🐽 Bacon Language Server 🐽
Are you tired of rust-analyzer diagnostics being slow?
LSP Server wrapper for the exceptional Bacon exposing textDocument/diagnostic and workspace/diagnostic capabilities.
bacon-ls 🐽 does not substitute rust-analyzer, it's a companion tool that can help with large
codebases where rust-analyzer can become slow dealing with diagnostics.
bacon-ls 🐽 does not help with completion, analysis, refactor, etc... For these, rust-analyzer must be running.
NOTE: bacon-ls 0.5+ has breaking changes and will work only with bacon 3.7+. The README for bacon-ls 0.4
can be found here.
See bacon-ls 🐽 blog post: https://lmno.lol/crisidev/bacon-language-server
bacon-ls 🐽 is meant to be easy to include in your IDE configuration.
Features
- Read diagnostics from produced by Bacon.
- Push diagnostics to the LSP client on certain events like saving or files changes.
- Precise diagnostics positions.
- Ability to react to changes over document saves and changes that can be configured.
- Replacement code actions as suggested by
clippy.
- Automatic validation of
bacon preferences to ensure bacon-ls can work with them.
- Start
bacon in background based on user preferences (requires bacon 3.8.0).
- Synchronize diagnostics for all open files.
Limitations
- Windows support is not tested and probably broken - #10
Installation
VSCode
First, install Bacon.
The VSCode extension is available on both VSCE and OVSX:
Mason.nvim
Both Bacon and Bacon-ls are installable via mason.nvim:
:MasonInstall bacon bacon-ls
Manual
First, install Bacon and bacon-ls 🐽
❯❯❯ cargo install --locked bacon bacon-ls
❯❯❯ bacon --version
bacon 3.8.0 # make sure you have at least 3.8.0
❯❯❯ bacon-ls --version
0.10.0 # make sure you have at least 0.10.0
Configuration
Configure Bacon export settings with bacon-ls 🐽 export format and proper span support in the bacon preference file.
To find where the file should be saved, you can use the command bacon --prefs:
[jobs.bacon-ls]
command = [ "cargo", "clippy", "--tests", "--all-targets", "--all-features", "--message-format", "json-diagnostic-rendered-ansi" ]
analyzer = "cargo_json"
need_stdout = true
[exports.cargo-json-spans]
auto = true
exporter = "analyzer"
line_format = "{diagnostic.level}|:|{span.file_name}|:|{span.line_start}|:|{span.line_end}|:|{span.column_start}|:|{span.column_end}|:|{diagnostic.message}|:|{span.suggested_replacement}"
path = ".bacon-locations"
NOTE: bacon MUST be running to generate the export locations with the bacon-ls job: bacon -j bacon-ls.
From bacon-ls 0.10.0, this is done automatically if the option runBaconInBackground is set to true.
The language server can be configured using the appropriate LSP protocol and
supports the following values:
locationsFile Bacon export filename (default: .bacon-locations).updateOnSave Try to update diagnostics every time the file is saved (default: true).updateOnSaveWaitMillis How many milliseconds to wait before updating diagnostics after a save (default: 1000).updateOnChange Try to update diagnostics every time the file changes (default: true).validateBaconPreferences: Try to validate that bacon preferences are setup correctly to work with bacon-ls (default: true).createBaconPreferencesFile: If no bacon preferences file is found, create a new preferences file with the bacon-ls job definition (default: true).runBaconInBackground: Run bacon in background for the bacon-ls job (default: true)runBaconInBackgroundCommandArguments: Command line arguments to pass to bacon running in background (default "--headless -j bacon-ls")synchronizeAllOpenFilesWaitMillis: How many milliseconds to wait between background diagnostics check to synchronize all open files (default: 2000).
Neovim - LazyVim
vim.g.lazyvim_rust_diagnostics = "bacon-ls"
Neovim - Manual
NeoVim requires nvim-lspconfig to be configured
and rust-analyzer diagnostics must be turned off for bacon-ls 🐽
to properly function.
bacon-ls is part of nvim-lspconfig from commit
6d2ae9f
and it can be configured like any other LSP server works best when
vim.diagnostics.opts.update_in_insert
is set to true.
require("lspconfig").bacon_ls.setup({
init_options = {
updateOnSave = true
updateOnSaveWaitMillis = 1000
updateOnChange = false
...
