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authorAleksey Kladov <[email protected]>2020-12-03 15:08:27 +0000
committerAleksey Kladov <[email protected]>2020-12-03 15:08:27 +0000
commit3e00bfce2b1f53b14ec89ddb249364eac23f5b1e (patch)
treeedcfa6a87f28731c85317bb977c526f4c0e92585 /docs
parent5a1306a43652d914035b2cf0b703f4bfd3451a33 (diff)
Document statelessness invariant
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@@ -170,6 +170,22 @@ In general, API is centered around UI concerns -- the result of the call is what
170The results are 100% Rust specific though. 170The results are 100% Rust specific though.
171Shout outs to LSP developers for popularizing the idea that "UI" is a good place to draw a boundary at. 171Shout outs to LSP developers for popularizing the idea that "UI" is a good place to draw a boundary at.
172 172
173## LSP is sateless
174
175The protocol is implemented in the mostly stateless way.
176A good mental model is HTTP, which doesn't store per-client state, and instead relies on devices like cookies to maintain an illusion of state.
177If some action requires multi-step protocol, each step should be self-contained.
178
179A good example here is code action resolving process.
180TO display the lightbulb, we compute the list of code actions without computing edits.
181Figuring out the edit is done in a separate `codeAction/resolve` call.
182Rather than storing some `lazy_edit: Box<dyn FnOnce() -> Edit>` somewhere, we use a string ID of action to re-compute the list of actions during the resolve process.
183(See [this post](https://rust-analyzer.github.io/blog/2020/09/28/how-to-make-a-light-bulb.html) for more details.)
184The benefit here is that, generally speaking, the state of the world might change between `codeAction` and `codeAction` resolve requests, so any closure we store might become invalid.
185
186While we don't currently implement any complicated refactors with complex GUI, I imagine we'd use the same techniques for refactors.
187After clicking each "Next" button during refactor, the client would send all the info which server needs to re-recreate the context from scratch.
188
173## CI 189## CI
174 190
175CI does not test rust-analyzer, CI is a core part of rust-analyzer, and is maintained with above average standard of quality. 191CI does not test rust-analyzer, CI is a core part of rust-analyzer, and is maintained with above average standard of quality.