fix: session diff keymaps

README.md

@@ -1191,6 +1191,29 @@ Press `r` to select a range of turns/messages: move through user prompts, mark t
 
 Press `q` to close the review tab. `:Opencode diff next` and `:Opencode diff prev` also select files in the open review tab.
 
+Press `gf` in the file list or diff preview to open the selected working-tree file in a new tab, keeping the snapshot review intact. From a preview, it targets the corresponding post-change line (deleted lines use the next surviving line, or the last one), clamped to the current file's length. This is best-effort if the working tree has changed since the snapshot. Diff panes show absolute line numbers. If the file no longer exists on disk, a warning is shown instead. Remap this using the `open_file` action.
+
+### Customize session-diff keymaps
+
+Like panel mappings, `keymap.session_diff` binds keys to `{ action, { arguments }, mode = ..., desc = ..., nowait = ... }` entries, using the same keymap utility. Actions can be local diff action names, panel command names, or Lua callbacks; local diff actions take precedence. Set a default key to `false` to disable it. `<Tab>` / `<S-Tab>` select the next / previous file in the list and diff panes.
+
+```lua
+keymap = {
+  session_diff = {
+    preview = {
+      [']f'] = { 'next_file', desc = 'Next file' },
+      ['[f'] = { 'prev_file', desc = 'Previous file' },
+      ['<M-e>'] = { function() vim.cmd('wincmd h') end, desc = 'Focus file list' },
+    },
+    list = {
+      ['<M-e>'] = { function() vim.cmd('wincmd l') end, desc = 'Focus diff' },
+    },
+  },
+}
+```
+
+Dedicated filetypes are `opencode_diff_list`, `opencode_diff_messages`, `opencode_diff_help`, and `opencode_diff_comment`. Preview buffers use composite filetypes such as `lua.opencode_diff_preview`, `diff.opencode_diff_preview`, and `markdown.opencode_diff_message_preview`, keeping source syntax highlighting. Use `FileType` patterns `*.opencode_diff_preview` or `*.opencode_diff_message_preview` to attach your own buffer-local mappings; configured mappings are installed before these hooks run.
+
 ### Comment on a session diff
 
 In a diff preview, press `c` on a line or visual selection to add or edit a review comment. Use `dc` to remove one; `]r` and `[r` move between comments. In the comment editor, `<C-s>` or `:w` saves, while `q` or `<Esc>` cancels. Comments appear as signs and in the file tree; closing the review focuses the input when comments are pending. Comments are sent with the next prompt and include the reviewed snapshot and a best-effort current-file status.

lua/opencode/config.lua

@@ -33,6 +33,9 @@ M.defaults = {
     session_diff = {
       list = {
         ['<CR>'] = { 'activate', desc = 'Open file or toggle folder' },
+        ['gf'] = { 'open_file', desc = 'Open working-tree file in a new tab' },
+        ['<Tab>'] = { 'next_file', desc = 'Next file' },
+        ['<S-Tab>'] = { 'prev_file', desc = 'Previous file' },
         ['r'] = { 'toggle_range', desc = 'Choose message range', nowait = true },
         ['p'] = { 'toggle_view', desc = 'Toggle diff layout' },
         ['q'] = { 'close', desc = 'Close diff', nowait = true },
@@ -49,6 +52,9 @@ M.defaults = {
         ['g?'] = { 'toggle_help', desc = 'Toggle keymap help' },
       },
       preview = {
+        ['gf'] = { 'open_file', desc = 'Open working-tree file in a new tab' },
+        ['<Tab>'] = { 'next_file', desc = 'Next file' },
+        ['<S-Tab>'] = { 'prev_file', desc = 'Previous file' },
         ['q'] = { 'close', desc = 'Close diff', nowait = true },
         ['p'] = { 'toggle_view', desc = 'Toggle diff layout' },
         ['g?'] = { 'toggle_help', desc = 'Toggle keymap help' },

lua/opencode/keymap.lua

@@ -1,5 +1,4 @@
 local M = {}
-local commands = require('opencode.commands')
 local store = require('opencode.state.store')
 local window_keymaps = {}
 
