feat: improve how buffers are watched (#2897)

Author: olimorris

lua/codecompanion/config.lua

@@ -57,6 +57,12 @@ local defaults = {
   },
   constants = constants,
   interactions = {
+    opts = {
+      watcher = {
+        enabled = true, -- Reload buffers when an agent modifies files on disk
+        debounce = 500, -- Debounce time in milliseconds
+      },
+    },
     -- BACKGROUND INTERACTION -------------------------------------------------
     background = {
       adapter = {
@@ -753,7 +759,6 @@ The user is working on a %s machine. Please respond with system specific command
       agents = {},
       opts = {
         auto_insert = false, -- Enter insert mode when focusing the CLI terminal
-        reload = true, -- Reload buffers when an agent modifies files on disk
       },
       providers = {
         terminal = {

lua/codecompanion/interactions/chat/acp/handler.lua

@@ -2,6 +2,7 @@ local config = require("codecompanion.config")
 local formatter = require("codecompanion.interactions.chat.acp.formatters")
 local log = require("codecompanion.utils.log")
 local utils = require("codecompanion.utils")
+local watch = require("codecompanion.interactions.shared.watch")
 
 -- Keep a record of UI changes in the chat buffer
 
@@ -19,7 +20,6 @@ local ACPHandlerUI = {} -- Cache of tool call UI states by chat buffer
 function ACPHandler.new(chat)
   local self = setmetatable({
     chat = chat,
-    modified_paths = {},
     output = {},
     reasoning = {},
     tools = {},
@@ -83,6 +83,8 @@ function ACPHandler:ensure_connection()
     end
 
     self.chat:update_metadata()
+
+    watch.enable()
   end
   return true
 end
@@ -209,24 +211,6 @@ function ACPHandler:process_tool_call(tool_call)
     content = "[Error formatting tool output]"
   end
 
-  -- Track file paths from edit/write tool calls for targeted buffer reload
-  if tool_call.kind == "edit" then
-    if type(tool_call.locations) == "table" then
-      for _, loc in ipairs(tool_call.locations) do
-        if type(loc.path) == "string" then
-          self.modified_paths[loc.path] = true
-        end
-      end
-    end
-    if type(tool_call.content) == "table" then
-      for _, c in ipairs(tool_call.content) do
-        if c.type == "diff" and type(c.path) == "string" then
-          self.modified_paths[c.path] = true
-        end
-      end
-    end
-  end
-
   -- Cache or cleanup
   if tool_call.status == "completed" then
     self.tools[id] = nil
@@ -324,21 +308,6 @@ function ACPHandler:handle_completion(stop_reason)
     self.chat.status = "success"
   end
 
-  -- Reload buffers that the agent modified on disk
-  if next(self.modified_paths) then
-    local modified = self.modified_paths
-    self.modified_paths = {}
-    vim.schedule(function()
-      local buf_utils = require("codecompanion.utils.buffers")
-      for path, _ in pairs(modified) do
-        local bufnr = buf_utils.get_bufnr_from_path(path)
-        if bufnr then
-          vim.cmd.checktime(bufnr)
-        end
-      end
-    end)
-  end
-
   self.chat:done(self.output, self.reasoning, {})
 end
 

lua/codecompanion/interactions/cli/init.lua

@@ -1,16 +1,12 @@
--- File watching logic inspired and adapted from sidekick.nvim
--- https://github.com/folke/sidekick.nvim
-
 local config = require("codecompanion.config")
 local keymaps = require("codecompanion.utils.keymaps")
 local log = require("codecompanion.utils.log")
 local registry = require("codecompanion.interactions.shared.registry")
 local utils = require("codecompanion.utils")
+local watch = require("codecompanion.interactions.shared.watch")
 
 local api = vim.api
 
-local uv = vim.uv or vim.loop
-
 ---@type table
 _G.codecompanion_cli_metadata = {}
 
