From b734e57d0f5e730679249095c44e6a6508bd175e Mon Sep 17 00:00:00 2001
From: Francis Belanger <francis.belanger@gmail.com>
Date: Wed, 7 Oct 2026 08:26:02 -0400
Subject: [PATCH 1/4] feat: reuse panel keymap utility for session diffs

---
 README.md                                     | 21 +++++++
 lua/opencode/config.lua                       |  4 ++
 lua/opencode/keymap.lua                       | 30 +++++++---
 lua/opencode/types.lua                        | 15 ++++-
 lua/opencode/ui/session_diff.lua              | 30 ++++++----
 .../ui/session_diff/comment_input.lua         | 13 +----
 lua/opencode/ui/session_diff/help.lua         | 10 +++-
 tests/unit/keymap_spec.lua                    | 40 ++++++++++++++
 .../unit/session_diff_comment_input_spec.lua  | 25 +++++++--
 tests/unit/session_diff_spec.lua              | 55 +++++++++++++++++++
 10 files changed, 204 insertions(+), 39 deletions(-)

diff --git a/README.md b/README.md
index ff2936d2..b7c6be82 100644
--- a/README.md
+++ b/README.md
@@ -1191,6 +1191,27 @@ 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.
 
+### 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.
diff --git a/lua/opencode/config.lua b/lua/opencode/config.lua
index a52500d2..60679cb4 100644
--- a/lua/opencode/config.lua
+++ b/lua/opencode/config.lua
@@ -33,6 +33,8 @@ M.defaults = {
     session_diff = {
       list = {
         ['<CR>'] = { 'activate', desc = 'Open file or toggle folder' },
+        ['<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 +51,8 @@ M.defaults = {
         ['g?'] = { 'toggle_help', desc = 'Toggle keymap help' },
       },
       preview = {
+        ['<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' },
diff --git a/lua/opencode/keymap.lua b/lua/opencode/keymap.lua
index a705031f..8e1e0f71 100644
--- a/lua/opencode/keymap.lua
+++ b/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
diff --git a/lua/opencode/types.lua b/lua/opencode/types.lua
index fdacc27e..a06e6016 100644
--- a/lua/opencode/types.lua
+++ b/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
diff --git a/lua/opencode/ui/session_diff.lua b/lua/opencode/ui/session_diff.lua
index 84d850e4..038be4d6 100644
--- a/lua/opencode/ui/session_diff.lua
+++ b/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 +113,15 @@ 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,
   }
-  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 +215,7 @@ 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 +234,6 @@ 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 +250,7 @@ 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()
@@ -388,9 +388,15 @@ 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
 
diff --git a/lua/opencode/ui/session_diff/comment_input.lua b/lua/opencode/ui/session_diff/comment_input.lua
index 906f88d6..0b963516 100644
--- a/lua/opencode/ui/session_diff/comment_input.lua
+++ b/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
 
diff --git a/lua/opencode/ui/session_diff/help.lua b/lua/opencode/ui/session_diff/help.lua
index fb4b3403..e00b1785 100644
--- a/lua/opencode/ui/session_diff/help.lua
+++ b/lua/opencode/ui/session_diff/help.lua
@@ -17,6 +17,9 @@ local action_order = {
   prev_comment = 13,
   submit_comment = 14,
   cancel_comment = 15,
+  next_file = 16,
+  prev_file = 17,
+  select = 18,
 }
 
 ---@class OpencodeSessionDiffHelpSection
@@ -25,13 +28,14 @@ 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 +49,7 @@ 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 = {
diff --git a/tests/unit/keymap_spec.lua b/tests/unit/keymap_spec.lua
index 6f115f1e..9348a139 100644
--- a/tests/unit/keymap_spec.lua
+++ b/tests/unit/keymap_spec.lua
@@ -140,6 +140,46 @@ describe('opencode.keymap', function()
     package.loaded['opencode.config'] = nil
   end)
 
