LSP configuration

Default keymaps

Here's the description of the keymaps recommended in the getting started page:

• K: Displays hover information about the symbol under the cursor in a floating window. See :help vim.lsp.buf.hover().

• gd: Jumps to the definition of the symbol under the cursor. See :help vim.lsp.buf.definition().

• gD: Jumps to the declaration of the symbol under the cursor. Some servers don't implement this feature. See :help vim.lsp.buf.declaration().

• gi: Lists all the implementations for the symbol under the cursor in the quickfix window. See :help vim.lsp.buf.implementation().

• go: Jumps to the definition of the type of the symbol under the cursor. See :help vim.lsp.buf.type_definition().

• gr: Lists all the references to the symbol under the cursor in the quickfix window. See :help vim.lsp.buf.references().

• gs: Displays signature information about the symbol under the cursor in a floating window. See :help vim.lsp.buf.signature_help(). If a mapping already exists for this key this function is not bound.

• <F2>: Renames all references to the symbol under the cursor. See :help vim.lsp.buf.rename().

• <F3>: Format code in current buffer. See :help vim.lsp.buf.format().

• <F4>: Selects a code action available at the current cursor position. See :help vim.lsp.buf.code_action().

These keymaps can also be created using the function lsp-zero.default_keymaps().

local lsp_zero = require('lsp-zero')

local lsp_attach = function(client, bufnr)
  lsp_zero.default_keymaps({buffer = bufnr})
end

lsp_zero.extend_lspconfig({
  lsp_attach = lsp_attach,
})

By default lsp-zero will not create a keymap if it's "taken". This means if you already use one of these in your config, or some other plugins uses it (which-key might be one), then lsp-zero's bindings will not work.

You can force lsp-zero's bindings by adding preserve_mappings = false to lsp-zero.default_keymaps().

local lsp_attach = function(client, bufnr)
  lsp_zero.default_keymaps({
    buffer = bufnr,
    preserve_mappings = false
  })
end

If you want lsp-zero to skip only a few keys you can add the exclude property to the lsp-zero.default_keymaps() call. Say you want to keep the default behavior of K and gr, you would do this.

local lsp_attach = function(client, bufnr)
  lsp_zero.default_keymaps({
    buffer = bufnr,
    exclude = {'gr', 'K'},
  })
end

Install new language servers

Manual install

You can find install instructions for each language server in lspconfig's documentation: server_configurations.md.

Via command

If you have mason.nvim and mason-lspconfig installed you can use the command :LspInstall to install a language server. If you call this command while you are in a file it'll suggest a list of language server based on the type of that file.

Automatic installs

If you have mason.nvim and mason-lspconfig, you can instruct mason-lspconfig to install the language servers you want using the option ensure_installed.

Note:

The name of the language server you want to install must be on this list.

local lsp_zero = require('lsp-zero')

local lsp_attach = function(client, bufnr)
  -- this is where you enable features that only work
  -- if there is a language server active in the file
end

lsp_zero.extend_lspconfig({
  sign_text = true,
  lsp_attach = lsp_attach,
})

require('mason').setup({})
require('mason-lspconfig').setup({
  -- Replace the language servers listed here
  -- with the ones you want to install
  ensure_installed = {'lua_ls', 'rust_analyzer'},
  handlers = {
    function(server_name)
      require('lspconfig')[server_name].setup({})
    end,
  }
})

We add a "default handler" to the handlers option so we can get automatic setup for all the language servers installed with mason.nvim.

