feat(statusline): add section_lsp() to show attached LSP servers

CHANGELOG.md

@@ -58,6 +58,7 @@
     - Fallback icon is "Diag" instead of "LSP".
 - BREAKING FEATURE: `section_git()` now prefers using data from 'mini.git' with fallback on pure HEAD data from 'lewis6991/gistigns.nvim'.
 - FEATURE: add `section_diff()` to show data from 'mini.diff' with fallback on diff data from 'lewis6991/gistigns.nvim'.
+- FEATURE: add `section_lsp()` to show indicator of LSP servers attached to the buffer.
 - BREAKING FEATURE: update default active content to use both `section_git()` and `section_diff()`.
 
 ## mini.tabline

doc/mini-statusline.txt

@@ -271,6 +271,21 @@ Parameters ~
 Return ~
 `(string)` Section string.
 
+------------------------------------------------------------------------------
+                                                  *MiniStatusline.section_lsp()*
+                      `MiniStatusline.section_lsp`({args})
+Section for attached LSP servers
+
+Shows number of LSP servers (each as separate "+" character) attached to
+current buffer or nothing if none is attached.
+Nothing is shown if window width is lower than `args.trunc_width`.
+
+Parameters ~
+{args} `(table)` Section arguments. Use `args.icon` to supply your own icon.
+
+Return ~
+`(string)` Section string.
+
 ------------------------------------------------------------------------------
                                              *MiniStatusline.section_filename()*
                    `MiniStatusline.section_filename`({args})

lua/mini/statusline.lua

@@ -335,6 +335,26 @@ MiniStatusline.section_diagnostics = function(args)
   return icon .. table.concat(t, '')
 end
 
+--- Section for attached LSP servers
+---
+--- Shows number of LSP servers (each as separate "+" character) attached to
+--- current buffer or nothing if none is attached.
+--- Nothing is shown if window width is lower than `args.trunc_width`.
+---
+---@param args __statusline_args Use `args.icon` to supply your own icon.
+---
+---@return __statusline_section
+MiniStatusline.section_lsp = function(args)
+  if MiniStatusline.is_truncated(args.trunc_width) then return '' end
+
+  local attached = H.get_attached_lsp()
+  if attached == '' then return '' end
+
+  local use_icons = H.use_icons or H.get_config().use_icons
+  local icon = args.icon or (use_icons and '󰰎' or 'LSP')
+  return icon .. ' ' .. attached
+end
+
 --- Section for file name
 ---
 --- Show full file name or relative in short output.
@@ -447,8 +467,8 @@ H.diagnostic_levels = {
   { name = 'HINT', sign = 'H' },
 }
 
--- Count of attached LSP clients per buffer id
-H.n_attached_lsp = {}
+-- String representation of attached LSP clients per buffer id
+H.attached_lsp = {}
 
 -- Helper functionality =======================================================
 -- Settings -------------------------------------------------------------------
@@ -497,11 +517,12 @@ H.create_autocommands = function()
   au({ 'WinEnter', 'BufWinEnter' }, '*', H.ensure_content, 'Ensure statusline content')
 
   if vim.fn.has('nvim-0.8') == 1 then
-    local make_track_lsp = function(increment)
-      return function(data) H.n_attached_lsp[data.buf] = (H.n_attached_lsp[data.buf] or 0) + increment end
-    end
-    au('LspAttach', '*', make_track_lsp(1), 'Track LSP clients')
-    au('LspDetach', '*', make_track_lsp(-1), 'Track LSP clients')
+    -- Use `schedule_wrap()` because at `LspDetach` server is still present
+    local track_lsp = vim.schedule_wrap(function(data)
+      H.attached_lsp[data.buf] = H.compute_attached_lsp(data.buf)
+      vim.cmd('redrawstatus')
+    end)
+    au({ 'LspAttach', 'LspDetach' }, '*', track_lsp, 'Track LSP clients')
   end
 end
 
@@ -601,6 +622,40 @@ end
 
 H.default_content_inactive = function() return '%#MiniStatuslineInactive#%F%=' end
 
