Revert "feat(lsp): implement workspace/didChangeWatchedFiles (#21293)"

This reverts commit 5732aa706c639b3d775573d91d1139f24624629c.

Causes editor to freeze in projects with many watcher registrations

5 files changed, 9 insertions, 487 deletions

diff --git a/runtime/lua/vim/_editor.lua b/runtime/lua/vim/_editor.lua
index 92444ff550..3f27e61810 100644
--- a/runtime/lua/vim/_editor.lua
+++ b/runtime/lua/vim/_editor.lua
@@ -37,7 +37,6 @@ for k, v in pairs({
   health = true,
   fs = true,
   secure = true,
-  _watch = true,
 }) do
   vim._submodules[k] = v
 end
diff --git a/runtime/lua/vim/_watch.lua b/runtime/lua/vim/_watch.lua
deleted file mode 100644
index dba1522ec8..0000000000
--- a/runtime/lua/vim/_watch.lua
+++ /dev/null
@@ -1,174 +0,0 @@
-local M = {}
-
---- Enumeration describing the types of events watchers will emit.
-M.FileChangeType = vim.tbl_add_reverse_lookup({
-  Created = 1,
-  Changed = 2,
-  Deleted = 3,
-})
-
----@private
---- Joins filepath elements by static '/' separator
----
----@param ... (string) The path elements.
-local function filepath_join(...)
-  return table.concat({ ... }, '/')
-end
-
----@private
---- Stops and closes a libuv |uv_fs_event_t| or |uv_fs_poll_t| handle
----
----@param handle (uv_fs_event_t|uv_fs_poll_t) The handle to stop
-local function stop(handle)
-  local _, stop_err = handle:stop()
-  assert(not stop_err, stop_err)
-  local is_closing, close_err = handle:is_closing()
-  assert(not close_err, close_err)
-  if not is_closing then
-    handle:close()
-  end
-end
-
---- Initializes and starts a |uv_fs_event_t|
----
----@param path (string) The path to watch
----@param opts (table|nil) Additional options
----     - uvflags (table|nil)
----                Same flags as accepted by |uv.fs_event_start()|
----@param callback (function) The function called when new events
----@returns (function) A function to stop the watch
-function M.watch(path, opts, callback)
-  vim.validate({
-    path = { path, 'string', false },
-    opts = { opts, 'table', true },
-    callback = { callback, 'function', false },
-  })
-
-  path = vim.fs.normalize(path)
-  local uvflags = opts and opts.uvflags or {}
-  local handle, new_err = vim.loop.new_fs_event()
-  assert(not new_err, new_err)
-  local _, start_err = handle:start(path, uvflags, function(err, filename, events)
-    assert(not err, err)
-    local fullpath = path
-    if filename then
-      filename = filename:gsub('\\', '/')
-      fullpath = filepath_join(fullpath, filename)
-    end
-    local change_type = events.change and M.FileChangeType.Changed or 0
-    if events.rename then
-      local _, staterr, staterrname = vim.loop.fs_stat(fullpath)
-      if staterrname == 'ENOENT' then
-        change_type = M.FileChangeType.Deleted
-      else
-        assert(not staterr, staterr)
-        change_type = M.FileChangeType.Created
-      end
-    end
-    callback(fullpath, change_type)
-  end)
-  assert(not start_err, start_err)
-  return function()
-    stop(handle)
-  end
-end
-
-local default_poll_interval_ms = 2000
-
----@private
---- Implementation for poll, hiding internally-used parameters.
----
----@param watches (table|nil) A tree structure to maintain state for recursive watches.
----     - handle (uv_fs_poll_t)
----               The libuv handle
----     - cancel (function)
----               A function that cancels the handle and all children's handles
----     - is_dir (boolean)
----               Indicates whether the path is a directory (and the poll should
----               be invoked recursively)
----     - children (table|nil)
----               A mapping of directory entry name to its recursive watches
-local function poll_internal(path, opts, callback, watches)
-  path = vim.fs.normalize(path)
-  local interval = opts and opts.interval or default_poll_interval_ms
-  watches = watches or {
-    is_dir = true,
-  }
-
-  if not watches.handle then
-    local poll, new_err = vim.loop.new_fs_poll()
-    assert(not new_err, new_err)
-    watches.handle = poll
-    local _, start_err = poll:start(
-      path,
-      interval,
-      vim.schedule_wrap(function(err)
-        if err == 'ENOENT' then
-          return
-        end
-        assert(not err, err)
-        poll_internal(path, opts, callback, watches)
-        callback(path, M.FileChangeType.Changed)
-      end)
-    )
-    assert(not start_err, start_err)
-    callback(path, M.FileChangeType.Created)
-  end
-
-  watches.cancel = function()
-    if watches.children then
-      for _, w in pairs(watches.children) do
-        w.cancel()
-      end
-    end
-    stop(watches.handle)
-  end
-
-  if watches.is_dir then
-    watches.children = watches.children or {}
-    local exists = {}
-    for name, ftype in vim.fs.dir(path) do
-      exists[name] = true
-      if not watches.children[name] then
-        watches.children[name] = {
-          is_dir = ftype == 'directory',
-        }
-        poll_internal(filepath_join(path, name), opts, callback, watches.children[name])
-      end
-    end
-
-    local newchildren = {}
-    for name, watch in pairs(watches.children) do
-      if exists[name] then
-        newchildren[name] = watch
-      else
-        watch.cancel()
-        watches.children[name] = nil
