RFC: Custom LSP Integration

[zbirenbaum]

So my custom copilot-lsp implementation https://github.com/zbirenbaum/copilot-rs finally seems to be in a pretty decent state and can now be used as a drop in replacement excluding panel completions (barely work in the official release anyways), which means its time to start considering integration here. This is mostly an RFC post regarding a couple of things:

How should we handle distribution of the alternative LSP?

We could distribute an equivalent agent.js using wasm bindings but there are two points for consideration:

• Since copilot-rs does not implement telemetry it is very possibly going to get shutdown
• We should avoid any backlash on copilot.lua if copilot-rs gets shut down

How should we handle feature integration?

The goal of developing an alternative LSP client has always been to achieve (at least) the following:

• Allow for VSCode only features such as copilot chat, which are trivial to implement on the LSP side and just involve sending off a custom prompt Support for copilot chat? #172
• Allow for increased customization of parameters exposed by the actual github copilot api endpoint (it's literally an OpenAI endpoint, just check their docs) such as number of completions, tokens, etc...
• Allow for integration of other models such as LLAMA by setting up middleware Copilot is about to start charging. #38
• Make support for features like workspaces clear and documented A question. Does copilot.lua expose the project or open tabs to copilot? #171

Since these features will eventually be present in copilot-rs, but not the official agent.js, client side support becomes a bit more complicated

@MunifTanjim would love to hear your thoughts. I'm leaning towards creating a new fork of copilot.lua just to support and redistribute copilot-rs and putting a note about it in the README. It's not ideal since requiring a whole different plug-in will slow testing and adoption dramatically, but at least it would keep the api clean and this plug-in protected from any potential backlash.

If anyone has input or knows of any projects that successfully navigated the telemetry problem please feel free to comment and discuss here.

[MunifTanjim]

Even if it's included in this repo, it should be somewhat separated (either opt-in or opt-out) from the current implementation that mimics everything from https://github.com/github/copilot.vim. Then the user can choose which implementation to use.

[zbirenbaum]

Even if it's included in this repo, it should be somewhat separated (either opt-in or opt-out) from the current implementation that mimics everything from https://github.com/github/copilot.vim. Then the user can choose which implementation to use.

Yeah this was what I was thinking. I'm really hesitant to put it in this repo at all though unless I can find some precedent to show it's remotely safe. It doesn't break any license terms but not sure that will matter.

[S1M0N38]

Official copilot LSP:
https://www.npmjs.com/package/@github/copilot-language-server