@@ -24,13 +23,21 @@ end
 
 ---@param func_name string|function
 ---@param func_args any
+---@param actions? table<string, function?> Buffer-local overrides take precedence over panel commands
 ---@return function|nil
-local function resolve_callback(func_name, func_args)
+local function resolve_callback(func_name, func_args, actions)
+  if type(func_name) == 'string' and actions and actions[func_name] then
+    func_name = actions[func_name]
+  end
   if type(func_name) == 'function' then
-    return func_name
+    return function()
+      local args = func_args and (type(func_args) == 'table' and vim.deepcopy(func_args) or { func_args }) or {}
+      return func_name(unpack(args))
+    end
   end
 
   if type(func_name) == 'string' then
+    local commands = require('opencode.commands')
     local command_defs = commands.get_commands()
     if command_defs[func_name] then
       return function()
@@ -51,7 +58,10 @@ end
 ---@param default_modes table Default modes for these keymaps
 ---@param base_opts table Base options to use for all keymaps
 ---@param preserve_existing? boolean
-local function process_keymap_entry(keymap_config, default_modes, base_opts, preserve_existing)
+---@param actions? table<string, function?>
+local function process_keymap_entry(keymap_config, default_modes, base_opts, preserve_existing, actions)
+  -- Commands load diff handlers, which also use this mapper for their buffers.
+  local commands = require('opencode.commands')
   local command_defs = commands.get_commands()
 
   for key_binding, config_entry in pairs(keymap_config) do
@@ -60,7 +70,7 @@ local function process_keymap_entry(keymap_config, default_modes, base_opts, pre
     elseif config_entry then
       local func_name = config_entry[1]
       local func_args = config_entry[2]
-      local callback = resolve_callback(func_name, func_args)
+      local callback = resolve_callback(func_name, func_args, actions)
 
       local modes = config_entry.mode or default_modes
       if preserve_existing and base_opts.buffer then
@@ -81,7 +91,10 @@ local function process_keymap_entry(keymap_config, default_modes, base_opts, pre
       end
       local opts = vim.tbl_deep_extend('force', {}, base_opts)
       opts.nowait = config_entry.nowait
-      opts.desc = config_entry.desc or vim.tbl_get(command_defs, func_name, 'desc') or ''
+      local command_desc = type(func_name) == 'string'
+        and not (actions and actions[func_name])
+        and vim.tbl_get(command_defs, func_name, 'desc')
+      opts.desc = config_entry.desc or command_desc or ''
 
       if not callback then
         if type(func_name) ~= 'string' then
@@ -131,12 +144,13 @@ end
 ---@param keymap_config table Window keymap configuration
 ---@param buf_id integer Buffer ID to set keymaps for
 ---@param preserve_existing? boolean
-function M.setup_window_keymaps(keymap_config, buf_id, preserve_existing)
+---@param actions? table<string, function?> Local action overrides; unknown names use command resolution and its error notification
+function M.setup_window_keymaps(keymap_config, buf_id, preserve_existing, actions)
   if not vim.api.nvim_buf_is_valid(buf_id) then
     return
   end
 
-  process_keymap_entry(keymap_config or {}, { 'n' }, { silent = true, buffer = buf_id }, preserve_existing)
+  process_keymap_entry(keymap_config or {}, { 'n' }, { silent = true, buffer = buf_id }, preserve_existing, actions)
 end
 
 return M

lua/opencode/types.lua

@@ -159,7 +159,8 @@
 ---@field project SessionProjectInfo|nil
 
 ---@class OpencodeKeymapEntry
----@field [1] string # Function name
+---@field [1] string|function # Action name or callback
+---@field [2]? any # Arguments passed to the action or callback
 ---@field mode? string|string[] # Mode(s) for the keymap
 ---@field desc? string # Keymap description
 ---@field nowait? boolean # Execute without waiting for longer mappings
@@ -169,11 +170,21 @@
 ---@class OpencodeKeymapInputWindow : table<string, OpencodeKeymapEntry>
 ---@class OpencodeKeymapOutputWindow : table<string, OpencodeKeymapEntry>
 
+---@alias OpencodeSessionDiffMappings table<string, OpencodeKeymapEntry|false>
+
+---@class OpencodeSessionDiffKeymaps
+---@field list OpencodeSessionDiffMappings
+---@field messages OpencodeSessionDiffMappings
+---@field preview OpencodeSessionDiffMappings
+---@field comment OpencodeSessionDiffMappings
+---@field message_preview OpencodeSessionDiffMappings
+---@field help OpencodeSessionDiffMappings
+
 ---@class OpencodeKeymap
 ---@field editor OpencodeKeymapEditor
 ---@field input_window OpencodeKeymapInputWindow
 ---@field output_window OpencodeKeymapOutputWindow
----@field session_diff {list: table<string, OpencodeKeymapEntry|false>, messages: table<string, OpencodeKeymapEntry|false>, preview: table<string, OpencodeKeymapEntry|false>, comment: table<string, OpencodeKeymapEntry|false>, message_preview: table<string, OpencodeKeymapEntry|false>, help: table<string, OpencodeKeymapEntry|false>}
+---@field session_diff OpencodeSessionDiffKeymaps
 ---@field tab_strip_window table<string, OpencodeKeymapEntry>
 ---@field session_picker OpencodeSessionPickerKeymap
 ---@field session_tab_picker OpencodeSessionTabPickerKeymap