-        callback(path .. '/' .. name, M.FileChangeType.Deleted)
-      end
-    end
-    watches.children = newchildren
-  end
-
-  return watches.cancel
-end
-
---- Initializes and starts a |uv_fs_poll_t| recursively watching every file underneath the
---- directory at path.
----
----@param path (string) The path to watch. Must refer to a directory.
----@param opts (table|nil) Additional options
----     - interval (number|nil)
----                Polling interval in ms as passed to |uv.fs_poll_start()|. Defaults to 2000.
----@param callback (function) The function called when new events
----@returns (function) A function to stop the watch.
-function M.poll(path, opts, callback)
-  vim.validate({
-    path = { path, 'string', false },
-    opts = { opts, 'table', true },
-    callback = { callback, 'function', false },
-  })
-  return poll_internal(path, opts, callback, nil)
-end
-
-return M
diff --git a/runtime/lua/vim/lsp/_watchfiles.lua b/runtime/lua/vim/lsp/_watchfiles.lua
deleted file mode 100644
index b9268b963c..0000000000
--- a/runtime/lua/vim/lsp/_watchfiles.lua
+++ /dev/null
@@ -1,274 +0,0 @@
-local bit = require('bit')
-local watch = require('vim._watch')
-local protocol = require('vim.lsp.protocol')
-
-local M = {}
-
----@private
----Parses the raw pattern into a number of Lua-native patterns.
----
----@param pattern string The raw glob pattern
----@return table A list of Lua patterns. A match with any of them matches the input glob pattern.
-local function parse(pattern)
-  local patterns = { '' }
-
-  local path_sep = '[/\\]'
-  local non_path_sep = '[^/\\]'
-
-  local function append(chunks)
-    local new_patterns = {}
-    for _, p in ipairs(patterns) do
-      for _, chunk in ipairs(chunks) do
-        table.insert(new_patterns, p .. chunk)
-      end
-    end
-    patterns = new_patterns
-  end
-
-  local function split(s, sep)
-    local segments = {}
-    local segment = ''
-    local in_braces = false
-    local in_brackets = false
-    for i = 1, #s do
-      local c = string.sub(s, i, i)
-      if c == sep and not in_braces and not in_brackets then
-        table.insert(segments, segment)
-        segment = ''
-      else
-        if c == '{' then
-          in_braces = true
-        elseif c == '}' then
-          in_braces = false
-        elseif c == '[' then
-          in_brackets = true
-        elseif c == ']' then
-          in_brackets = false
-        end
-        segment = segment .. c
-      end
-    end
-    if segment ~= '' then
-      table.insert(segments, segment)
-    end
-    return segments
-  end
-
-  local function escape(c)
-    if
-      c == '?'
-      or c == '.'
-      or c == '('
-      or c == ')'
-      or c == '%'
-      or c == '['
-      or c == ']'
-      or c == '*'
-      or c == '+'
-      or c == '-'
-    then
-      return '%' .. c
-    end
-    return c
-  end
-
-  local segments = split(pattern, '/')
-  for i, segment in ipairs(segments) do
-    local last_seg = i == #segments
-    if segment == '**' then
-      local chunks = {
-        path_sep .. '-',
-        '.-' .. path_sep,
-      }
-      if last_seg then
-        chunks = { '.-' }
-      end
-      append(chunks)
-    else
-      local in_braces = false
-      local brace_val = ''
-      local in_brackets = false
-      local bracket_val = ''
-      for j = 1, #segment do
-        local char = string.sub(segment, j, j)
-        if char ~= '}' and in_braces then
-          brace_val = brace_val .. char
-        else
-          if in_brackets and (char ~= ']' or bracket_val == '') then
-            local res
-            if char == '-' then
-              res = char
-            elseif bracket_val == '' and char == '!' then
-              res = '^'
-            elseif char == '/' then
-              res = ''
-            else
-              res = escape(char)
-            end
-            bracket_val = bracket_val .. res
-          else
-            if char == '{' then
-              in_braces = true
-            elseif char == '[' then
-              in_brackets = true
-            elseif char == '}' then
-              local choices = split(brace_val, ',')
-              local parsed_choices = {}
-              for _, choice in ipairs(choices) do
-                table.insert(parsed_choices, parse(choice))
-              end
-              append(vim.tbl_flatten(parsed_choices))
-              in_braces = false
-              brace_val = ''
-            elseif char == ']' then
-              append({ '[' .. bracket_val .. ']' })
-              in_brackets = false
-              bracket_val = ''
-            elseif char == '?' then
-              append({ non_path_sep })
-            elseif char == '*' then
-              append({ non_path_sep .. '-' })
-            else
-              append({ escape(char) })
-            end
-          end
-        end
-      end
-
-      if not last_seg and (segments[i + 1] ~= '**' or i + 1 < #segments) then
-        append({ path_sep })
-      end
-    end
-  end
-
-  return patterns
-end
-
----@private
---- Implementation of LSP 3.17.0's pattern matching: https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#pattern
