nvim: Drop nvim-lspconfig

Use the new vim.lsp.start API and LspAttach/Detach auto commands.
Drop nvim-lspconfig in the process.

LSP server specific configuration has been taken from nvim-lspconfig.

nvim/.config/nvim/after/ftplugin/c.lua

@@ -0,0 +1,22 @@
+local default_capabilities = {
+  textDocument = {
+    completion = {
+      editsNearCursor = true,
+    },
+  },
+  offsetEncoding = { 'utf-8', 'utf-16' },
+}
+
+local root_files = { '.clangd', '.clang-tidy', '.clang-format', 'compile_commands.json', 'compile_flags.txt' }
+local clangd_cmd = { "clangd", "--background-index", "--pch-storage=memory", "--clang-tidy", "--header-insertion=never" }
+local path       = vim.fs.find(root_files, { type = "file" })
+local root       = vim.fs.dirname(path[1])
+
+vim.lsp.start({
+  name                = "clangd",
+  cmd                 = clangd_cmd,
+  root_dir            = root,
+  filetypes           = { 'c', 'cpp' },
+  single_file_support = true,
+  capabilities        = default_capabilities,
+})

nvim/.config/nvim/after/ftplugin/haskell.lua

@@ -0,0 +1,12 @@
+local root_files = { 'hie.yaml', 'stack.yaml', 'cabal.project', '*.cabal', 'package.yaml' }
+local path       = vim.fs.find(root_files, { type = "file" })
+local root       = vim.fs.dirname(path[1])
+
+vim.lsp.start({
+  name                = "hls",
+  cmd                 = { 'haskell-language-server-wrapper', '--lsp' },
+  root_dir            = root,
+  filetypes           = { 'haskell' },
+  single_file_support = true,
+  settings            = { haskell = { formattingProvider = 'ormolu' } },
+})

nvim/.config/nvim/after/ftplugin/javascript.lua

@@ -0,0 +1,34 @@
+local root_files = { 'jsconfig.json', 'tsconfig.json', 'package.json' }
+local file_types = { 'javascript', 'javascriptreact', 'javascript.jsx', 'typescript', 'typescriptreact', 'typescript.tsx' }
+local path       = vim.fs.find(root_files, { type = "file" })
+
+vim.lsp.start({
+  name      = "tsserver",
+  cmd       = { "typescript-language-server", "--stdio" },
+  root_dir  = vim.fs.dirname(path[1]),
+  filetypes = file_types,
+  settings = {
+    typescript = {
+      inlayHints = {
+        includeInlayParameterNameHints                        = 'all',
+        includeInlayParameterNameHintsWhenArgumentMatchesName = false,
+        includeInlayFunctionParameterTypeHints                = true,
+        includeInlayVariableTypeHints                         = true,
+        includeInlayPropertyDeclarationTypeHints              = true,
+        includeInlayFunctionLikeReturnTypeHints               = true,
+        includeInlayEnumMemberValueHints                      = true,
+      }
+    },
+    javascript = {
+      inlayHints = {
+        includeInlayParameterNameHints                        = 'all',
+        includeInlayParameterNameHintsWhenArgumentMatchesName = false,
+        includeInlayFunctionParameterTypeHints                = true,
+        includeInlayVariableTypeHints                         = true,
+        includeInlayPropertyDeclarationTypeHints              = true,
+        includeInlayFunctionLikeReturnTypeHints               = true,
+        includeInlayEnumMemberValueHints                      = true,
+      }
+    }
+  }
+})

nvim/.config/nvim/after/ftplugin/python.lua

@@ -0,0 +1,23 @@
+local root_files = { 'pyproject.toml', 'setup.py', 'setup.cfg', 'requirements.txt', 'Pipfile' }
+local path       = vim.fs.find(root_files, { type = "file" })
+local root       = vim.fs.dirname(path[1])
+
+vim.lsp.start({
+  name      = "jedi-language-server",
+  cmd       = { "jedi-language-server" },
+  filetypes = { 'python' },
+  root_dir  = root,
+  init_options = {
+    completion = {
+      resolveEagerly = true,
+    },
+    jediSettings = {
+      caseInsensitiveCompletion = false,
+    },
+    workspace = {
+      symbols = {
+        maxSymbols = 50
+      },
+    },
+  },
+})

nvim/.config/nvim/after/ftplugin/rust.lua

@@ -0,0 +1,18 @@
+local path = vim.fs.find({ "Cargo.toml" }, { type = "file" })
+local root = vim.fs.dirname(path[1])
+
+vim.lsp.start({
+  name     = "rust-analyzer",
+  cmd      = { "rust-analyzer" },
+  root_dir = root,
+  settings = {
+    ["rust-analyzer"] = {
+      procMacro = {
+        enable = true
+      },
+      checkOnSave = {
+        command = "clippy"
+      },
+    },
+  },
+})