+  describe('local actions', function()
+    it('prefers local overrides and passes fresh arguments on each invocation', function()
+      local arguments = { { value = 'original' } }
+      local received = {}
+      keymap.setup_window_keymaps({ x = { 'toggle', arguments, mode = 'n', nowait = true } }, 0, false, {
+        toggle = function(value)
+          received[#received + 1] = value.value
+          value.value = 'changed'
+        end,
+      })
+      set_keymaps[1].callback()
+      set_keymaps[1].callback()
+      assert.same({ 'original', 'original' }, received)
+      assert.equals(0, #executed_parsed)
+      assert.equals('', set_keymaps[1].opts.desc)
+      assert.is_true(set_keymaps[1].opts.nowait)
+      assert.equals('n', set_keymaps[1].modes)
+    end)
+
+    it('falls back to panel commands for names outside the local action table', function()
+      keymap.setup_window_keymaps({ x = { 'toggle' } }, 0, false, {})
+      set_keymaps[1].callback()
+      assert.equals('toggle', executed_parsed[1].intent.name)
+    end)
+
+    it('passes configured arguments to custom callbacks', function()
+      local received
+      keymap.setup_window_keymaps({
+        x = {
+          function(value)
+            received = value
+          end,
+          { 'argument' },
+        },
+      }, 0)
+      set_keymaps[1].callback()
+      assert.equals('argument', received)
+    end)
+  end)
+
   describe('panel lifecycle', function()
     local function panel()
       local windows = { input_win = vim.api.nvim_get_current_win(), output_win = vim.api.nvim_get_current_win() }
diff --git a/tests/unit/session_diff_comment_input_spec.lua b/tests/unit/session_diff_comment_input_spec.lua
index 583e1478..157f1a62 100644
--- a/tests/unit/session_diff_comment_input_spec.lua
+++ b/tests/unit/session_diff_comment_input_spec.lua
@@ -1,6 +1,23 @@
 local comment_input = require('opencode.ui.session_diff.comment_input')
 
 describe('session diff comment input', function()
+  it('accepts custom callbacks with arguments in comment mappings', function()
+    local config = require('opencode.config')
+    local received
+    config.keymap.session_diff.comment['X'] = {
+      function(value)
+        received = value
+      end,
+      { 'comment callback' },
+    }
+    comment_input.open({ title = 'file.lua:1-1 (after)', on_submit = function() end })
+    config.keymap.session_diff.comment['X'] = nil
+    vim.cmd('stopinsert')
+    vim.api.nvim_feedkeys('X', 'xt', false)
+    assert.equals('comment callback', received)
+    vim.api.nvim_feedkeys('q', 'xt', false)
+  end)
+
   it('submits a written comment from the real acwrite float', function()
     local origin = vim.api.nvim_get_current_win()
     local submitted
@@ -18,11 +35,11 @@ describe('session diff comment input', function()
     assert.equals(origin, vim.api.nvim_get_current_win())
   end)
 
