feat: Better provider info and fix LSP deprecated warnings

- Provider priorities can now be configured through `providers.priority`

- Each provider can have a get_status() function that returns a string
  for its status. For LSP it returns the client name.

- :OutlineStatus logic refactored, together with provider checking
  functions in `providers/init.lua`

- Switch from vim.lsp.buf_get_clients to vim.lsp.get_active_clients
  (former was deprecated)

- Fixed a careless mistake from symbols-outline that seems to be an
  unreachable bug (lsp)

lua/outline/config.lua

@@ -71,6 +71,7 @@ M.defaults = {
     up_and_jump = '<C-k>',
   },
   providers = {
+    priority = { 'lsp', 'coc', 'markdown' },
     lsp = {
       blacklist_clients = {},
     },
@@ -182,14 +183,35 @@ function M.is_symbol_blacklisted(kind)
   return has_value(M.o.symbols.blacklist, kind)
 end
 
-function M.is_client_blacklisted(client_id)
-  local client = vim.lsp.get_client_by_id(client_id)
+---@param client vim.lsp.client|number
+function M.is_client_blacklisted(client)
   if not client then
     return false
   end
+  if type(client) == 'number' then
+    client = vim.lsp.get_client_by_id(client)
+    if not client then
+      return false
+    end
+  end
   return has_value(M.o.providers.lsp.blacklist_clients, client.name)
 end
 
+function M.get_providers()
+  if M.providers then
+    return M.providers
+  end
+
+  M.providers = {}
+  for _, p in ipairs(M.o.providers.priority) do
+    if p == 'lsp' then
+      p = 'nvim-lsp' -- due to legacy reasons
+    end
+    table.insert(M.providers, p)
+  end
+  return M.providers
+end
+
 function M.show_help()
   print 'Current keymaps:'
   print(vim.inspect(M.o.keymaps))

lua/outline/init.lua

@@ -606,32 +606,50 @@ end
 
 ---Display outline window status in the message area.
 function M.show_status()
-  if M.has_provider() then
-    print("Current provider:")
-    print('  ' .. _G._outline_current_provider.name)
+  -- TODO: Use a floating window instead
+  local p = _G._outline_current_provider
+  if not M.is_active() then
+    p = providers.find_provider()
+  end
+
+  if p ~= nil then
+    print("Current provider: " .. p.name)
+    if p.get_status then
+      print(p.get_status())
+      print()
+    end
+
     if M.view:is_open() then
       print("Outline window is open.")
     else
       print("Outline window is not open.")
     end
+
     if require('outline.preview').has_code_win() then
       print("Code window is active.")
     else
-      print("Warning: code window is either closed or invalid. Please close and reopen the outline window.")
+      print("Code window is either closed or invalid. Please close and reopen the outline window.")
     end
   else
     print("No providers")
   end
 end
 
+function M.is_active()
+  local winid = vim.fn.win_getid()
+  if M.view:is_open() and winid == M.view.winnr then
+    return true
+  end
+  return false
+end
+
 ---Whether there is currently an available provider.
 ---@return boolean has_provider
 function M.has_provider()
-  local winid = vim.fn.win_getid()
-  if M.view:is_open() and winid == M.view.winnr then
+  if M.is_active() then
     return _G._outline_current_provider ~= nil
   end
-  return providers.has_provider() and _G._outline_current_provider
+  return providers.has_provider()
 end
 
 local function setup_commands()

lua/outline/providers/coc.lua

@@ -1,4 +1,7 @@
-local M = {}
+local M = {
+  name = 'coc',
+}
+
 
 function M.should_use_provider(_)
   local not_coc_installed = vim.fn.exists '*CocActionAsync' == 0

lua/outline/providers/init.lua

@@ -1,44 +1,43 @@
-local M = {}
+local cfg = require "outline.config"
 
--- NOTE: There is in fact a markdown LSP that can provide symbols. However on
--- buffer open the LSP may not be attached immediately. Before the LSP is ready
--- if the user opens the outline, our own markdown provider will be used. After
--- refreshing/reopening, the provider will then switch to the LSP (if the user
--- has a markdown LSP).
-local providers = {
-  'outline/providers/nvim-lsp',
-  'outline/providers/coc',
-  'outline/providers/markdown',
-}
+local M = {}
+local import_prefix = "outline/providers/"
 