nvim/.config/nvim/after/ftplugin/typescript.lua

@@ -0,0 +1,34 @@
+local root_files = { 'jsconfig.json', 'tsconfig.json', 'package.json' }
+local file_types = { 'javascript', 'javascriptreact', 'javascript.jsx', 'typescript', 'typescriptreact', 'typescript.tsx' }
+local path       = vim.fs.find(root_files, { type = "file" })
+
+vim.lsp.start({
+  name      = "tsserver",
+  cmd       = { "typescript-language-server", "--stdio" },
+  root_dir  = vim.fs.dirname(path[1]),
+  filetypes = file_types,
+  settings = {
+    typescript = {
+      inlayHints = {
+        includeInlayParameterNameHints                        = 'all',
+        includeInlayParameterNameHintsWhenArgumentMatchesName = false,
+        includeInlayFunctionParameterTypeHints                = true,
+        includeInlayVariableTypeHints                         = true,
+        includeInlayPropertyDeclarationTypeHints              = true,
+        includeInlayFunctionLikeReturnTypeHints               = true,
+        includeInlayEnumMemberValueHints                      = true,
+      }
+    },
+    javascript = {
+      inlayHints = {
+        includeInlayParameterNameHints                        = 'all',
+        includeInlayParameterNameHintsWhenArgumentMatchesName = false,
+        includeInlayFunctionParameterTypeHints                = true,
+        includeInlayVariableTypeHints                         = true,
+        includeInlayPropertyDeclarationTypeHints              = true,
+        includeInlayFunctionLikeReturnTypeHints               = true,
+        includeInlayEnumMemberValueHints                      = true,
+      }
+    }
+  }
+})

nvim/.config/nvim/lua/lsp.lua

@@ -1,6 +1,4 @@
-local nvim_lsp   = require 'lspconfig'
 local protocol   = require 'vim.lsp.protocol'
-local util       = require 'lspconfig/util'
 local lightbulb  = require 'nvim-lightbulb'
 local inlay_hint = require 'lsp-inlayhints'
 
@@ -65,6 +63,8 @@ protocol.CompletionItemKind = {
   ' TypeParameter';
 }
 
+local lsp_augroup_id = vim.api.nvim_create_augroup("LSP", { clear = true })
+
 local lsp_key_mappings = {
   { "definitionProvider"     , 'n', 'pd'       , '<cmd>lua PeekDefinition()<CR>'               },
   { "definitionProvider"     , 'n', 'gd'       , '<cmd>lua vim.lsp.buf.definition()<CR>'       },
@@ -95,6 +95,49 @@ local tsserver_setup = function(client)
   end
 end
 
+local get_active_client_by_name = function(bufnr, servername)
+  for _, client in pairs(vim.lsp.buf_get_clients(bufnr)) do
+    if client.name == servername then
+      return client
+    end
+  end
+end
+
+local switch_source_header = function()
+  local clangd_client = get_active_client_by_name(0, 'clangd')
+  local params = { uri = vim.uri_from_bufnr(0) }
+
+  if clangd_client then
+    clangd_client.request('textDocument/switchSourceHeader', params, function(err, result)
+      if err then
+        print 'Error dane'
+        error(tostring(err))
+      end
+
+      if not result then
+        print 'Corresponding file cannot be determined'
+        return
+      end
+
+      vim.api.nvim_command('edit ' .. vim.uri_to_fname(result))
+    end, 0)
+  else
+    print 'Method switchSourceHeader is not supported by server active on the current buffer'
+  end
+end
+
+local clangd_setup = function(client)
+  if client.name == 'clangd' then
+    vim.api.nvim_create_user_command("ClangdSwitchSourceHeader", switch_source_header, {desc = 'Switch between source/header'})
+  end
+end
+
+local clangd_cleanup = function(client)
+  if client.name == 'clangd' then
+    vim.api.nvim_del_user_command("ClangdSwitchSourceHeader")
+  end
+end
+
 local on_attach = function(client, bufnr)
   vim.api.nvim_buf_set_option(bufnr, 'omnifunc', 'v:lua.vim.lsp.omnifunc')
   vim.lsp.set_log_level('warn')
@@ -110,6 +153,8 @@ local on_attach = function(client, bufnr)
   -- actually checking it below.
   tsserver_setup(client)
 
+  clangd_setup(client)
+
   for _, mappings in pairs(lsp_key_mappings) do
     local capability, mode, lhs, rhs = unpack(mappings)
     if client.server_capabilities[capability] then
@@ -118,8 +163,6 @@ local on_attach = function(client, bufnr)
   end
 
   if client.server_capabilities.codeLensProvider or client.server_capabilities.documentHighlightProvider then
-    local lsp_augroup_id = vim.api.nvim_create_augroup("LSP", {clear = true})
-
     if client.server_capabilities.codeLensProvider then
       vim.api.nvim_buf_set_keymap(bufnr, "n", "<Leader>l", "<cmd>lua vim.lsp.codelens.run()<CR>", opts)
       vim.api.nvim_create_autocmd({"CursorHold", "CursorHoldI", "InsertLeave"}, {
@@ -159,97 +202,37 @@ local on_attach = function(client, bufnr)
   inlay_hint.on_attach(client, bufnr)
 end
 