lua/opencode/ui/session_diff.lua

@@ -2,6 +2,7 @@ local patch = require('opencode.session_patch')
 local config = require('opencode.config')
 local float_layout = require('opencode.ui.float_layout')
 local help = require('opencode.ui.session_diff.help')
+local keymaps = require('opencode.keymap')
 local icons = require('opencode.ui.icons')
 local render = require('opencode.ui.session_diff.render')
 local context = require('opencode.context')
@@ -112,17 +113,16 @@ local function map_actions(buf, scope)
     prev_comment = function()
       M.jump_comment(-1)
     end,
+    next_file = function()
+      M.select(1)
+    end,
+    prev_file = function()
+      M.select(-1)
+    end,
+    select = M.select,
+    open_file = M.open_file,
   }
-  for key, entry in pairs(config.keymap.session_diff[scope]) do
-    if entry ~= false then
-      vim.keymap.set(entry.mode or 'n', key, actions[entry[1]], {
-        buffer = buf,
-        silent = true,
-        desc = entry.desc,
-        nowait = entry.nowait,
-      })
-    end
-  end
+  keymaps.setup_window_keymaps(config.keymap.session_diff[scope], buf, false, actions)
 end
 
 local function help_key()
@@ -216,6 +216,7 @@ function M.toggle_help()
 
   local buf, width, height = help.create(config.keymap.session_diff)
   map_actions(buf, 'help')
+  vim.bo[buf].filetype = 'opencode_diff_help'
   view.help_return_win = vim.api.nvim_get_current_win()
   view.help_win = vim.api.nvim_open_win(buf, true, {
     relative = 'editor',
@@ -234,7 +235,6 @@ end
 local function open_turn_window()
   local buf = vim.api.nvim_create_buf(false, true)
   vim.bo[buf].bufhidden = 'wipe'
-  vim.bo[buf].filetype = ''
   vim.bo[buf].modifiable = false
   local win_config = float_layout.window_configs(nil, false)
   win_config.width = math.min(assert(win_config.width), math.floor(vim.o.columns * 0.75)) --[[@as integer]]
@@ -251,6 +251,7 @@ local function open_turn_window()
   vim.wo[view.turn_win].relativenumber = false
   vim.wo[view.turn_win].signcolumn = 'no'
   map_actions(buf, 'messages')
+  vim.bo[buf].filetype = 'opencode_diff_messages'
 end
 
 local function close_turn_window()
@@ -388,16 +389,24 @@ scratch = function(lines, filetype, scope)
   local buf = vim.api.nvim_create_buf(false, true)
   vim.bo[buf].bufhidden = 'wipe'
   vim.api.nvim_buf_set_lines(buf, 0, -1, false, lines)
-  vim.bo[buf].filetype = filetype
   vim.bo[buf].modifiable = false
   map_actions(buf, scope or 'preview')
+  if scope == 'list' then
+    vim.bo[buf].filetype = 'opencode_diff_list'
+  else
+    local suffix = scope == 'message_preview' and 'opencode_diff_message_preview' or 'opencode_diff_preview'
+    vim.bo[buf].filetype = filetype ~= '' and (filetype .. '.' .. suffix) or suffix
+    vim.bo[buf].syntax = filetype
+  end
   return buf
 end
 
 local function set_preview(win, lines, filetype)
   vim.api.nvim_win_set_buf(win, scratch(lines, filetype))
   vim.api.nvim_win_set_cursor(win, { 1, 0 })
   vim.wo[win].signcolumn = 'yes:1'
+  vim.wo[win].number = true
+  vim.wo[win].relativenumber = false
 end
 
 local function refresh_comments()
@@ -732,6 +741,63 @@ function M.activate()
   vim.api.nvim_win_set_cursor(view.list_win, { row, 0 })
 end
 
