feat: integrate with lspconfig's on_setup hook (#631)

* feat: integrate with lspconfig's on_setup hook

* fix!: don't use aliased installation directories if new .setup() fn is used

This makes it so servers are always installed in a directory name that
corresponds with the server name. The reason aliased installation directories
is supported is lost on me, but it's legacy and complicates things
unnecessarily.

This is a breaking change for users who previously were using the `.on_server_ready()`
hook, and now transitioned to setting up servers directly via lspconfig.
These users will need to reinstall the server.

* fix: block usage of the deprecated server:setup() method if new setup method is used

* fix: allow passing no arg to setup()

* docs: ok final.v3 readme

5 files changed, 59 insertions, 1 deletions

diff --git a/lua/nvim-lsp-installer.lua b/lua/nvim-lsp-installer.lua
index 62b20a1e..a910440e 100644
--- a/lua/nvim-lsp-installer.lua
+++ b/lua/nvim-lsp-installer.lua
@@ -14,6 +14,15 @@ local M = {}
 
 M.settings = settings.set
 
+---@param config table
+function M.setup(config)
+    if config then
+        settings.set(config)
+    end
+    settings.uses_new_setup = true
+    require("nvim-lsp-installer.middleware").register_lspconfig_hook()
+end
+
 M.info_window = {
     ---Opens the status window.
     open = function()
diff --git a/lua/nvim-lsp-installer/middleware.lua b/lua/nvim-lsp-installer/middleware.lua
new file mode 100644
index 00000000..3e01b976
--- /dev/null
+++ b/lua/nvim-lsp-installer/middleware.lua
@@ -0,0 +1,32 @@
+local util = require "lspconfig.util"
+local servers = require "nvim-lsp-installer.servers"
+
+local M = {}
+
+---@param t1 table
+---@param t2 table
+local function merge_in_place(t1, t2)
+    for k, v in pairs(t2) do
+        if type(v) == "table" then
+            if type(t1[k]) == "table" and not vim.tbl_islist(t1[k]) then
+                merge_in_place(t1[k], v)
+            else
+                t1[k] = v
+            end
+        else
+            t1[k] = v
+        end
+    end
+    return t1
+end
+
+function M.register_lspconfig_hook()
+    util.on_setup = util.add_hook_before(util.on_setup, function(config)
+        local ok, server = servers.get_server(config.name)
+        if ok then
+            merge_in_place(config, server._default_options)
+        end
+    end)
+end
+
+return M
diff --git a/lua/nvim-lsp-installer/server.lua b/lua/nvim-lsp-installer/server.lua
index de6481a4..66d9655f 100644
--- a/lua/nvim-lsp-installer/server.lua
+++ b/lua/nvim-lsp-installer/server.lua
@@ -71,6 +71,10 @@ end
 ---Sets up the language server and attaches all open buffers.
 ---@param opts table @The lspconfig server configuration.
 function M.Server:setup(opts)
+    assert(
+        not settings.uses_new_setup,
+        "Please set up servers directly via lspconfig instead of going through nvim-lsp-installer (this method is now deprecated)! Refer to :h nvim-lsp-installer-quickstart for more information."
+    )
     self:setup_lsp(opts)
     if not (opts.autostart == false) then
         self:attach_buffers()
diff --git a/lua/nvim-lsp-installer/servers/init.lua b/lua/nvim-lsp-installer/servers/init.lua
index efca1dd5..9af4c1bb 100644
--- a/lua/nvim-lsp-installer/servers/init.lua
+++ b/lua/nvim-lsp-installer/servers/init.lua
@@ -2,6 +2,7 @@ local Data = require "nvim-lsp-installer.data"
 local path = require "nvim-lsp-installer.path"
 local fs = require "nvim-lsp-installer.fs"
 local settings = require "nvim-lsp-installer.settings"
+local log = require "nvim-lsp-installer.log"
 
 local M = {}
 
@@ -180,15 +181,22 @@ end
 ---@param server_name string
 ---@return string
 local function get_server_install_dir(server_name)
-    return INSTALL_DIRS[server_name] or server_name
+    log.fmt_trace("Getting server installation dirname. uses_new_setup=%s", settings.uses_new_setup)
+    if settings.uses_new_setup then
+        return server_name
+    else
+        return INSTALL_DIRS[server_name] or server_name
+    end
 end
 
 function M.get_server_install_path(dirname)
+    log.trace("Getting server installation path", settings.current.install_root_dir, dirname)
     return path.concat { settings.current.install_root_dir, dirname }
 end
 
 ---@param server_name string
 function M.is_server_installed(server_name)
+    log.trace("Checking if server is installed", server_name)
     local scanned_server_dirs = scan_server_roots()
     local dirname = get_server_install_dir(server_name)
     return scanned_server_dirs[dirname] or false
@@ -213,6 +221,7 @@ function M.get_server(server_name)
 
     local ok, server_factory = pcall(require, ("nvim-lsp-installer.servers.%s"):format(server_name))
     if ok then
+        log.trace("Initializing core server", server_name)
         INITIALIZED_SERVERS[server_name] = server_factory(
             server_name,
             M.get_server_install_path(get_server_install_dir(server_name))
diff --git a/lua/nvim-lsp-installer/settings.lua b/lua/nvim-lsp-installer/settings.lua
index ad875b72..87499354 100644
--- a/lua/nvim-lsp-installer/settings.lua
+++ b/lua/nvim-lsp-installer/settings.lua
@@ -59,4 +59,8 @@ function M.set(opts)
     M.current = vim.tbl_deep_extend("force", M.current, opts)
 end
 
+-- Whether the new .setup() function has been called.
+-- This will temporarily be used as a flag to toggle certain behavior.
+M.uses_new_setup = false
+
 return M