lsp-filter

lsp-filter can wrap a language server binary and customize the initialize message response by disabling certain semantic providers.

For example, you can use cquery and clangd together by disabling completion for cquery and disabling everything except completion for clangd.

Installation

$ go get -u github.com/jacobdufault/lsp-filter
$ lsp-filter # prints out help/usage

Example

Install the vscode clangd and cquery extensions, and use clangd-filter.sh and cquery-filter.sh as the language server binary instead of cquery or clangd.

$ cat clangd-filter.sh
#!/usr/bin/env /bin/sh
exec lsp-filter clangd enable completion signatureHelp codeAction executeCommand -- "$@"

$ cat cquery-filter.sh
#!/usr/bin/env /bin/sh
exec lsp-filter cquery disable completion signatureHelp codeAction -- "$@"

vscode settings file:

{
  // ...
  "clangd.path": "clangd-filter.sh",
  "cquery.launch.command": "cquery-filter.sh",
  // ...

  // You'll probably also want to turn off diagnostics for cquery, since clangd
  // provides those.
  "cquery.diagnostics.onParse": false,
  "cquery.diagnostics.onType": false,
}

Make sure clangd-filter.sh and cquery-filter.sh are in your PATH.

Custom compile_commands.json directory

By default clangd only searches for compile_commands.json in the parent directories of the source files that are being analyzed. However, some build systems such as CMake store their generated compile_commands.json in the build directory itself which is often not a parent directory of the source files (e.g. when using src/ and build/ directories). To make clangd look for the compile_commands.json file in a custom directory we have to specify an extra option when launching clangd:

$ cat clangd-filter.sh
#!/usr/bin/env /bin/sh
exec lsp-filter clangd enable completion signatureHelp codeAction executeCommand -- -compile-commands-dir=$PWD/build "$@"

This assumes that clangd is started in the root directory of the current project so that $PWD refers to the root directory of the project.