How to setup setup_handlers correctly?

[florentsorel]

I try to use setup_handlers as a replacement of on_server_ready but I don't know how to have a default behavior for each LSP (like keymap), so how to have a default on_attach, capabilities, etc and merge them without loosing the default behavior.

Currently, [sumneko_lua] and [intelephense] override my default on_attach, so the default on_attach doesn't work.

I've read the docs about this and I even find a question here but I don't know how to merge the default behavior with a custom config for one LSP.

local status, mason = pcall(require, "mason")
if not status then
    return
end

local status2, lspconfig = pcall(require, "mason-lspconfig")
if not status2 then
    return
end

vim.lsp.handlers["textDocument/hover"] = vim.lsp.with(vim.lsp.handlers.hover, {
    border = "rounded",
})

vim.lsp.handlers["textDocument/signatureHelp"] = vim.lsp.with(vim.lsp.handlers.signature_help, {
  border = "rounded",
})

mason.setup({})

lspconfig.setup {
  ensure_installed = { "sumneko_lua", "intelephense" },
  automatic_installation = false,
}


local on_attach = function(client, bufnr)
  -- See `:help vim.lsp.*` for documentation on any of the below functions
  local opts = { noremap = true, silent = true, buffer = bufnr }
  vim.keymap.set('n', 'gd', vim.lsp.buf.definition, opts)
  vim.keymap.set('n', 'gD', vim.lsp.buf.declaration, opts)
  vim.keymap.set('n', 'K', vim.lsp.buf.hover, opts)
  vim.keymap.set('n', 'gi', vim.lsp.buf.implementation, opts)
  vim.keymap.set('n', '<C-k>', vim.lsp.buf.signature_help, opts)
  vim.keymap.set('n', '<Leader>wa', vim.lsp.buf.add_workspace_folder, opts)
  vim.keymap.set('n', '<Leader>wr', vim.lsp.buf.remove_workspace_folder, opts)
  vim.keymap.set('n', '<Leader>wl', function()
    print(vim.inspect(vim.lsp.buf.list_workspace_folders()))
  end, opts)
  vim.keymap.set('n', '<Leader>D', vim.lsp.buf.type_definition, opts)
  vim.keymap.set('n', '<Leader>rn', vim.lsp.buf.rename, opts)
  vim.keymap.set('n', '<Leader>ca', vim.lsp.buf.code_action, opts)
  vim.keymap.set('n', 'gr', vim.lsp.buf.references, opts)
end

lspconfig.setup_handlers {
    function (server_name)
        require("lspconfig")[server_name].setup({
            on_attach = on_attach,
        })
    end,
   -- you can override the default handler by providing custom handlers per server
   ["sumneko_lua"] = function() require("user.lsp.sumneko_lua") end,
   ["intelephense"] = function() require("user.lsp.intelephense") end,
}


-- sumneko_lua.lua
require("lspconfig").sumneko_lua.setup({
  settings = {
    Lua = {
      diagnostics = {
        globals = { "vim" },
      },
      workspace = {
        library = {
          [vim.fn.expand "$VIMRUNTIME/lua"] = true,
          [vim.fn.expand "~/.config/nvim"] = true,
          [vim.fn.expand "~/.local/share/nvim/site/pack/packer/opt/*"] = true,
          [vim.fn.expand "~/.local/share/nvim/site/pack/packer/start/*"] = true,
        },
      },
      telemetry = { enable = false },
    },
  },
})

[jinzhongjia]

you just need to use setup_handlers function ,and you you can give it a table parameter which is like :

 require("mason-lspconfig").setup_handlers {
        -- The first entry (without a key) will be the default handler
        -- and will be called for each installed server that doesn't have
        -- a dedicated handler.
        function (server_name) -- default handler (optional)
            require("lspconfig")[server_name].setup {}
        end,
        -- Next, you can provide a dedicated handler for specific servers.
        -- For example, a handler override for the `rust_analyzer`:
        ["rust_analyzer"] = function ()
            require("rust-tools").setup {}
        end
    }

in the lspconfig's setup, you can put your configuration of lsp into it

setup_handlers is just a hook function, it will recursively mount the parameters passed to it on lspconfig.

Maybe my above example is not clear, you can refer to my neovim-config, I have realized the automatic management of lsp, dap, null-ts through mason

[jinzhongjia]

and you also can use lspconfig.setup to set global config

[williamboman]

In your provided snippet there's no "default" settings, so sumneko_lua and intelephense is not overriding anything - they just have their own code paths.

If you're using Neovim 0.8 or higher I'd recommend making use of the new LspAttach (and LspDetach) autocmds. This way you can decouple configurations, such as having a dedicated callback for setting up LSP keymaps (and keymaps only) when a server attaches:

-- You can place this as a standalone file inside e.g. `plugin/lsp/keymaps.lua`.
-- Because it's inside the `plugin/` directory, Neovim will execute this file automatically for you at startup (:h startup).

---@param bufnr integer
local function setup_buffer_keymaps(bufnr)
  -- See `:help vim.lsp.*` for documentation on any of the below functions
  local opts = { noremap = true, silent = true, buffer = bufnr }
  vim.keymap.set('n', 'gd', vim.lsp.buf.definition, opts)
  vim.keymap.set('n', 'gD', vim.lsp.buf.declaration, opts)
  vim.keymap.set('n', 'K', vim.lsp.buf.hover, opts)
  vim.keymap.set('n', 'gi', vim.lsp.buf.implementation, opts)
  vim.keymap.set('n', '<C-k>', vim.lsp.buf.signature_help, opts)
  vim.keymap.set('n', '<Leader>wa', vim.lsp.buf.add_workspace_folder, opts)
  vim.keymap.set('n', '<Leader>wr', vim.lsp.buf.remove_workspace_folder, opts)
  vim.keymap.set('n', '<Leader>wl', function()
    print(vim.inspect(vim.lsp.buf.list_workspace_folders()))
  end, opts)
  vim.keymap.set('n', '<Leader>D', vim.lsp.buf.type_definition, opts)
  vim.keymap.set('n', '<Leader>rn', vim.lsp.buf.rename, opts)
  vim.keymap.set('n', '<Leader>ca', vim.lsp.buf.code_action, opts)
  vim.keymap.set('n', 'gr', vim.lsp.buf.references, opts)
end

vim.api.nvim_create_autocmd("LspAttach", {
    callback = function(args)
        local bufnr = args.buf
        setup_buffer_keymaps(bufnr)
    end,
})

If you're running an older version I'd recommend looking into :h lspconfig-global-defaults.

[jinzhongjia]

I am now using the on_attach function to mount the key map. What is the difference between this function and "LspAttach"?
such as:

local opt = {
	capabilities = cmp_nvim_lsp.default_capabilities(capabilities),
	flags = {
		debounce_text_changes = 150,
	},
	on_attach = function(client, bufnr)
		-- Disable the formatting function and leave it to a special plug-in plug-in for processing
		client.server_capabilities.documentFormattingProvider = false
		client.server_capabilities.documentRangeFormattingProvider = false

		local function buf_set_keymap(...)
			vim.api.nvim_buf_set_keymap(bufnr, ...)
		end

		-- Bind shortcut keys
		require("keybindings").mapLSP(buf_set_keymap)
		-- Auto format on save
		vim.cmd("autocmd BufWritePre <buffer> lua vim.lsp.buf.format()")
	end,
}