+---@param win integer
+---@return integer
+local function working_tree_line(win)
+  local row = vim.api.nvim_win_get_cursor(win)[1]
+  if view.sides[win] == 'after' then
+    return row
+  end
+  if view.sides[win] == 'before' then
+    for index, entry in ipairs(view.patch_map) do
+      if entry.old == row then
+        row = index
+        break
+      end
+    end
+  end
+  -- Deleted lines and patch headers target the next surviving line, or the last one.
+  for index = row, #view.patch_map do
+    local number = view.patch_map[index].new
+    if number then
+      return number
+    end
+  end
+  for index = math.min(row - 1, #view.patch_map), 1, -1 do
+    local number = view.patch_map[index].new
+    if number then
+      return number
+    end
+  end
+  return 1
+end
+
+function M.open_file()
+  if not in_view() or #view.files == 0 then
+    return
+  end
+  local index = view.index
+  local win = vim.api.nvim_get_current_win()
+  local line = 1
+  if win == view.list_win then
+    local node = view.rows[vim.api.nvim_win_get_cursor(view.list_win)[1]]
+    if not node or not node.file_index then
+      return
+    end
+    index = node.file_index
+  elseif win == view.preview_win or win == view.right_win then
+    line = working_tree_line(win)
+  end
+  local file = view.files[index]
+  if vim.fn.filereadable(file.file) == 0 then
+    vim.notify('Working-tree file not found: ' .. file.file, vim.log.levels.WARN)
+    return
+  end
+  -- Keep snapshot previews intact while editing the current working-tree revision.
+  vim.cmd('tabedit ' .. vim.fn.fnameescape(file.file))
+  vim.api.nvim_win_set_cursor(0, { math.min(line, vim.api.nvim_buf_line_count(0)), 0 })
+end
+
 function M.select(direction)
   if not active() then
     return false
@@ -856,6 +922,7 @@ function M.open(files, session, options)
   vim.wo[list_win].relativenumber = false
   vim.wo[list_win].signcolumn = 'no'
   vim.wo[list_win].cursorline = true
+  vim.wo[list_win].wrap = false
   vim.cmd('rightbelow vsplit')
   local preview_win = vim.api.nvim_get_current_win()
   vim.api.nvim_set_current_win(list_win)

lua/opencode/ui/session_diff/comment_input.lua

@@ -1,4 +1,5 @@
 local config = require('opencode.config')
+local keymaps = require('opencode.keymap')
 
 local M = {}
 
@@ -71,16 +72,8 @@ function M.open(opts)
   end
   vim.api.nvim_create_autocmd('BufWriteCmd', { buffer = buf, callback = submit })
   local actions = { submit_comment = submit, cancel_comment = cancel }
-  for key, entry in pairs(config.keymap.session_diff.comment) do
-    if entry ~= false then
-      vim.keymap.set(entry.mode or 'n', key, actions[entry[1]], {
-        buffer = buf,
-        silent = true,
-        desc = entry.desc,
-        nowait = entry.nowait,
-      })
-    end
-  end
+  keymaps.setup_window_keymaps(config.keymap.session_diff.comment, buf, false, actions)
+  vim.bo[buf].filetype = 'opencode_diff_comment'
   vim.cmd('startinsert')
 end
 

lua/opencode/ui/session_diff/help.lua

@@ -17,6 +17,10 @@ local action_order = {
   prev_comment = 13,
   submit_comment = 14,
   cancel_comment = 15,
+  next_file = 16,
+  prev_file = 17,
+  select = 18,
+  open_file = 19,
 }
 
 ---@class OpencodeSessionDiffHelpSection
@@ -25,13 +29,14 @@ local action_order = {
 ---@field width integer
 
 ---@param title string
----@param mappings table<string, OpencodeKeymapEntry|false>
+---@param mappings OpencodeSessionDiffMappings
 ---@return OpencodeSessionDiffHelpSection
 local function section(title, mappings)
   local entries = {}
   for key, entry in pairs(mappings) do
     if entry ~= false then
-      entries[#entries + 1] = { key = key, action = entry[1], label = entry.desc or entry[1] }
+      local action = type(entry[1]) == 'string' and entry[1] or 'Custom callback'
+      entries[#entries + 1] = { key = key, action = action, label = entry.desc or action }
     end
   end
   table.sort(entries, function(a, b)
@@ -45,7 +50,7 @@ local function section(title, mappings)
   return { title = title, entries = entries, width = width }
 end
 
----@param keymaps {list: table<string, OpencodeKeymapEntry|false>, messages: table<string, OpencodeKeymapEntry|false>, preview: table<string, OpencodeKeymapEntry|false>, comment: table<string, OpencodeKeymapEntry|false>, message_preview: table<string, OpencodeKeymapEntry|false>, help: table<string, OpencodeKeymapEntry|false>}
+---@param keymaps OpencodeSessionDiffKeymaps
 ---@return integer, integer, integer
 function M.create(keymaps)
   local sections = {