refactor: use LspAttach instead of calling on_attach

.github/update_readme.py

@@ -71,7 +71,7 @@ def update_treesitter_languages():
     languages = sorted(os.listdir(os.path.join(ROOT, "queries")))
     language_lines = ["\n"] + [f"- {l}\n" for l in languages] + ["\n"]
     replace_section(
-        README, r"^\s*<summary>Supported languages", r"^[^\s\-]", language_lines
+        README, r"^\s*<summary>Supported treesitter languages", r"^[^\s\-]", language_lines
     )
 
 

README.md

@@ -5,9 +5,6 @@ A code outline window for skimming and quick navigation
 - [Requirements](#requirements)
 - [Installation](#installation)
 - [Setup](#setup)
-  - [Treesitter](#treesitter)
-  - [LSP](#lsp)
-  - [Markdown](#markdown)
   - [Keymaps](#keymaps)
 - [Commands](#commands)
 - [Options](#options)
@@ -103,20 +100,10 @@ Somewhere in your init.lua you will need to call `aerial.setup()`. See below for
 require('aerial').setup({})
 ```
 
-In addition, you will need to follow the setup steps for at least one of the
-symbol sources listed below. You can configure your preferred source(s) with the
-`backends` option (see [Options](#options)). The default is to prefer Treesitter
-when it's available and fall back to LSP.
-
-### Treesitter
-
-First ensure you have
-[nvim-treesitter](https://github.com/nvim-treesitter/nvim-treesitter) installed
-and configured for all languages you want to support. That's all! Aerial will
-automatically fetch symbols from treesitter.
+In addition, you will need to have either Treesitter or a working LSP client. You can configure your preferred source(s) with the `backends` option (see [Options](#options)). The default is to prefer Treesitter when it's available and fall back to LSP.
 
 <details>
-  <summary>Supported languages</summary>
+  <summary>Supported treesitter languages</summary>
 
 - bash
 - c
@@ -153,40 +140,6 @@ it](https://github.com/stevearc/aerial.nvim/issues/new?assignees=stevearc&labels
 
 </details>
 
-### LSP
-
-First ensure you have a functioning LSP setup (see
-[nvim-lspconfig](https://github.com/neovim/nvim-lspconfig)). Once complete, add
-the aerial `on_attach` callback to your config:
-
-```lua
--- Set up your LSP clients here, using the aerial on_attach method
-require("lspconfig").vimls.setup{
-  on_attach = require("aerial").on_attach,
-}
--- Repeat this for each language server you have configured
-```
-
-If you have your own custom `on_attach` function, call aerial's `on_attach` from
-inside it:
-
-```lua
-local function my_custom_attach(client, bufnr)
-  -- your code here
-  require("aerial").on_attach(client, bufnr)
-end
-```
-
-### Markdown
-
-There is a simple custom backend that does rudimentary parsing of markdown
-headers. It should work well enough in most cases, but does not parse the full
-markdown spec.
-
-There is now an experimental [treesitter parser for
-markdown](https://github.com/nvim-treesitter/nvim-treesitter/issues/872), so you
-can install that and try the treesitter backend instead.
-
 ### Keymaps
 
 While not required, you may want to add some keymaps for aerial. The best way to

lua/aerial/backends/lsp/init.lua

@@ -71,26 +71,39 @@ M.fetch_symbols_sync = function(bufnr, opts)
   end
 end
 
-local function mark_lsp_attached(bufnr)
-  vim.api.nvim_buf_set_var(bufnr, "_aerial_lsp_attached", true)
+local function mark_lsp_attached(bufnr, attached)
+  vim.api.nvim_buf_set_var(bufnr, "_aerial_lsp_attached", attached)
 end
 
+---@param bufnr integer
+---@return boolean
 local function is_lsp_attached(bufnr)
   local ok, attached = pcall(vim.api.nvim_buf_get_var, bufnr, "_aerial_lsp_attached")
   return ok and attached
 end
 
+---@param bufnr integer
+---@param exclude_id nil|integer Client ID to exclude from calculation
+---@return boolean
+local function has_lsp_client(bufnr, exclude_id)
+  for _, client in pairs(vim.lsp.buf_get_clients(bufnr)) do
+    if client.id ~= exclude_id and client.server_capabilities.documentSymbolProvider then
+      return true
+    end
+  end
+  return false
+end
+
 M.is_supported = function(bufnr)
   if not bufnr or bufnr == 0 then
     bufnr = vim.api.nvim_get_current_buf()
   end
   if not is_lsp_attached(bufnr) then
-    for _, client in pairs(vim.lsp.buf_get_clients(bufnr)) do
-      if client.server_capabilities.documentSymbolProvider then
-        return false, "LSP client not attached (did you call aerial.on_attach?)"
-      end
+    if has_lsp_client(bufnr) then
+      return false, "LSP client available, but not attached"
+    else
+      return false, "No LSP client found"
     end
-    return false, "LSP client not attached"
   end
   return true, nil
 end
@@ -105,7 +118,14 @@ M.on_attach = function(client, bufnr, opts)
   opts = opts or {}
   if client.server_capabilities.documentSymbolProvider then
     hook_handlers(opts.preserve_callback)
-    mark_lsp_attached(bufnr)
+    mark_lsp_attached(bufnr, true)
+    backends.attach(bufnr, true)
+  end
+end
+
+M.on_detach = function(client_id, bufnr)
+  if not has_lsp_client(bufnr, client_id) then
+    mark_lsp_attached(bufnr, false)
     backends.attach(bufnr, true)
   end
 end

lua/aerial/init.lua

@@ -33,6 +33,23 @@ M.setup = function(opts)
       require("aerial.autocommands").on_enter_buffer()
     end,
   })
+  vim.api.nvim_create_autocmd("LspAttach", {
+    desc = "Aerial mark LSP backend as available",
+    pattern = "*",
+    group = group,
+    callback = function(args)
+      local client = vim.lsp.get_client_by_id(args.data.client_id)
+      require("aerial.backends.lsp").on_attach(client, args.buf)
+    end,
+  })
+  vim.api.nvim_create_autocmd("LspDetach", {
+    desc = "Aerial mark LSP backend as unavailable",
+    pattern = "*",
+    group = group,
+    callback = function(args)
+      require("aerial.backends.lsp").on_detach(args.data.client_id, args.buf)
+    end,
+  })
   command.create_commands()
   highlight.create_highlight_groups()
 end
@@ -127,9 +144,12 @@ M.up = function(direction, count)
   nav.up(direction, count)
 end
 
--- This LSP on_attach function must be called in order to use the LSP backend
+---@deprecated
 M.on_attach = function(...)
-  require("aerial.backends.lsp").on_attach(...)
+  vim.notify_once(
+    "Deprecated(aerial.on_attach): you no longer need to call this function\nThis function will be removed on 2023-02-01",
+    vim.log.levels.WARN
+  )
 end
 
 -- Returns a list representing the symbol path to the current location.
@@ -293,8 +313,8 @@ end
 
 -- Register a callback to be called when aerial is attached to a buffer.
 M.register_attach_cb = function(callback)
-  vim.notify(
-    "Deprecated(register_attach_cb): pass `on_attach` to aerial.setup() instead (see :help aerial)",
+  vim.notify_once(
+    "Deprecated(aerial.register_attach_cb): pass `on_attach` to aerial.setup() instead (see :help aerial)\nThis function will be removed on 2023-02-01",
     vim.log.levels.WARN
   )
   config.on_attach = callback