feat: expose config definition as `config_def` #3335

Problem:
Users/plugins may want to use the config definition without actually
activating the config via setup().

Solution:
- Expose `config_def` field and document it.
- Also undeprecate some stuff that doesn't yet have a documented
  alternative.

TODO: configs.lua sets `M.filetypes = config.filetypes` and other fields
in ad-hoc fashion "for :LspInfo" but it's not clear when those fields
are actually populated, and they don't source from `config_def`...

2 files changed, 8 insertions, 3 deletions

diff --git a/lua/lspconfig/configs.lua b/lua/lspconfig/configs.lua
index 5a5fc2e5..e8271636 100644
--- a/lua/lspconfig/configs.lua
+++ b/lua/lspconfig/configs.lua
@@ -26,6 +26,9 @@ local function sanitize_cmd(cmd)
   end
 end
 
+---@param t table
+---@param config_name string
+---@param config_def table Config definition read from `lspconfig.configs.<name>`.
 function configs.__newindex(t, config_name, config_def)
   validate {
     name = { config_name, 's' },
@@ -178,7 +181,7 @@ function configs.__newindex(t, config_name, config_def)
       end)
     end
 
-    -- Used by :LspInfo
+    -- Used by :LspInfo (evil, mutable aliases?)
     M.get_root_dir = get_root_dir
     M.filetypes = config.filetypes
     M.handlers = config.handlers
@@ -290,7 +293,9 @@ function configs.__newindex(t, config_name, config_def)
 
   M.commands = config_def.commands
   M.name = config_name
-  M.document_config = config_def
+  -- Expose the (original?) values of a config (non-active, or before `setup()`).
+  M.config_def = config_def
+  M.document_config = config_def -- For back-compat.
 
   rawset(t, config_name, M)
 end
diff --git a/lua/lspconfig/ui/lspinfo.lua b/lua/lspconfig/ui/lspinfo.lua
index e0b9bf96..cc1e1b56 100644
--- a/lua/lspconfig/ui/lspinfo.lua
+++ b/lua/lspconfig/ui/lspinfo.lua
@@ -329,7 +329,7 @@ return function()
       if not config then
         return
       end
-      local desc = vim.tbl_get(config, 'document_config', 'docs', 'description')
+      local desc = vim.tbl_get(config, 'config_def', 'docs', 'description')
       if desc then
         lines[#lines + 1] = string.format('# %s', config.name)
         lines[#lines + 1] = ''