-  it('keeps temporary comment editor free of filetype hooks', function()
+  it('identifies the temporary comment editor with a dedicated filetype', function()
     local triggered = false
     local group = vim.api.nvim_create_augroup('OpencodeCommentInputSpec', { clear = true })
     vim.api.nvim_create_autocmd('FileType', {
-      pattern = '*',
+      pattern = 'opencode_diff_comment',
       group = group,
       callback = function(args)
         if vim.bo[args.buf].buftype == 'acwrite' then
@@ -33,9 +50,9 @@ describe('session diff comment input', function()
     comment_input.open({ title = 'file.lua:1-1 (after)', on_submit = function() end })
     local buf = vim.api.nvim_get_current_buf()
     assert.equals('acwrite', vim.bo[buf].buftype)
-    assert.equals('', vim.bo[buf].filetype)
+    assert.equals('opencode_diff_comment', vim.bo[buf].filetype)
     assert.is_false(vim.b[buf].completion)
-    assert.is_false(triggered)
+    assert.is_true(triggered)
     vim.api.nvim_win_close(vim.api.nvim_get_current_win(), true)
     vim.api.nvim_del_augroup_by_id(group)
   end)
diff --git a/tests/unit/session_diff_spec.lua b/tests/unit/session_diff_spec.lua
index cf9f1183..ea951e02 100644
--- a/tests/unit/session_diff_spec.lua
+++ b/tests/unit/session_diff_spec.lua
@@ -34,6 +34,7 @@ describe('session diff', function()
       end,
     })
     local list_buf = vim.api.nvim_get_current_buf()
+    assert.equals('opencode_diff_list', vim.bo[list_buf].filetype)
     local function mapped(buf, key)
       return vim.tbl_contains(
         vim.tbl_map(function(entry)
@@ -46,6 +47,8 @@ describe('session diff', function()
     assert.is_false(mapped(list_buf, 'p'))
     local preview_win = vim.api.nvim_tabpage_list_wins(0)[2]
     local preview_buf = vim.api.nvim_win_get_buf(preview_win)
+    assert.equals('lua.opencode_diff_preview', vim.bo[preview_buf].filetype)
+    assert.equals('lua', vim.bo[preview_buf].syntax)
     assert.is_true(mapped(preview_buf, 'v'))
     assert.is_false(mapped(preview_buf, 'p'))
 
@@ -54,16 +57,67 @@ describe('session diff', function()
       return vim.api.nvim_get_current_buf() ~= list_buf
     end))
     local turns_buf = vim.api.nvim_get_current_buf()
+    assert.equals('opencode_diff_messages', vim.bo[turns_buf].filetype)
     assert.is_true(mapped(turns_buf, 's'))
     assert.is_false(mapped(turns_buf, 'f'))
     assert.equals(' Messages  (s/t mark, <CR> apply, <Esc> close) ', vim.api.nvim_win_get_config(0).title[1][1])
     diff.show_turn_preview()
     local message_buf = vim.api.nvim_get_current_buf()
+    assert.equals('markdown.opencode_diff_message_preview', vim.bo[message_buf].filetype)
     assert.is_true(mapped(message_buf, 'x'))
     assert.is_false(mapped(message_buf, 'q'))
     assert.is_false(mapped(message_buf, 'p'))
   end)
 
+  it('binds custom callbacks and file navigation with arguments', function()
+    local received
+    config.keymap.session_diff.preview['X'] = {
+      function(value)
+        received = value
+      end,
+      { 'custom argument' },
+      desc = 'Custom preview action',
+    }
+    config.keymap.session_diff.preview['N'] = { 'select', { 1 } }
+    local cwd = vim.fn.getcwd()
+    diff.open({
+      file(cwd .. '/one.lua', '@@ -1 +1 @@\n-old\n+first'),
+      file(cwd .. '/two.lua', '@@ -1 +1 @@\n-old\n+second'),
+    }, { id = 'ses_callbacks' })
+    local list_win = vim.api.nvim_get_current_win()
+    local preview_win = vim.api.nvim_tabpage_list_wins(0)[2]
+    vim.api.nvim_set_current_win(preview_win)
+    vim.api.nvim_feedkeys('X', 'xt', false)
+    assert.equals('custom argument', received)
+    vim.api.nvim_feedkeys('N', 'xt', false)
+    assert.is_true(vim.wo[preview_win].winbar:find('two.lua', 1, true) ~= nil)
+    vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes('<S-Tab>', true, false, true), 'xt', false)
+    assert.is_true(vim.wo[preview_win].winbar:find('one.lua', 1, true) ~= nil)
+    vim.api.nvim_set_current_win(list_win)
+    vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes('<Tab>', true, false, true), 'xt', false)
+    assert.is_true(vim.wo[preview_win].winbar:find('two.lua', 1, true) ~= nil)
+    diff.toggle_help()
+    local lines = table.concat(vim.api.nvim_buf_get_lines(0, 0, -1, false), '\n')
+    assert.is_true(lines:find('Custom preview action', 1, true) ~= nil)
+  end)
+
+  it('allows FileType hooks to override configured buffer-local mappings', function()
+    local called = false
+    local autocmd = vim.api.nvim_create_autocmd('FileType', {
+      pattern = '*.opencode_diff_preview',
+      callback = function(args)
+        vim.keymap.set('n', 'p', function()
+          called = true
+        end, { buffer = args.buf })
+      end,
+    })
+    diff.open({ file(vim.fn.getcwd() .. '/one.lua', '@@ -1 +1 @@\n-old\n+new') }, { id = 'ses_hooks' })
+    vim.api.nvim_del_autocmd(autocmd)
+    vim.api.nvim_set_current_win(vim.api.nvim_tabpage_list_wins(0)[2])
+    vim.api.nvim_feedkeys('p', 'xt', false)
+    assert.is_true(called)
+  end)
+
   it('aligns folders and files at the same tree depth', function()
     local cwd = vim.fn.getcwd()
     diff.open({
@@ -98,6 +152,7 @@ describe('session diff', function()
     assert.is_true(vim.wo[list_win].winbar:find('?', 1, true) ~= nil)
     vim.api.nvim_feedkeys('?', 'xt', false)
     local help_win = vim.api.nvim_get_current_win()
+    assert.equals('opencode_diff_help', vim.bo.filetype)
     assert.not_equals(list_win, help_win)
     local lines = vim.api.nvim_buf_get_lines(0, 0, -1, false)
     assert.is_true(vim.tbl_contains(

