## Summary
Fixes#10588.
Most diagnostics from `ruff server` now appear as a much less alarming
warning instead of an error. Three diagnostics still appear as errors:
`F821` (`undefined name <name>`), `E902` (`IOError`) and `E999`
(`SyntaxError`).
## Test Plan
With an extension using the path to a locally-built executable, open a
file with multiple highlighted problems. Toggle the `Experimental
Server` setting on and off. The highlights should stay as warnings.
Then, modify the file to have a syntactically incorrect element. The
start of the invalid syntax should now have a red highlight.
## Summary
Fixes#10618.
This PR introduces a proper API for sending requests to the client and
handling any response sent back. Dynamic capability registration now
uses this new API, fixing an issue where a much more simplistic response
handler silently flushes a code action request that needed a response.
## Test Plan
#10618 can no longer be reproduced. No errors about unhandled responses
should appear in the extension output, and you should see this new log
when the server starts:
```
<DATE> <TIME> [info] <DURATION> INFO ruff_server::server Configuration file watcher successfully registered
```
## Summary
Fixes#10366.
`ruff server` now registers a file watcher on the client side using the
LSP protocol, and listen for events on configuration files. On such an
event, it reloads the configuration in the 'nearest' workspace to the
file that was changed.
## Test Plan
N/A
## Summary
Fixes#10324
This removes an overeager failure case where we would exit early if no
root directory or workspace folders were provided on server
initialization. We now fall-back to the current working directory as a
workspace for that file.
## Test Plan
N/A
## Summary
I used `codespell` and `gramma` to identify mispellings and grammar
errors throughout the codebase and fixed them. I tried not to make any
controversial changes, but feel free to revert as you see fit.
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## Summary
This PR introduces the `ruff_server` crate and a new `ruff server`
command. `ruff_server` is a re-implementation of
[`ruff-lsp`](https://github.com/astral-sh/ruff-lsp), written entirely in
Rust. It brings significant performance improvements, much tighter
integration with Ruff, a foundation for supporting entirely new language
server features, and more!
This PR is an early version of `ruff_lsp` that we're calling the
**pre-release** version. Anyone is more than welcome to use it and
submit bug reports for any issues they encounter - we'll have some
documentation on how to set it up with a few common editors, and we'll
also provide a pre-release VSCode extension for those interested.
This pre-release version supports:
- **Diagnostics for `.py` files**
- **Quick fixes**
- **Full-file formatting**
- **Range formatting**
- **Multiple workspace folders**
- **Automatic linter/formatter configuration** - taken from any
`pyproject.toml` files in the workspace.
Many thanks to @MichaReiser for his [proof-of-concept
work](https://github.com/astral-sh/ruff/pull/7262), which was important
groundwork for making this PR possible.
## Architectural Decisions
I've made an executive choice to go with `lsp-server` as a base
framework for the LSP, in favor of `tower-lsp`. There were several
reasons for this:
1. I would like to avoid `async` in our implementation. LSPs are mostly
computationally bound rather than I/O bound, and `async` adds a lot of
complexity to the API, while also making harder to reason about
execution order. This leads into the second reason, which is...
2. Any handlers that mutate state should be blocking and run in the
event loop, and the state should be lock-free. This is the approach that
`rust-analyzer` uses (also with the `lsp-server`/`lsp-types` crates as a
framework), and it gives us assurances about data mutation and execution
order. `tower-lsp` doesn't support this, which has caused some
[issues](https://github.com/ebkalderon/tower-lsp/issues/284) around data
races and out-of-order handler execution.
3. In general, I think it makes sense to have tight control over
scheduling and the specifics of our implementation, in exchange for a
slightly higher up-front cost of writing it ourselves. We'll be able to
fine-tune it to our needs and support future LSP features without
depending on an upstream maintainer.
## Test Plan
The pre-release of `ruff_server` will have snapshot tests for common
document editing scenarios. An expanded test suite is on the roadmap for
future version of `ruff_server`.
