feat: pass user config to the on_setup hook (#2114)

This is to allow 3rd party plugins to discern between what is
lspconfig's vendored server config and what the user provided.
Currently, these are merged into a single table which is passed to the
on_setup hook. Passing user_config as a 2nd argument would allow 3rd
party plugins to apply a more sensible precedence of configs.

2 files changed, 29 insertions, 11 deletions

diff --git a/lua/lspconfig/configs.lua b/lua/lspconfig/configs.lua
index a0129776..b963e424 100644
--- a/lua/lspconfig/configs.lua
+++ b/lua/lspconfig/configs.lua
@@ -30,19 +30,19 @@ function configs.__newindex(t, config_name, config_def)
   -- Force this part.
   default_config.name = config_name
 
-  function M.setup(config)
+  function M.setup(user_config)
     local lsp_group = vim.api.nvim_create_augroup('lspconfig', { clear = false })
 
     validate {
-      cmd = { config.cmd, 't', true },
-      root_dir = { config.root_dir, 'f', true },
-      filetypes = { config.filetype, 't', true },
-      on_new_config = { config.on_new_config, 'f', true },
-      on_attach = { config.on_attach, 'f', true },
-      commands = { config.commands, 't', true },
+      cmd = { user_config.cmd, 't', true },
+      root_dir = { user_config.root_dir, 'f', true },
+      filetypes = { user_config.filetype, 't', true },
+      on_new_config = { user_config.on_new_config, 'f', true },
+      on_attach = { user_config.on_attach, 'f', true },
+      commands = { user_config.commands, 't', true },
     }
-    if config.commands then
-      for k, v in pairs(config.commands) do
+    if user_config.commands then
+      for k, v in pairs(user_config.commands) do
         validate {
           ['command.name'] = { k, 's' },
           ['command.fn'] = { v[1], 'f' },
@@ -50,10 +50,10 @@ function configs.__newindex(t, config_name, config_def)
       end
     end
 
-    config = tbl_deep_extend('keep', config, default_config)
+    local config = tbl_deep_extend('keep', user_config, default_config)
 
     if util.on_setup then
-      pcall(util.on_setup, config)
+      pcall(util.on_setup, config, user_config)
     end
 
     if config.autostart == true then
diff --git a/test/lspconfig_spec.lua b/test/lspconfig_spec.lua
index f98568c1..8cea4a54 100644
--- a/test/lspconfig_spec.lua
+++ b/test/lspconfig_spec.lua
@@ -324,5 +324,23 @@ describe('lspconfig', function()
         { 'rust_analyzer' }
       )
     end)
+
+    it('provides user_config to the on_setup hook', function()
+      eq(
+        exec_lua [[
+        local lspconfig = require "lspconfig"
+        local util = require "lspconfig.util"
+        local user_config
+        util.on_setup = function (_, _user_config)
+          user_config = _user_config
+        end
+        lspconfig.rust_analyzer.setup { custom_user_config = "custom" }
+        return user_config
+      ]],
+        {
+          custom_user_config = 'custom',
+        }
+      )
+    end)
   end)
 end)