+-- LSP ------------------------------------------------------------------------
+H.get_attached_lsp = function() return H.attached_lsp[vim.api.nvim_get_current_buf()] or '' end
+if vim.fn.has('nvim-0.8') == 0 then
+  H.get_attached_lsp = function() return H.compute_attached_lsp(vim.api.nvim_get_current_buf()) end
+end
+
+H.compute_attached_lsp = function(buf_id)
+  local names = vim.tbl_map(function() return '+' end, H.get_buf_lsp_clients(buf_id))
+  return table.concat(names, '')
+end
+
+H.get_buf_lsp_clients = function(buf_id) return vim.lsp.get_clients({ bufnr = buf_id }) end
+if vim.fn.has('nvim-0.10') == 0 then
+  H.get_buf_lsp_clients = function(buf_id) return vim.lsp.buf_get_clients(buf_id) end
+end
+
+-- Diagnostics ----------------------------------------------------------------
+H.diagnostic_get_count = function()
+  local res = {}
+  for _, d in ipairs(vim.diagnostic.get(0)) do
+    res[d.severity] = (res[d.severity] or 0) + 1
+  end
+  return res
+end
+if vim.fn.has('nvim-0.10') == 1 then H.diagnostic_get_count = function() return vim.diagnostic.count(0) end end
+
+if vim.fn.has('nvim-0.10') == 1 then
+  H.diagnostic_is_disabled = function(_) return not vim.diagnostic.is_enabled({ bufnr = 0 }) end
+elseif vim.fn.has('nvim-0.9') == 1 then
+  H.diagnostic_is_disabled = function(_) return vim.diagnostic.is_disabled(0) end
+else
+  H.diagnostic_is_disabled = function(_) return false end
+end
+
 -- Utilities ------------------------------------------------------------------
 H.get_filesize = function()
   local size = vim.fn.getfsize(vim.fn.getreg('%'))
@@ -625,24 +680,4 @@ H.ensure_get_icon = function()
   end
 end
 
-H.has_no_lsp_attached = function() return (H.n_attached_lsp[vim.api.nvim_get_current_buf()] or 0) == 0 end
-if vim.fn.has('nvim-0.8') == 0 then H.has_no_lsp_attached = function() return #vim.lsp.buf_get_clients() == 0 end end
-
-H.diagnostic_get_count = function()
-  local res = {}
-  for _, d in ipairs(vim.diagnostic.get(0)) do
-    res[d.severity] = (res[d.severity] or 0) + 1
-  end
-  return res
-end
-if vim.fn.has('nvim-0.10') == 1 then H.diagnostic_get_count = function() return vim.diagnostic.count(0) end end
-
-if vim.fn.has('nvim-0.10') == 1 then
-  H.diagnostic_is_disabled = function(_) return not vim.diagnostic.is_enabled({ bufnr = 0 }) end
-elseif vim.fn.has('nvim-0.9') == 1 then
-  H.diagnostic_is_disabled = function(_) return vim.diagnostic.is_disabled(0) end
-else
-  H.diagnostic_is_disabled = function(_) return false end
-end
-
 return MiniStatusline

tests/dir-statusline/mock-diagnostics.lua

@@ -1,9 +1,3 @@
-vim.lsp.buf_get_clients = function() return { 'mock client' } end
-if vim.fn.has('nvim-0.8') == 1 then
-  vim.api.nvim_exec_autocmds('LspAttach', { data = { client_id = 1 } })
-  _G.detach_lsp = function() vim.api.nvim_exec_autocmds('LspDetach', { data = { client_id = 1 } }) end
-end
-
 vim.diagnostic.get = function(_, _)
   local s = vim.diagnostic.severity
   return {

tests/dir-statusline/mock-lsp.lua

@@ -0,0 +1,27 @@
+_G.n_lsp_clients = 0
+local mock_buf_clients = function()
+  local res = {}
+  for i = 1, _G.n_lsp_clients do
+    res[i] = { id = i }
+  end
+  return res
+end
+vim.lsp.buf_get_clients = mock_buf_clients
+vim.lsp.get_clients = mock_buf_clients
+
+_G.attach_lsp = function()
+  _G.n_lsp_clients = _G.n_lsp_clients + 1
+  if vim.fn.has('nvim-0.8') == 1 then
+    vim.api.nvim_exec_autocmds('LspAttach', { data = { client_id = _G.n_lsp_clients } })
+  end
+end
+
+_G.detach_lsp = function()
+  local n = _G.n_lsp_clients
+  if n == 0 then return end
+
+  _G.n_lsp_clients = _G.n_lsp_clients - 1
+  if vim.fn.has('nvim-0.8') == 1 then vim.api.nvim_exec_autocmds('LspDetach', { data = { client_id = n } }) end
+end
+
+_G.attach_lsp()