---- Modeled after VSCode's implementation: https://github.com/microsoft/vscode/blob/0319eed971719ad48e9093daba9d65a5013ec5ab/src/vs/base/common/glob.ts#L509
----
----@param pattern string|table The glob pattern (raw or parsed) to match.
----@param s string The string to match against pattern.
----@return boolean Whether or not pattern matches s.
-function M._match(pattern, s)
-  if type(pattern) == 'string' then
-    pattern = parse(pattern)
-  end
-  -- Since Lua's built-in string pattern matching does not have an alternate
-  -- operator like '|', `parse` will construct one pattern for each possible
-  -- alternative. Any pattern that matches thus matches the glob.
-  for _, p in ipairs(pattern) do
-    if s:match('^' .. p .. '$') then
-      return true
-    end
-  end
-  return false
-end
-
-M._watchfunc = (vim.fn.has('win32') == 1 or vim.fn.has('mac') == 1) and watch.watch or watch.poll
-
----@type table<number, table<number, function()>> client id -> registration id -> cancel function
-local cancels = vim.defaulttable()
-
-local queue_timeout_ms = 100
----@type table<number, uv_timer_t> client id -> libuv timer which will send queued changes at its timeout
-local queue_timers = {}
----@type table<number, lsp.FileEvent[]> client id -> set of queued changes to send in a single LSP notification
-local change_queues = {}
----@type table<number, table<string, lsp.FileChangeType>> client id -> URI -> last type of change processed
---- Used to prune consecutive events of the same type for the same file
-local change_cache = vim.defaulttable()
-
-local to_lsp_change_type = {
-  [watch.FileChangeType.Created] = protocol.FileChangeType.Created,
-  [watch.FileChangeType.Changed] = protocol.FileChangeType.Changed,
-  [watch.FileChangeType.Deleted] = protocol.FileChangeType.Deleted,
-}
-
---- Registers the workspace/didChangeWatchedFiles capability dynamically.
----
----@param reg table LSP Registration object.
----@param ctx table Context from the |lsp-handler|.
-function M.register(reg, ctx)
-  local client_id = ctx.client_id
-  local client = vim.lsp.get_client_by_id(client_id)
-  for _, w in ipairs(reg.registerOptions.watchers) do
-    local glob_patterns = {}
-    if type(w.globPattern) == 'string' then
-      for _, folder in ipairs(client.workspace_folders) do
-        table.insert(glob_patterns, { baseUri = folder.uri, pattern = w.globPattern })
-      end
-    else
-      table.insert(glob_patterns, w.globPattern)
-    end
-    for _, glob_pattern in ipairs(glob_patterns) do
-      local pattern = parse(glob_pattern.pattern)
-      local base_dir = nil
-      if type(glob_pattern.baseUri) == 'string' then
-        base_dir = glob_pattern.baseUri
-      elseif type(glob_pattern.baseUri) == 'table' then
-        base_dir = glob_pattern.baseUri.uri
-      end
-      assert(base_dir, "couldn't identify root of watch")
-      base_dir = vim.uri_to_fname(base_dir)
-      local kind = w.kind
-        or protocol.WatchKind.Create + protocol.WatchKind.Change + protocol.WatchKind.Delete
-
-      table.insert(
-        cancels[client_id][reg.id],
-        M._watchfunc(base_dir, { uvflags = { recursive = true } }, function(fullpath, change_type)
-          change_type = to_lsp_change_type[change_type]
-          -- e.g. match kind with Delete bit (0b0100) to Delete change_type (3)
-          local kind_mask = bit.lshift(1, change_type - 1)
-          local change_type_match = bit.band(kind, kind_mask) == kind_mask
-          if not M._match(pattern, fullpath) or not change_type_match then
-            return
-          end
-
-          local change = {
-            uri = vim.uri_from_fname(fullpath),
-            type = change_type,
-          }
-
-          local last_type = change_cache[client_id][change.uri]
-          if last_type ~= change.type then
-            change_queues[client_id] = change_queues[client_id] or {}
-            table.insert(change_queues[client_id], change)
-            change_cache[client_id][change.uri] = change.type
-          end
-
-          if not queue_timers[client_id] then
-            queue_timers[client_id] = vim.defer_fn(function()
-              client.notify('workspace/didChangeWatchedFiles', {
-                changes = change_queues[client_id],
-              })
-              queue_timers[client_id] = nil
-              change_queues[client_id] = nil
-              change_cache[client_id] = nil
-            end, queue_timeout_ms)
-          end
-        end)
-      )
-    end
-  end
-end
-
---- Unregisters the workspace/didChangeWatchedFiles capability dynamically.
----
----@param unreg table LSP Unregistration object.
----@param ctx table Context from the |lsp-handler|.
-function M.unregister(unreg, ctx)
-  local client_id = ctx.client_id
-  local client_cancels = cancels[client_id]
-  local reg_cancels = client_cancels[unreg.id]
-  while #reg_cancels > 0 do
-    table.remove(reg_cancels)()
-  end
-  client_cancels[unreg.id] = nil
-  if not next(cancels[client_id]) then
-    cancels[client_id] = nil
-  end
-end
-
-return M
diff --git a/runtime/lua/vim/lsp/handlers.lua b/runtime/lua/vim/lsp/handlers.lua
index ee5b63d260..5096100a60 100644
--- a/runtime/lua/vim/lsp/handlers.lua
+++ b/runtime/lua/vim/lsp/handlers.lua
@@ -117,35 +117,15 @@ M['window/showMessageRequest'] = function(_, result)
 end
 