Configure language servers

To pass arguments to a language server you can use the lspconfig directly.

local lsp_zero = require('lsp-zero')

local lsp_attach = function(client, bufnr)
  -- this is where you enable features that only work
  -- if there is a language server active in the file
end

lsp_zero.extend_lspconfig({
  sign_text = true,
  lsp_attach = lsp_attach,
})

require('lspconfig').biome.setup({
  single_file_support = false,
  on_attach = function(client, bufnr)
    print('hello biome')
  end
})

If you use mason-lspconfig handlers to manage the setup of your language servers then you will need to add a custom handler. Here is an example.

require('mason-lspconfig').setup({
  handlers = {
    -- this first function is the "default handler"
    -- it applies to every language server without a "custom handler"
    function(server_name)
      require('lspconfig')[server_name].setup({})
    end,

    -- this is the "custom handler" for `biome`
    biome = function()
      require('lspconfig').biome.setup({
        single_file_support = false,
        on_attach = function(client, bufnr)
          print('hello biome')
        end
      })
    end,
  }
})

Notice in handlers there is a new property with the name of the language server and it has a function assign to it. That is where you configure the language server.

Disable semantic highlights

Neovim v0.9 allows a language server to apply new highlights, this is known as semantic tokens. This new feature is enabled by default. To disable it we need to modify the server_capabilities property of the language server, more specifically we need to "delete" the semanticTokensProvider property.

We can disable this new feature in every server whenever they attach to a buffer.

local lsp_zero = require('lsp-zero')

local lsp_attach = function(client, bufnr)
  -- Disable semantic highlights
  client.server_capabilities.semanticTokensProvider = nil
end

lsp_zero.extend_lspconfig({
  sign_text = true,
  lsp_attach = lsp_attach,
})

If you just want to disable it for a particular server, use lspconfig to assign the on_attach hook to that server.

require('lspconfig').lua_ls.setup({
  on_attach = function(client)
    client.server_capabilities.semanticTokensProvider = nil
  end,
})

Disable formatting capabilities

Sometimes you might want to prevent Neovim from using a language server as a formatter. For this you can use the on_attach hook to modify the client instance.

require('lspconfig').lua_ls.setup({
  on_attach = function(client)
    client.server_capabilities.documentFormattingProvider = false
    client.server_capabilities.documentFormattingRangeProvider = false
  end,
})

Custom servers

There are two ways you can use a server that is not supported by lspconfig:

Add the configuration to lspconfig (recommended)

You can add the configuration to the module lspconfig.configs then you can call the .setup() function.

You'll need to provide the command that starts the language server, a list of filetypes where you want to attach the language server, and a function that detects the "root directory" of the project.

Note: before doing anything, make sure the server you want to add is not supported by lspconfig. Read the list of supported language servers.

local lsp_zero = require('lsp-zero')

local lsp_attach = function(client, bufnr)
  -- this is where you enable features that only work
  -- if there is a language server active in the file
end

lsp_zero.extend_lspconfig({
  sign_text = true,
  lsp_attach = lsp_attach,
})

local lsp_configurations = require('lspconfig.configs')

if not lsp_configurations.name_of_my_lsp then
  lsp_configurations.name_of_my_lsp = {
    default_config = {
      cmd = {'command-that-start-the-lsp'},
      filetypes = {'my-filetype'},
      root_dir = require('lspconfig.util').root_pattern('some-config-file')
    }
  }
end

require('lspconfig').name_of_my_lsp.setup({})

Note:

root_pattern expects a list of files. The files that you list there should help lspconfig identify the root of your project.

Use the function .new_client()

If you don't need a "robust" solution you can use the function lsp-zero.new_client(). This function is just a thin wrapper that calls vim.lsp.start() in a FileType autocommand.

local lsp_zero = require('lsp-zero')

lsp_zero.new_client({
  name = 'my-new-lsp',
  cmd = {'command-that-start-the-lsp'},
  filetypes = {'my-filetype'},
  root_dir = function()
    return lsp_zero.dir.find_first({'some-config-file'}) 
  end
})

Enable Format on save

You have two ways to enable format on save.

Note: When you enable format on save your language server is doing the formatting. The language server does not share the same style configuration as Neovim. Tabs and indents can change after the language server formats the code in the file. Read the documentation of the language server you are using, figure out how to configure it to your prefered style.

