feat(lsp): vim.lsp.get_configs() #37237

Problem:
No way to iterate configs. Users need to reach
for `vim.lsp.config._configs`, an internal interface.

Solution:
Provide vim.lsp.get_configs().
Also indirectly improves :lsp enable/disable completion
by discarding invalid configs from completion.

runtime/doc/lsp.txt

@@ -1153,6 +1153,23 @@ get_clients({filter})                                  *vim.lsp.get_clients()*
     Return: ~
         (`vim.lsp.Client[]`) List of |vim.lsp.Client| objects
 
+get_configs({filter})                                  *vim.lsp.get_configs()*
+    Get LSP configs.
+
+    Note: Will eagerly evaluate config files in `'runtimepath'` if necessary.
+
+    Parameters: ~
+      • {filter}  (`table?`) Key-value pairs used to filter the returned
+                  configs.
+                  • {enabled}? (`boolean`) If true, only return enabled
+                    configs. If false, only return configs that aren't
+                    enabled.
+                  • {filetype}? (`string`) Only return configs which attach to
+                    the given filetype.
+
+    Return: ~
+        (`vim.lsp.Config[]`) List of |vim.lsp.Config| objects
+
 is_enabled({name})                                      *vim.lsp.is_enabled()*
     Checks if the given LSP config is enabled (globally, not per-buffer).
 

runtime/doc/news.txt

@@ -330,6 +330,7 @@ LSP
 • Support for `workspace/codeLens/refresh`:
   https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#codeLens_refresh
 • |gx| opens `textDocument/documentLink` items found at cursor.
+• |vim.lsp.get_configs()| can get all LSP configs matching certain conditions.
 
 LUA
 

runtime/lua/vim/_core/ex_cmd.lua

@@ -19,45 +19,22 @@ local function get_client_names()
     :totable()
 end
 
---- @return string[]
-local function get_config_names()
-  local config_names = vim
-    .iter(api.nvim_get_runtime_file('lsp/*.lua', true))
-    --- @param path string
-    :map(function(path)
-      local file_name = path:match('[^/]*.lua$')
-      return file_name:sub(0, #file_name - 4)
-    end)
-    :totable()
-
-  --- @diagnostic disable-next-line
-  vim.list_extend(config_names, vim.tbl_keys(lsp.config._configs))
-
-  return vim
-    .iter(config_names)
-    :unique()
-    --- @param name string
-    :filter(function(name)
-      return name ~= '*'
-    end)
-    :totable()
-end
-
---- @param filter fun(string):boolean
+--- @param filter vim.lsp.get_configs.Filter
 --- @return fun():string[]
 local function filtered_config_names(filter)
   return function()
-    return vim.iter(get_config_names()):filter(filter):totable()
+    return vim
+      .iter(lsp.get_configs(filter))
+      :map(function(config)
+        return config.name
+      end)
+      :totable()
   end
 end
 
 local complete_args = {
-  enable = filtered_config_names(function(name)
-    return not lsp.is_enabled(name)
-  end),
-  disable = filtered_config_names(function(name)
-    return lsp.is_enabled(name)
-  end),
+  enable = filtered_config_names { enabled = false },
+  disable = filtered_config_names { enabled = true },
   restart = get_client_names,
   stop = get_client_names,
 }
@@ -79,17 +56,10 @@ local function ex_lsp_enable(config_names)
   -- Default to enabling all clients matching the filetype of the current buffer.
   if #config_names == 0 then
     local filetype = vim.bo.filetype
-    for _, name in ipairs(get_config_names()) do
-      local success, result = pcall(function()
-        return lsp.config[name]
-      end)
-      if success then
-        local filetypes = result.filetypes
-        if filetypes == nil or vim.list_contains(filetypes, filetype) then
-          table.insert(config_names, name)
-        end
-      else
-        echo_err(result --[[@as string]])
+    for _, config in ipairs(lsp.get_configs()) do
+      local filetypes = config.filetypes
+      if filetypes == nil or vim.list_contains(filetypes, filetype) then
+        table.insert(config_names, config.name)
       end
     end
     if #config_names == 0 then

runtime/lua/vim/lsp.lua

@@ -387,6 +387,76 @@ lsp.config = setmetatable({ _configs = {} }, {
   end,
 })
 
