Suggestion to Upgrade the "clean" Option in buf.gen.yaml to Specify Explicit Paths

[nemo1105]

Feature

I've written a local buf plugin that generates empty Connect implementation files from .proto definitions. Whenever I define a new RPC method, I simply run the proto compilation again, and it automatically generates a corresponding empty implementation for the new RPC.

Currently, if I set clean: true, all previously generated RPC implementations are deleted and regenerated from scratch. However, I'd also like certain directories that contain basic structural definitions generated from proto—such as the protocol directory—to be cleaned on every compilation (e.g., in case I've deleted a .proto file and want its generated artifacts removed too).

It would be ideal if I could configure the clean option in buf.gen.yaml like this:

clean:
  - protocol

That would solve the problem perfectly. After all, when using protoc directly, it's quite straightforward to customize whether or not to delete files in the output directory. If buf aims to offer a superior developer experience, I’d suggest avoiding overly restrictive defaults and allowing more flexibility.

[emcfarlane]

Thanks for the report. We recently shipped "smart clean" in #4413 which changes how clean: true works: it no longer deletes the entire output directory upfront. Instead, it only removes stale files that weren't produced by the current generation run. This helps with the deleted .proto file scenario you mentioned.

However, you're right that clean is currently a global option that applies to all plugins. We don't support per-plugin clean configuration today. If you have a plugin that generates scaffolding you want to preserve alongside a plugin whose output should always be cleaned, there isn't a way to express that distinction in buf.gen.yaml right now.

We'll track this as a feature request for per-plugin clean support. In the meantime, one workaround is to use separate buf.gen.yaml files, one with clean: true for your protocol output, and one without for your implementation stubs, and run buf generate twice with --template.