 --see: https://microsoft.github.io/language-server-protocol/specifications/specification-current/#client_registerCapability
-M['client/registerCapability'] = function(_, result, ctx)
-  local log_unsupported = false
-  for _, reg in ipairs(result.registrations) do
-    if reg.method == 'workspace/didChangeWatchedFiles' then
-      require('vim.lsp._watchfiles').register(reg, ctx)
-    else
-      log_unsupported = true
-    end
-  end
-  if log_unsupported then
-    local client_id = ctx.client_id
-    local warning_tpl = 'The language server %s triggers a registerCapability '
-      .. 'handler despite dynamicRegistration set to false. '
-      .. 'Report upstream, this warning is harmless'
-    local client = vim.lsp.get_client_by_id(client_id)
-    local client_name = client and client.name or string.format('id=%d', client_id)
-    local warning = string.format(warning_tpl, client_name)
-    log.warn(warning)
-  end
-  return vim.NIL
-end
-
---see: https://microsoft.github.io/language-server-protocol/specifications/specification-current/#client_unregisterCapability
-M['client/unregisterCapability'] = function(_, result, ctx)
-  for _, unreg in ipairs(result.unregisterations) do
-    if unreg.method == 'workspace/didChangeWatchedFiles' then
-      require('vim.lsp._watchfiles').unregister(unreg, ctx)
-    end
-  end
+M['client/registerCapability'] = function(_, _, ctx)
+  local client_id = ctx.client_id
+  local warning_tpl = 'The language server %s triggers a registerCapability '
+    .. 'handler despite dynamicRegistration set to false. '
+    .. 'Report upstream, this warning is harmless'
+  local client = vim.lsp.get_client_by_id(client_id)
+  local client_name = client and client.name or string.format('id=%d', client_id)
+  local warning = string.format(warning_tpl, client_name)
+  log.warn(warning)
   return vim.NIL
 end
 
diff --git a/runtime/lua/vim/lsp/protocol.lua b/runtime/lua/vim/lsp/protocol.lua
index df1ab26667..12345b6c8c 100644
--- a/runtime/lua/vim/lsp/protocol.lua
+++ b/runtime/lua/vim/lsp/protocol.lua
@@ -28,10 +28,6 @@ end
 ---@class lsp.MessageActionItem
 ---@field title string
 
----@class lsp.FileEvent
----@field uri string
----@field type lsp.FileChangeType
-
 local constants = {
   DiagnosticSeverity = {
     -- Reports an error.
@@ -64,7 +60,6 @@ local constants = {
   },
 
   -- The file event type.
-  ---@enum lsp.FileChangeType
   FileChangeType = {
     -- The file got created.
     Created = 1,
@@ -846,10 +841,6 @@ function protocol.make_client_capabilities()
       semanticTokens = {
         refreshSupport = true,
       },
-      didChangeWatchedFiles = {
-        dynamicRegistration = true,
-        relativePatternSupport = true,
-      },
     },
     experimental = nil,
     window = {