}
})
For rust-analyzer, these 2 options must be turned off:
rust-analyzer.checkOnSave.enable = false
rust-analyzer.diagnostics.enable = false
VSCode
The extension can be configured using the VSCode settings interface.
It is very important that rust-analyzer Check On Save and Diagnostics are turned off for bacon-ls to work properly:
- Untick
Rust-analyzer -> general -> Check On Save
- Untick
Rust-analyzer -> diagnostics -> Enable
Coc.nvim
call coc#config('languageserver', {
\ 'bacon-ls': {
\ 'command': '~/.cargo/bin/bacon-ls',
\ 'filetypes': ['rust'],
\ 'rootPatterns': ['.git/', 'Cargo.lock', 'Cargo.toml'],
\ 'initializationOptions': {
\ 'updateOnSave': v:true,
\ 'updateOnSaveWaitMillis': 1000,
\ 'updateOnChange': v:false
\ },
\ 'settings': {}
\ }
\ })
Helix
Extend your languages.toml with the following:
[[language]]
name = "rust"
language-servers = ["rust-analyzer", "bacon-ls"]
[language-server.rust-analyzer.config]
checkOnSave = { enable = false }
diagnostics = { enable = false }
[language-server.bacon-ls]
command = "bacon-ls"
Troubleshooting
bacon-ls 🐽 can produce a log file in the folder where its running by exporting the RUST_LOG variable in the shell:
Bacon preferences
If the bacon preference are not correct, an error message will be published to the LSP client, advising the user to
check the README.
Vim - Neovim
❯❯❯ export RUST_LOG=debug
❯❯❯ nvim src/some-file.rs # or vim src/some-file.rs
# the variable can also be exported for the current command and not for the whole shell
❯❯❯ RUST_LOG=debug nvim src/some-file.rs # or RUST_LOG=debug vim src/some-file.rs
❯❯❯ tail -F ./bacon-ls.log
VSCode
Enable debug logging in the extension options.
❯❯❯ tail -F ./bacon-ls.log
How does it work?
bacon-ls 🐽 reads the diagnostics location list generated
by Bacon's export-locations
and exposes them on STDIO over the LSP protocol to be consumed
by the client diagnostics.
It requires Bacon to be running alongside
to ensure regular updates of the export locations.
The LSP client reads them as response to textDocument/diagnostic and workspace/diagnostic.
Thanks
bacon-ls 🐽 has been inspired by typos-lsp.
Roadmap to 1.0 - ✅ done 🕖 in progress 🌍 future
- ✅ Implement LSP server interface for
textDocument/diagnostic and workspace/diagnostic
- ✅ Manual Neovim configuration
- ✅ Manual LazyVim configuration
- ✅ Automatic NeoVim configuration
- ✅ Add compiler hints to Bacon export locations - https://github.com/Canop/bacon/pull/187 https://github.com/Canop/bacon/pull/188
- ✅ Support correct span in Bacon export locations - working from
bacon 3.7 and bacon-ls 0.6.0
- ✅ VSCode extension and configuration - available on the release page from 0.6.0
- ✅ VSCode extension published available on Marketplace
- ✅ Add
bacon-ls to bacon website - https://github.com/Canop/bacon/pull/289
- ✅ Smarter handling of parsing the Bacon locations file
- ✅ Faster response after a save event
- ✅ Replacement code actions
- ✅ Validate
bacon preferences and return an error to the LSP client if they are not compatible with bacon - working from bacon-ls 0.9.0
- ✅ Create
bacon preferences file if not found on disk - working from bacon-ls 0.10.0
- ✅ Start
bacon in background based on user preferences - working from bacon-ls 0.10.0
- ✅ Synchronize diagnostics for all open files - working from
bacon-ls 0.10.0
- ✅ Support Helix editor - working from bacon-ls 0.12.0
- 🌍 Emacs configuration
