fix: track note positions with extmarks to survive file edits

.luarc.json

@@ -4,6 +4,17 @@
     "version": "LuaJIT"
   },
   "workspace": {
-    "library": ["lua", "$VIMRUNTIME", "${3rd}/luv/library"]
+    "library": [
+      "lua",
+      "$VIMRUNTIME",
+      "${3rd}/luv/library",
+      "${3rd}/busted/library",
+      "${3rd}/luassert/library"
+    ]
+  },
+  "diagnostics": {
+    "globals": [
+      "vim",
+    ]
   }
 }

lua/tabi/extmarks.lua

@@ -0,0 +1,80 @@
+---@class TabiExtmarks
+local M = {}
+
+-- Namespace for position-tracking extmarks (separate from the display namespace)
+local ns = vim.api.nvim_create_namespace("tabi_positions")
+
+-- Per-buffer mapping: bufnr -> { [note_id] -> { start_id: number, end_id: number } }
+local _buf_marks = {}
+
+--- Register extmarks for a note so its position is tracked across edits
+---@param bufnr number
+---@param note NoteData
+function M.track(bufnr, note)
+  if not vim.api.nvim_buf_is_valid(bufnr) then
+    return
+  end
+
+  if not _buf_marks[bufnr] then
+    _buf_marks[bufnr] = {}
+  end
+
+  -- Remove stale extmarks for this note before re-creating
+  M.untrack(bufnr, note.id)
+
+  local line_count = vim.api.nvim_buf_line_count(bufnr)
+  local start_row = math.min(note.line - 1, line_count - 1)
+  local end_row = math.min((note.end_line or note.line) - 1, line_count - 1)
+
+  local start_id = vim.api.nvim_buf_set_extmark(bufnr, ns, start_row, 0, {})
+  local end_id = vim.api.nvim_buf_set_extmark(bufnr, ns, end_row, 0, {})
+
+  _buf_marks[bufnr][note.id] = { start_id = start_id, end_id = end_id }
+end
+
+--- Remove extmarks for a specific note
+---@param bufnr number
+---@param note_id string
+function M.untrack(bufnr, note_id)
+  if not _buf_marks[bufnr] or not _buf_marks[bufnr][note_id] then
+    return
+  end
+  local ids = _buf_marks[bufnr][note_id]
+  pcall(vim.api.nvim_buf_del_extmark, bufnr, ns, ids.start_id)
+  pcall(vim.api.nvim_buf_del_extmark, bufnr, ns, ids.end_id)
+  _buf_marks[bufnr][note_id] = nil
+end
+
+--- Get current positions (1-indexed) for all tracked notes in a buffer
+---@param bufnr number
+---@return table<string, {line: number, end_line: number}>
+function M.get_positions(bufnr)
+  if not _buf_marks[bufnr] then
+    return {}
+  end
+
+  local positions = {}
+  for note_id, ids in pairs(_buf_marks[bufnr]) do
+    local start_pos = vim.api.nvim_buf_get_extmark_by_id(bufnr, ns, ids.start_id, {})
+    local end_pos = vim.api.nvim_buf_get_extmark_by_id(bufnr, ns, ids.end_id, {})
+
+    if start_pos and #start_pos >= 1 and end_pos and #end_pos >= 1 then
+      positions[note_id] = {
+        line = start_pos[1] + 1, -- convert 0-indexed row to 1-indexed line
+        end_line = end_pos[1] + 1,
+      }
+    end
+  end
+  return positions
+end
+
+--- Clear all extmarks for a buffer and remove it from the tracking table
+---@param bufnr number
+function M.clear(bufnr)
+  if vim.api.nvim_buf_is_valid(bufnr) then
+    vim.api.nvim_buf_clear_namespace(bufnr, ns, 0, -1)
+  end
+  _buf_marks[bufnr] = nil
+end
+
+return M

lua/tabi/init.lua

@@ -76,7 +76,8 @@ function M._setup_default_session_display()
     callback = function(args)
       -- Only show when no named session or retrace is active
       if not M.state.current_session and not require("tabi.retrace").is_active() then
-        display.update_for_session(args.buf, default_session)
+        local fresh = session_module.load("default")
+        display.update_for_session(args.buf, fresh or default_session)
       end
     end,
   })

lua/tabi/session.lua

@@ -170,6 +170,10 @@ end
 function M.remove_note(session, note_id)
   for i, note in ipairs(session.notes) do
     if note.id == note_id then
+      local bufnr = vim.fn.bufnr(note.file)
+      if bufnr ~= -1 then
+        require("tabi.extmarks").untrack(bufnr, note_id)
+      end
       table.remove(session.notes, i)
       return M.save(session)
     end
@@ -206,6 +210,44 @@ function M.get_notes_for_file(session, file_path)
   return notes
 end
 