tests/test_statusline.lua

@@ -47,6 +47,8 @@ local mock_minidiff = function() child.b.minidiff_summary_string = '#4 +3 ~2 -1'
 
 local mock_diagnostics = function() child.cmd('luafile tests/dir-statusline/mock-diagnostics.lua') end
 
+local mock_lsp = function() child.cmd('luafile tests/dir-statusline/mock-lsp.lua') end
+
 local mocked_filepath = vim.fn.fnamemodify('tests/dir-statusline/mocked.lua', ':p')
 local mock_file = function(bytes)
   -- Reduce one byte for '\n' at end
@@ -308,8 +310,12 @@ T['section_diagnostics()']['works'] = function()
   eq(child.lua_get('MiniStatusline.section_diagnostics({})'), ' E4 W3 I2 H1')
 
   -- Should not depend on LSP server attached
-  child.lua('vim.lsp.buf_get_clients = function() return {} end')
-  if child.fn.has('nvim-0.8') == 1 then child.lua('_G.detach_lsp()') end
+  mock_lsp()
+  eq(child.lua_get('_G.n_lsp_clients'), 1)
+  eq(child.lua_get('MiniStatusline.section_diagnostics({})'), ' E4 W3 I2 H1')
+
+  child.lua('_G.detach_lsp()')
+  eq(child.lua_get('_G.n_lsp_clients'), 0)
   eq(child.lua_get('MiniStatusline.section_diagnostics({})'), ' E4 W3 I2 H1')
 
   -- Should return empty string if no diagnostic entries defined
@@ -363,6 +369,42 @@ T['section_diagnostics()']['is not shown if diagnostics is disabled'] = function
   eq(child.lua_get('MiniStatusline.section_diagnostics({})'), '')
 end
 
+T['section_lsp()'] = new_set({ hooks = { pre_case = mock_lsp } })
+
+T['section_lsp()']['works'] = function()
+  eq(child.lua_get('MiniStatusline.section_lsp({})'), '󰰎 +')
+
+  -- Should show number of attached LSP servers
+  child.lua('_G.attach_lsp()')
+  eq(child.lua_get('MiniStatusline.section_lsp({})'), '󰰎 ++')
+
+  -- Should show empty string if no attached LSP servers
+  child.lua('_G.detach_lsp()')
+  child.lua('_G.detach_lsp()')
+  eq(child.lua_get('MiniStatusline.section_lsp({})'), '')
+end
+
+T['section_lsp()']['respects `args.trunc_width`'] = function()
+  set_width(100)
+  eq(child.lua_get('MiniStatusline.section_lsp({ trunc_width = 100 })'), '󰰎 +')
+  set_width(99)
+  eq(child.lua_get('MiniStatusline.section_lsp({ trunc_width = 100 })'), '')
+end
+
+T['section_lsp()']['respects `args.icon`'] = function()
+  eq(child.lua_get([[MiniStatusline.section_lsp({icon = 'A'})]]), 'A +')
+  eq(child.lua_get([[MiniStatusline.section_lsp({icon = 'AAA'})]]), 'AAA +')
+end
+
+T['section_lsp()']['respects `config.use_icons`'] = function()
+  child.lua('MiniStatusline.config.use_icons = false')
+  eq(child.lua_get([[MiniStatusline.section_lsp({})]]), 'LSP +')
+
+  -- Should also use buffer local config
+  child.b.ministatusline_config = { use_icons = true }
+  eq(child.lua_get([[MiniStatusline.section_lsp({})]]), '󰰎 +')
+end
+
 T['section_fileinfo()'] = new_set({ hooks = { pre_case = mock_devicons, post_case = unmock_file } })
 
 local validate_fileinfo = function(args, pattern)