+--- @return string[]
+local function get_config_names()
+  local config_names = vim
+    .iter(api.nvim_get_runtime_file('lsp/*.lua', true))
+    --- @param path string
+    :map(function(path)
+      local file_name = path:match('[^/]*.lua$')
+      return file_name:sub(0, #file_name - 4)
+    end)
+    :totable()
+
+  vim.list_extend(config_names, vim.tbl_keys(lsp.config._configs))
+
+  return vim
+    .iter(config_names)
+    :unique()
+    --- @param name string
+    :filter(function(name)
+      return name ~= '*'
+    end)
+    :totable()
+end
+
+--- Key-value pairs used to filter the returned configs.
+--- @class vim.lsp.get_configs.Filter
+--- @inlinedoc
+---
+--- If true, only return enabled configs. If false, only return configs that
+--- aren't enabled.
+--- @field enabled? boolean
+---
+--- Only return configs which attach to the given filetype.
+--- @field filetype? string
+
+--- Get LSP configs.
+---
+--- Note: Will eagerly evaluate config files in `'runtimepath'` if necessary.
+--- @param filter? vim.lsp.get_configs.Filter
+--- @return vim.lsp.Config[]: List of |vim.lsp.Config| objects
+function lsp.get_configs(filter)
+  validate('filter', filter, 'table', true)
+
+  filter = filter or {}
+
+  local configs = {} --- @type vim.lsp.Config[]
+
+  local config_names --- @type string[]
+  if not filter.enabled then
+    config_names = get_config_names()
+  else
+    -- Shortcut filtering enabled configs by directly getting enabled configs
+    config_names = vim.tbl_keys(lsp._enabled_configs)
+  end
+
+  for _, config_name in ipairs(config_names) do
+    local config = lsp.config[config_name]
+    if
+      config
+      and (filter.enabled ~= false or not lsp.is_enabled(config_name))
+      and (
+        filter.filetype == nil
+        or (config.filetypes ~= nil and vim.list_contains(config.filetypes, filter.filetype))
+      )
+    then
+      configs[#configs + 1] = config
+    end
+  end
+  return configs
+end
+
 local lsp_enable_autocmd_id --- @type integer?
 
 local function validate_cmd(v)

test/functional/plugin/lsp_spec.lua

@@ -7114,6 +7114,52 @@ describe('LSP', function()
       exec_lua([[vim.lsp.enable('foo', false)]])
       eq(false, exec_lua([[return vim.lsp.is_enabled('foo')]]))
     end)
+
+    it('vim.lsp.get_configs()', function()
+      exec_lua(function()
+        vim.lsp.config('foo', {
+          cmd = { 'foo' },
+          filetypes = { 'foofile' },
+          root_markers = { '.foorc' },
+        })
+        vim.lsp.config('bar', {
+          cmd = { 'bar' },
+          root_markers = { '.barrc' },
+        })
+        vim.lsp.enable('foo')
+      end)
+
+      local function names(configs)
+        local config_names = vim
+          .iter(configs)
+          :map(function(config)
+            return config.name
+          end)
+          :totable()
+        table.sort(config_names)
+        return config_names
+      end
+
+      -- With no filter, return all configs
+      eq({ 'bar', 'foo' }, names(exec_lua([[return vim.lsp.get_configs()]])))
+
+      -- Confirm `enabled` works
+      eq({ 'foo' }, names(exec_lua([[return vim.lsp.get_configs { enabled = true }]])))
+      eq({ 'bar' }, names(exec_lua([[return vim.lsp.get_configs { enabled = false }]])))
+
+      -- Confirm `filetype` works
+      eq({ 'foo' }, names(exec_lua([[return vim.lsp.get_configs { filetype = 'foofile' }]])))
+
+      -- Confirm filters combine
+      eq(
+        { 'foo' },
+        names(exec_lua([[return vim.lsp.get_configs { filetype = 'foofile', enabled = true }]]))
+      )
+      eq(
+        {},
+        names(exec_lua([[return vim.lsp.get_configs { filetype = 'foofile', enabled = false }]]))
+      )
+    end)
   end)
 
   describe('vim.lsp.buf.workspace_diagnostics()', function()