+--- Sync note positions from extmarks for notes belonging to a specific buffer.
+--- Should be called before saving so that line numbers reflect the current state
+--- of the buffer after edits.
+---@param session SessionData
+---@param bufnr number
+---@return boolean changed Whether any positions were updated
+function M.sync_positions_from_extmarks(session, bufnr)
+  if not vim.api.nvim_buf_is_valid(bufnr) then
+    return false
+  end
+
+  local file_path = vim.api.nvim_buf_get_name(bufnr)
+  if file_path == "" then
+    return false
+  end
+
+  local extmarks = require("tabi.extmarks")
+  local positions = extmarks.get_positions(bufnr)
+  local changed = false
+
+  for _, note in ipairs(session.notes) do
+    if note.file == file_path and positions[note.id] then
+      local pos = positions[note.id]
+      if note.line ~= pos.line or note.end_line ~= pos.end_line then
+        note.line = pos.line
+        note.end_line = pos.end_line
+        changed = true
+      end
+    end
+  end
+
+  if changed then
+    M.save(session)
+  end
+
+  return changed
+end
+
 --- Get note at specific line
 ---@param session SessionData
 ---@param file_path string

lua/tabi/ui/display.lua

@@ -92,8 +92,22 @@ end
 function M.refresh_buffer(bufnr, notes)
   M.clear_buffer(bufnr)
 
+  local extmarks = require("tabi.extmarks")
+
+  -- Capture positions tracked by extmarks BEFORE clearing them.
+  -- These reflect any line shifts caused by edits since the last save,
+  -- so they must take priority over the (possibly stale) positions in the session file.
+  local tracked_positions = extmarks.get_positions(bufnr)
+  extmarks.clear(bufnr)
+
   for _, note in ipairs(notes) do
+    local pos = tracked_positions[note.id]
+    if pos then
+      note.line = pos.line
+      note.end_line = pos.end_line
+    end
     M.display_note_as_virtual_line(bufnr, note)
+    extmarks.track(bufnr, note)
   end
 end
 
@@ -125,7 +139,8 @@ function M.setup_autocmds(session)
   vim.api.nvim_create_autocmd({ "BufEnter", "BufWinEnter" }, {
     group = group,
     callback = function(args)
-      M.update_for_session(args.buf, session)
+      local fresh = require("tabi.session").load(session.id)
+      M.update_for_session(args.buf, fresh or session)
     end,
   })
 
@@ -137,6 +152,14 @@ function M.setup_autocmds(session)
       -- M.clear_buffer(args.buf)
     end,
   })
+
+  -- Clean up extmarks when a buffer is deleted
+  vim.api.nvim_create_autocmd("BufDelete", {
+    group = group,
+    callback = function(args)
+      require("tabi.extmarks").clear(args.buf)
+    end,
+  })
 end
 
 --- Clear all autocommands

plugin/tabi.lua

@@ -368,6 +368,27 @@ function commands.session_rename(args)
   end
 end
 
+-- Sync note positions from extmarks just before the buffer is written to disk
+vim.api.nvim_create_autocmd("BufWritePre", {
+  group = vim.api.nvim_create_augroup("TabiPositionSync", { clear = true }),
+  callback = function(args)
+    -- Prefer the explicitly active session; fall back to the default session
+    -- when show_default_notes is displaying notes without an active session
+    -- (e.g. after a Neovim restart).
+    local session_id = tabi.state.current_session
+    if not session_id then
+      if not require("tabi.config").get().show_default_notes then
+        return
+      end
+      session_id = "default"
+    end
+    local session = session_module.load(session_id)
+    if session then
+      session_module.sync_positions_from_extmarks(session, args.buf)
+    end
+  end,
+})
+
 -- Create user commands
 vim.api.nvim_create_user_command("Tabi", function(opts)
   local args = vim.split(vim.trim(opts.args), "%s+")