@@ -22,20 +18,11 @@ _G.codecompanion_cli_metadata = {}
 ---@field id number
 ---@field provider CodeCompanion.CLI.Provider
 ---@field ui CodeCompanion.CLI.UI
----@field watch_cwd string|nil
 local CLI = {}
 
 local clis = {} ---@type table<number, CodeCompanion.CLI>
 local last_cli = nil ---@type CodeCompanion.CLI|nil
 
----@class CodeCompanion.CLI.Watcher
----@field watcher uv.uv_fs_event_t
----@field timer uv.uv_timer_t
----@field count number
-
----Shared watchers keyed by cwd — one watcher per directory, ref-counted
-local watchers = {} ---@type table<string, CodeCompanion.CLI.Watcher>
-
 ---Keymap callbacks for the CLI buffer
 local keymap_callbacks = {
   next_chat = {
@@ -128,10 +115,7 @@ function CLI.create(args)
     })
   end
 
-  if config.interactions.cli.opts.reload then
-    self.watch_cwd = vim.fn.getcwd()
-    self._start_watcher(self.watch_cwd)
-  end
+  watch.enable()
 
   clis[bufnr] = self
   last_cli = self
@@ -251,9 +235,6 @@ end
 ---Close the CLI instance and clean up
 ---@return nil
 function CLI:close()
-  if self.watch_cwd then
-    self._stop_watcher(self.watch_cwd)
-  end
   self.provider:stop()
 
   pcall(api.nvim_del_augroup_by_id, self.aug)
@@ -274,70 +255,6 @@ function CLI:close()
   utils.fire("CLIClosed", { bufnr = self.bufnr })
 end
 
---=============================================================================
--- Watchers - Monitor files in the cwd for any changes
---=============================================================================
-
----Start a watcher for a given cwd
----@param cwd string
----@return nil
-function CLI._start_watcher(cwd)
-  if watchers[cwd] then
-    watchers[cwd].count = watchers[cwd].count + 1
-    return
-  end
-
-  local watcher = uv.new_fs_event()
-  if not watcher then
-    return log:warn("Could not create file watcher for %s", cwd)
-  end
-
-  local timer = uv.new_timer()
-  if not timer then
-    watcher:close()
-    return log:warn("Could not create debounce timer for %s", cwd)
-  end
-
-  watcher:start(cwd, { recursive = true }, function()
-    if not timer:is_closing() then
-      timer:stop()
-      timer:start(100, 0, function()
-        vim.schedule(vim.cmd.checktime)
-      end)
-    end
-  end)
-
-  watchers[cwd] = { watcher = watcher, timer = timer, count = 1 }
-  log:debug("File watcher started on %s", cwd)
-end
-
----Stop a watcher for the given cwd
----@param cwd string
----@return nil
-function CLI._stop_watcher(cwd)
-  local entry = watchers[cwd]
-  if not entry then
-    return
-  end
-
-  entry.count = entry.count - 1
-  if entry.count > 0 then
-    return
-  end
-
-  if not entry.timer:is_closing() then
-    entry.timer:stop()
-    entry.timer:close()
-  end
-  if not entry.watcher:is_closing() then
-    entry.watcher:stop()
-    entry.watcher:close()
-  end
-
-  watchers[cwd] = nil
-  log:debug("File watcher stopped for %s", cwd)
-end
-
 --=============================================================================
 -- Public API
 -- =============================================================================