Explicit setup

If you want to control exactly what language server is used to format a file call the function lsp-zero.format_on_save(), this will allow you to associate a language server with a list of filetypes.

local lsp_zero = require('lsp-zero')

-- don't add this function in the `lsp_attach` callback.
-- `format_on_save` should run only once, before the language servers are active.
lsp_zero.format_on_save({
  format_opts = {
    async = false,
    timeout_ms = 10000,
  },
  servers = {
    ['biome'] = {'javascript', 'typescript'},
    ['rust_analyzer'] = {'rust'},
  }
})

Always use the active servers

If you only ever have one language server attached in each file and you are happy with all of them, you can call the function lsp-zero.buffer_autoformat() when a language server is active in the current buffer.

local lsp_zero = require('lsp-zero')

local lsp_attach = function(client, bufnr)
  lsp_zero.buffer_autoformat()
end

lsp_zero.extend_lspconfig({
  sign_text = true,
  lsp_attach = lsp_attach,
})

If you have multiple servers active in one file it'll try to format using all of them, and I can't guarantee the order.

It's worth mentioning lsp-zero.buffer_autoformat() is a blocking (synchronous) function. If you want something that behaves like lsp-zero.buffer_autoformat() but is asynchronous you'll have to use lsp-format.nvim.

local lsp_zero = require('lsp-zero')

local lsp_attach = function(client, bufnr)
  -- make sure you use clients with formatting capabilities
  -- otherwise you'll get a warning message
  if client.supports_method('textDocument/formatting') then
    require('lsp-format').on_attach(client)
  end
end

lsp_zero.extend_lspconfig({
  sign_text = true,
  lsp_attach = lsp_attach,
})

Format using a keybinding

Using built-in functions

You'll want to bind the function vim.lsp.buf.format() to a keymap. The next example will create a keymap gq to format the current buffer using all active servers with formatting capabilities.

local lsp_zero = require('lsp-zero')

local lsp_attach = function(client, bufnr)
  local opts = {buffer = bufnr}

  vim.keymap.set({'n', 'x'}, 'gq', function()
    vim.lsp.buf.format({async = false, timeout_ms = 10000})
  end, opts)
end

lsp_zero.extend_lspconfig({
  sign_text = true,
  lsp_attach = lsp_attach,
})

If you want to allow only a list of servers, use the filter option. You can create a function that compares the current server with a list of allowed servers.

local lsp_zero = require('lsp-zero')

local allow_format = function(servers)
  return function(client) return vim.tbl_contains(servers, client.name) end
end

local lsp_attach = function(client, bufnr)
  local opts = {buffer = bufnr}

  vim.keymap.set({'n', 'x'}, 'gq', function()
    vim.lsp.buf.format({
      async = false,
      timeout_ms = 10000,
      filter = allow_format({'lua_ls', 'rust_analyzer'})
    })
  end, opts)
end

lsp_zero.extend_lspconfig({
  sign_text = true,
  lsp_attach = lsp_attach,
})

Ensure only one language server per filetype

If you want to control exactly what language server can format, use the function lsp-zero.format_mapping(). It will allow you to associate a list of filetypes to a particular language server.

Here is an example using gq as the keymap.

local lsp_zero = require('lsp-zero')

local lsp_attach = function(client, bufnr)
  -- this is where you enable features that only work
  -- if there is a language server active in the file
end

lsp_zero.extend_lspconfig({
  sign_text = true,
  lsp_attach = lsp_attach,
})

-- don't add this function in the `lsp_attach` callback.
-- `format_mapping` should run only once, before the language servers are active.
lsp_zero.format_mapping('gq', {
  format_opts = {
    async = false,
    timeout_ms = 10000,
  },
  servers = {
    ['biome'] = {'javascript', 'typescript'},
    ['rust_analyzer'] = {'rust'},
  }
})

How to format file using [tool]?

Where [tool] can be prettier or black or stylua or any command line tool that was create before the LSP protocol existed.

Short answer: You need some sort of adapter. Another plugin or a language server that can communicate with [tool].

Long answer: Your question should be more specific to Neovim and not lsp-zero. You should be looking for "how to make vim.lsp.buf.format() use [tool]?" And once you know how to do that you can use one of lsp-zero helper functions... or just vim.lsp.buf.format().