-local on_init = function(client)
-  if client.config.settings then
-    client.notify('workspace/didChangeConfiguration', { settings = client.config.settings })
-  end
-end
+vim.api.nvim_create_autocmd("LspAttach", {
+  group = lsp_augroup_id,
+  callback = function(args)
+    local bufnr = args.buf
+    local client = vim.lsp.get_client_by_id(args.data.client_id)
+    local opts = { noremap=true, silent=true }
 
-local capabilities = vim.lsp.protocol.make_client_capabilities()
-capabilities.workspace.configuration = true
-capabilities.textDocument.completion.completionItem.snippetSupport = true
-capabilities.textDocument.completion.completionItem.resolveSupport = {
-  properties = { 'documentation', 'detail', 'additionalTextEdits', }
-}
+    for _, mappings in pairs(lsp_key_mappings) do
+      local capability, mode, lhs, rhs = unpack(mappings)
+      if client.server_capabilities[capability] then
+        vim.api.nvim_buf_set_keymap(bufnr, mode, lhs, rhs, opts)
+      end
+    end
 
-local servers = {
-  clangd = {
-    default_config = {
-      cmd       = { "clangd", "--background-index", "--pch-storage=memory", "--clang-tidy", "--header-insertion=never" },
-      filetypes = { 'c', 'cpp' },
-      root_dir = function(fname)
-        -- We specify build/compile_commands.json as that is where the compile_commands.json
-        -- gets generated automatically for meson projects.
-        local root_pattern = util.root_pattern('build/compile_commands.json', 'compile_commands.json', 'compile_flags.txt', '.git')
-        local filename     = util.path.is_absolute(fname) and fname or util.path.join(vim.loop.cwd(), fname)
-        return root_pattern(filename) or util.path.dirname(filename)
-      end,
-    }
-  },
-  eslint = {},
-  hls = {},
-  jedi_language_server = {
-    init_options = {
-      completion = {
-        resolveEagerly = true,
-      },
-      jediSettings = {
-        caseInsensitiveCompletion = false,
-      },
-      workspace = {
-        symbols = {
-          maxSymbols = 50
-        },
-      },
-    },
-  },
-  rust_analyzer = {
-    settings = {
-      ["rust-analyzer"] = {
-        procMacro = {
-          enable = true
-        },
-        checkOnSave = {
-          command = "clippy"
-        },
-      }
-    }
-  },
-  tsserver = {
-    settings = {
-      typescript = {
-        inlayHints = {
-          includeInlayParameterNameHints = 'all',
-          includeInlayParameterNameHintsWhenArgumentMatchesName = false,
-          includeInlayFunctionParameterTypeHints = true,
-          includeInlayVariableTypeHints = true,
-          includeInlayPropertyDeclarationTypeHints = true,
-          includeInlayFunctionLikeReturnTypeHints = true,
-          includeInlayEnumMemberValueHints = true,
-        }
-      },
-      javascript = {
-        inlayHints = {
-          includeInlayParameterNameHints = 'all',
-          includeInlayParameterNameHintsWhenArgumentMatchesName = false,
-          includeInlayFunctionParameterTypeHints = true,
-          includeInlayVariableTypeHints = true,
-          includeInlayPropertyDeclarationTypeHints = true,
-          includeInlayFunctionLikeReturnTypeHints = true,
-          includeInlayEnumMemberValueHints = true,
-        }
-      }
-    }
-  },
-}
+    on_attach(client, bufnr)
+  end,
+})
 
-for client, config in pairs(servers) do
-  config.on_init      = on_init
-  config.on_attach    = on_attach
-  config.capabilities = vim.tbl_deep_extend(
-    'keep',
-    config.capabilities or {},
-    capabilities
-  )
-  nvim_lsp[client].setup(config)
-end
+vim.api.nvim_create_autocmd("LspDetach", {
+  group = lsp_augroup_id,
+  callback = function(args)
+    local bufnr = args.buf
+    local client = vim.lsp.get_client_by_id(args.data.client_id)
+
+    for _, mappings in pairs(lsp_key_mappings) do
+      local capability, mode, lhs, _ = unpack(mappings)
+      if client.server_capabilities[capability] then
+        vim.api.nvim_buf_del_keymap(bufnr, mode, lhs)
+      end
+    end
+
+    clangd_cleanup(client)
+  end,
+})

nvim/.config/nvim/lua/plugins.lua

@@ -63,10 +63,7 @@ local init = function ()
   use 'junegunn/vim-easy-align'
   use 'nvim-lua/plenary.nvim'
   -- LSP
-  use {
-    'neovim/nvim-lspconfig',
-    'kosayoda/nvim-lightbulb',
-  }
+  use 'kosayoda/nvim-lightbulb'
   -- Language support & syntax highlighting
   use 'mfussenegger/nvim-lint'
   use 'lvimuser/lsp-inlayhints.nvim'