard.
can-ai-code seems to have Gemma 2-27b as pretty capable - beating out some of the other models that perform really well on aider: https://huggingface.co/spaces/mike-ravkine/can-ai-code-resul...
> LLMs which are good at editing code, not just good at writing code
So it may be that Gemma can write new code, but is not particularly good at editing or refactoring code.