If you really want to integrate that command line tool with Neovim's LSP client, these are your options:

• efm-langserver
• none-ls

Personally, I would use a plugin that communicates directly with the CLI tool. Here are a few options:

• conform.nvim
• Formatter.nvim
• guard.nvim

If you are going that route and you are wondering which one to choose, use conform.nvim. People say it's good. Don't think about it too much.

Diagnostics

The function lsp-zero.extend_lspconfig() has the option sign_text, with it you can enable or disable the diagnostic signs.

The value true will enable diagnostic signs in the vim.diagnostic module. It will also change the value of the vim option signcolumn from "auto" to "yes" to avoid a layout shift when signs appear on screen.

lsp_zero.extend_lspconfig({
  sign_text = true,
})

If sign_text is false it will disable diagnostic signs in the vim.diagnostic module. The vim option signcolumn will not be modified.

lsp_zero.extend_lspconfig({
  sign_text = false,
})

sign_text can also be a table, this will allow you to change the text of diagnostic signs.

lsp_zero.extend_lspconfig({
  sign_text = {
    error = '✘',
    warn = '▲',
    hint = '⚑',
    info = '»',
  },
})

If you don't provide sign_text to extend_lspconfig() you get the default behavior your Neovim version has for diagnostic signs.

How does it work?

Language servers are configured and initialized using nvim-lspconfig.

lsp-zero first adds data to an option called capabilities in lspconfig's defaults. This new data comes from cmp-nvim-lsp. It tells the language server what features nvim-cmp adds to the editor.

Then it creates an autocommand on the event LspAttach. This autocommand will be triggered every time a language server is attached to a buffer. This is where all keybindings and commands are created.

So this example configuration

local lsp_zero = require('lsp-zero')

local lsp_attach = function(client, bufnr)
  lsp_zero.default_keymaps({buffer = bufnr})
end

lsp_zero.extend_lspconfig({
  sign_text = true,
  lsp_attach = lsp_attach,
  capabilities = require('cmp_nvim_lsp').default_capabilities()
})

require('lspconfig').gleam.setup({})
require('lspconfig').rust_analyzer.setup({})

Is the same as this:

vim.opt.signcolumn = 'yes'

vim.diagnostic.config({
  signs = true
})

local lspconfig = require('lspconfig')

lspconfig.util.default_config.capabilities = vim.tbl_deep_extend(
  'force',
  lspconfig.util.default_config.capabilities,
  require('cmp_nvim_lsp').default_capabilities()
)

vim.api.nvim_create_autocmd('LspAttach', {
  desc = 'LSP actions',
  callback = function(event)
    local opts = {buffer = event.buf}

    vim.keymap.set('n', 'K', '<cmd>lua vim.lsp.buf.hover()<cr>', opts)
    vim.keymap.set('n', 'gd', '<cmd>lua vim.lsp.buf.definition()<cr>', opts)
    vim.keymap.set('n', 'gD', '<cmd>lua vim.lsp.buf.declaration()<cr>', opts)
    vim.keymap.set('n', 'gi', '<cmd>lua vim.lsp.buf.implementation()<cr>', opts)
    vim.keymap.set('n', 'go', '<cmd>lua vim.lsp.buf.type_definition()<cr>', opts)
    vim.keymap.set('n', 'gr', '<cmd>lua vim.lsp.buf.references()<cr>', opts)
    vim.keymap.set('n', 'gs', '<cmd>lua vim.lsp.buf.signature_help()<cr>', opts)
    vim.keymap.set('n', '<F2>', '<cmd>lua vim.lsp.buf.rename()<cr>', opts)
    vim.keymap.set({'n', 'x'}, '<F3>', '<cmd>lua vim.lsp.buf.format({async = true})<cr>', opts)
    vim.keymap.set('n', '<F4>', '<cmd>lua vim.lsp.buf.code_action()<cr>', opts)
  end,
})

lspconfig.gleam.setup({})
lspconfig.rust_analyzer.setup({})