Kconfig LSP

A minimal language server for the Kconfig language used for build system configuration in many notable projects such as Linux, U-Boot, Zephyr and coreboot.

The language server should generally work in all of these projects and is mainly intended for using in Kconfig files.

Future support for Kconfig symbols in C, .config, defconfigs, and etc. is desired but not yet implemented.

This project mainly provides documentation for most tokens in Kconfig files but hopes to support most LSP methods in the future when I have time to work on it.

The documentation provided by the hover LSP method is provided by Documentation/kbuild/kconfig-language.rst if available otherwise is provided by the kconfig-language.rst that gets installed with this language server. The purpose of this is to try to rely on the most relevant documentation.

An indication (at least in my Neovim config) to where the documentation came from is if the hover is colourful. The kconfig-language.rst document provided by this repo wraps all Kconfig snippets in markdown to identify it. The language server protocol uses markdown for the hover method. My editor picks up these code blocks and colours them. However, if the documentation was found in the repo, it will contain no markdown code blocks (since it is .rst) and my editor does not colour them.

The kconfig-language.rst file is derived from the file of the same name in the Linux kernel source code so this code base is also made available under GPL-2.0 (see LICENSE).

Demo

Dependencies

This application relies on several command line tools, make sure you have installed:

• rg
• jq
• awk
• sed
• bats (optional, for testing)

Installation

Being a single file bash script no building is required and installation is straight-forward. A Makefile is provided for easy installation.

sudo make install
# or
sudo make dev-install # for installing as a symlink
# and
sudo make uninstall # for uninstalling

Testing

This application is tested with bats test framework and ideally features should be added in the future following TDD practices.

make
# or
make test

Note that some tests may be failing for features I have yet to add.

Configuration

Neovim

vim.lsp.config.kconfig = {
    root_markers = { '.git' },
    cmd = { 'kconfig-language-server' },
    filetypes = { 'kconfig' },
}

vim.lsp.enable('kconfig')

Troubleshooting

If the kconfig-language-server fails immediately, this may be due to missing dependencies or other issues. The language server may print an explanation on stdout. Running the language server by itself may print the error. If it just hangs and prints no output then it likely started fine. If it prints an error you can use that to see what caused the error. Its a very small application so reading it will likely be the fastest solution to your issue.

kconfig-language-server

You can use bash -x to print every line as a sort of debug mode:

bash -x kconfig-language-server

Supported LSP Methods

Method	Supported	Comment
textDocument/hover	true
textDocument/definition	false	Higher priority feature
textDocument/completion	false	Higher priority feature
textDocument/references	false	Higher priority feature
textDocument/rename	false	Higher priority feature
textDocument/diagnostic	false	Higher priority feature
callHierarchy/incomingCalls	false	Higher priority feature
callHierarchy/outgoingCalls	false	Higher priority feature
textDocument/codeAction	false	Not a priority
textDocument/declaration	false	Not a priority
textDocument/documentHighlight	false	Not a priority
textDocument/documentSymbol	false	Not a priority
textDocument/foldingRange	false	Not a priority
textDocument/formatting	false	Not a priority
textDocument/implementation	false	Not a priority
textDocument/inlayHint	false	Not a priority
textDocument/prepareTypeHierarchy	false	Not a priority
textDocument/publishDiagnostics	false	Not a priority
textDocument/rangeFormatting	false	Not a priority
textDocument/rangesFormatting	false	Not a priority
textDocument/semanticTokens/full	false	Not a priority
textDocument/semanticTokens/full/delta	false	Not a priority
textDocument/signatureHelp	false	Not a priority
textDocument/typeDefinition	false	Not a priority
typeHierarchy/subtypes	false	Not a priority
typeHierarchy/supertypes	false	Not a priority
window/logMessage	false	Not a priority
window/showMessage	false	Not a priority
window/showDocument	false	Not a priority
window/showMessageRequest	false	Not a priority
workspace/applyEdit	false	Not a priority
workspace/configuration	false	Not a priority
workspace/executeCommand	false	Not a priority
workspace/inlayHint/refresh	false	Not a priority
workspace/symbol	false	Not a priority
workspace/workspaceFolders	false	Not a priority