lua/codecompanion/interactions/shared/watch.lua

@@ -0,0 +1,154 @@
+-- File watching logic inspired and adapted from sidekick.nvim
+-- https://github.com/folke/sidekick.nvim/blob/main/lua/sidekick/cli/watch.lua
+
+local config = require("codecompanion.config")
+local log = require("codecompanion.utils.log")
+
+local api = vim.api
+local uv = vim.uv or vim.loop
+
+local M = {}
+
+M.watches = {} ---@type table<string, uv.uv_fs_event_t>
+M.enabled = false
+
+---Debounce a function using a libuv timer
+---@generic T
+---@param fn T
+---@param ms? number
+---@return T
+local function debounce(fn, ms)
+  local timer = assert(uv.new_timer())
+  return function(...)
+    local args = { ... }
+    timer:start(
+      ms or 20,
+      0,
+      vim.schedule_wrap(function()
+        pcall(fn, unpack(args))
+      end)
+    )
+  end
+end
+
+---Return the parent directory of a buffer's file, or nil if ineligible
+---@param buf number
+---@return string|nil
+local function dirname(buf)
+  local fname = api.nvim_buf_get_name(buf)
+  if
+    api.nvim_buf_is_loaded(buf)
+    and vim.bo[buf].buftype == ""
+    and vim.bo[buf].buflisted
+    and fname ~= ""
+    and uv.fs_stat(fname) ~= nil
+  then
+    local path = vim.fs.dirname(fname)
+    return path and path ~= "" and path or nil
+  end
+end
+
+---Refresh checktime
+---@return nil
+function M.refresh()
+  vim.cmd.checktime()
+end
+
+---Start watching a specific directory path
+---@param path string
+---@return nil
+function M.start(path)
+  if M.watches[path] then
+    return
+  end
+
+  local watch = uv.new_fs_event()
+  if not watch then
+    return log:warn("Could not create file watcher for %s", path)
+  end
+
+  local ok, err = watch:start(path, {}, function()
+    M.refresh()
+  end)
+  if not ok then
+    log:warn("Failed to watch %s: %s", path, err)
+    if not watch:is_closing() then
+      watch:close()
+    end
+    return
+  end
+
+  M.watches[path] = watch
+  log:debug("File watcher started on %s", path)
+end
+
+---Stop watching a specific directory path
+---@param path string
+---@return nil
+function M.stop(path)
+  local watch = M.watches[path]
+  if not watch then
+    return
+  end
+
+  M.watches[path] = nil
+  if not watch:is_closing() then
+    watch:close()
+  end
+  log:debug("File watcher stopped for %s", path)
+end
+
+---Update watches based on currently loaded buffers.
+---Starts watches for new buffer directories and stops watches for removed ones.
+---@return nil
+function M.update()
+  local dirs = {} ---@type table<string, boolean>
+  for _, buf in pairs(api.nvim_list_bufs()) do
+    local dir = dirname(buf)
+    if dir then
+      dirs[dir] = true
+      M.start(dir)
+    end
+  end
+  for path in pairs(M.watches) do
+    if not dirs[path] then
+      M.stop(path)
+    end
+  end
+end
+
+---Enable file system watching for all loaded buffers
+---@return nil
+function M.enable()
+  local watcher = config.interactions.opts.watcher
+  if M.enabled or not watcher.enabled then
+    return
+  end
+
+  M.enabled = true
+  M.refresh = debounce(M.refresh, watcher.debounce)
+  M.update = debounce(M.update, watcher.debounce)
+
+  api.nvim_create_autocmd({ "BufAdd", "BufDelete", "BufWipeout", "BufReadPost" }, {
+    group = api.nvim_create_augroup("codecompanion.watch", { clear = true }),
+    callback = M.update,
+  })
+  M.update()
+end
+
+---Disable file system watching and stop all active watches
+---@return nil
+function M.disable()
+  if not M.enabled then
+    return
+  end
+
+  M.enabled = false
+  pcall(api.nvim_clear_autocmds, { group = "codecompanion.watch" })
+  pcall(api.nvim_del_augroup_by_name, "codecompanion.watch")
+  for path in pairs(M.watches) do
+    M.stop(path)
+  end
+end
+
+return M

tests/config.lua

@@ -74,6 +74,12 @@ return {
     },
   },
   interactions = {
+    opts = {
+      watcher = {
+        enabled = true,
+        debounce = 500,
+      },
+    },
     background = {},
     chat = {
       adapter = "test_adapter",