 _G._outline_current_provider = nil
 
-function M.has_provider()
-  local ret = false
-  for _, value in ipairs(providers) do
-    local provider = require(value)
+
+function M.find_provider()
+  if not M.providers then
+    M.providers = vim.tbl_map(function(p) return import_prefix..p end, cfg.get_providers())
+  end
+  for _, name in ipairs(M.providers) do
+    local provider = require(name)
     if provider.should_use_provider(0) then
-      ret = true
-      break
+      return provider, name
     end
   end
-  return ret
+  return nil, nil
+end
+
+---@return boolean found_provider
+function M.has_provider()
+  return M.find_provider() ~= nil
 end
 
 ---@param on_symbols function
 ---@param opts outline.OutlineOpts?
 ---@return boolean found_provider
 function M.request_symbols(on_symbols, opts)
-  for _, value in ipairs(providers) do
-    local provider = require(value)
-    if provider.should_use_provider(0) then
-      _G._outline_current_provider = provider
-      _G._outline_current_provider.name = value
-      provider.request_symbols(on_symbols, opts)
-      return true
-    end
+  local provider, name = M.find_provider()
+  if not provider then
+    return false
   end
-  return false
+  _G._outline_current_provider = provider
+  if not provider.name then
+    _G._outline_current_provider.name = name
+  end
+  provider.request_symbols(on_symbols, opts)
+  return true
 end
 
 return M

lua/outline/providers/markdown.lua

@@ -1,9 +1,20 @@
+-- NOTE
 -- Our own markdown provider is used because legacy symbols-outline considered
 -- the case where markdown does not have an LSP. However, it does, so as of now
 -- this module is kept for use when user opens symbols outline before the
--- markdown LSP is ready. Please also see comment in providers/init.lua
+-- markdown LSP is ready.
+--
+-- On buffer open the LSP may not be attached immediately. Before the LSP is
+-- ready if the user opens the outline, our own markdown provider will be used.
+-- After refreshing/reopening, the provider will then switch to the LSP (if the
+-- user has a markdown LSP). That is, if the user has an applicable markdown LSP.
+--
+-- If they don't this provider will always work as usual.
+
+local M = {
+  name = 'markdown',
+}
 
-local M = {}
 
 ---@return boolean ft_is_markdown
 function M.should_use_provider(bufnr)

lua/outline/providers/nvim-lsp.lua

@@ -2,50 +2,63 @@ local config = require 'outline.config'
 local lsp_utils = require 'outline.utils.lsp_utils'
 local jsx = require 'outline.utils.jsx'
 
-local M = {}
+local M = {
+  name = 'lsp',
+  ---@type vim.lsp.client
+  client = nil,
+}
 
-local function getParams()
+function M.get_status()
+  if not M.client then
+    return "No clients"
+  end
+  return "client: "..M.client.name
+end
+
+local function get_params()
   return { textDocument = vim.lsp.util.make_text_document_params() }
 end
 
 function M.hover_info(bufnr, params, on_info)
-  local clients = vim.lsp.buf_get_clients(bufnr)
-  local used_client
+  local clients = vim.lsp.get_active_clients({ bufnr = bufnr })
+  local use_client
 
-  for id, client in pairs(clients) do
-    if config.is_client_blacklisted(id) then
+  for _, client in ipairs(clients) do
+    if config.is_client_blacklisted(client) then
       goto continue
     else
       if client.server_capabilities.hoverProvider then
-        used_client = client
+        use_client = client
+        M.client = client
         break
       end
     end
     ::continue::
   end
 
-  if not used_client then
+  if not use_client then
     on_info(nil, {
       contents = {
         kind = 'markdown',
-        content = { 'No extra information availaible!' },
+        content = { 'No extra information availaible' },
       },
     })
+    return
   end
 
-  used_client.request('textDocument/hover', params, on_info, bufnr)
+  use_client.request('textDocument/hover', params, on_info, bufnr)
 end
 
--- probably change this
 function M.should_use_provider(bufnr)
-  local clients = vim.lsp.buf_get_clients(bufnr)
+  local clients = vim.lsp.get_active_clients({ bufnr = bufnr })
   local ret = false
 
-  for id, client in pairs(clients) do
-    if config.is_client_blacklisted(id) then
+  for _, client in ipairs(clients) do
+    if config.is_client_blacklisted(client) then
       goto continue
     else
       if client.server_capabilities.documentSymbolProvider then
+        M.client = client
         ret = true
         break
       end
@@ -73,7 +86,7 @@ function M.request_symbols(on_symbols, opts)
   vim.lsp.buf_request_all(
     0,
     'textDocument/documentSymbol',
-    getParams(),
+    get_params(),
     function (response)
       response = M.postprocess_symbols(response)
       on_symbols(response, opts)