From a6fb3776adc404e525dc137a04808292d2374a1f Mon Sep 17 00:00:00 2001
From: Francis Belanger <francis.belanger@gmail.com>
Date: Wed, 7 Oct 2026 08:26:24 -0400
Subject: [PATCH 2/4] fix: disable wrapping in session diff file list

---
 lua/opencode/ui/session_diff.lua | 1 +
 tests/unit/session_diff_spec.lua | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/lua/opencode/ui/session_diff.lua b/lua/opencode/ui/session_diff.lua
index 038be4d6..653be926 100644
--- a/lua/opencode/ui/session_diff.lua
+++ b/lua/opencode/ui/session_diff.lua
@@ -862,6 +862,7 @@ 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)
diff --git a/tests/unit/session_diff_spec.lua b/tests/unit/session_diff_spec.lua
index ea951e02..3ac744a6 100644
--- a/tests/unit/session_diff_spec.lua
+++ b/tests/unit/session_diff_spec.lua
@@ -118,6 +118,15 @@ describe('session diff', function()
     assert.is_true(called)
   end)
 
+  it('disables list wrapping even when enabled globally', function()
+    local wrap = vim.o.wrap
+    vim.o.wrap = true
+    diff.open({ file(vim.fn.getcwd() .. '/one.lua', '@@ -1 +1 @@\n-old\n+new') }, { id = 'ses_wrap' })
+    local list_wrap = vim.wo.wrap
+    vim.o.wrap = wrap
+    assert.is_false(list_wrap)
+  end)
+
   it('aligns folders and files at the same tree depth', function()
     local cwd = vim.fn.getcwd()
     diff.open({

From 5b1bd950a97ed7890aa91c009bc901660b4ef8cb Mon Sep 17 00:00:00 2001
From: Francis Belanger <francis.belanger@gmail.com>
Date: Wed, 7 Oct 2026 08:27:40 -0400
Subject: [PATCH 3/4] feat: open session diff working-tree files with gf

---
 README.md                             |  2 ++
 lua/opencode/config.lua               |  2 ++
 lua/opencode/ui/session_diff.lua      | 22 ++++++++++++++++++++++
 lua/opencode/ui/session_diff/help.lua |  1 +
 tests/unit/session_diff_spec.lua      | 26 ++++++++++++++++++++++++++
 5 files changed, 53 insertions(+)

diff --git a/README.md b/README.md
index b7c6be82..e8957d4c 100644
--- a/README.md
+++ b/README.md
@@ -1191,6 +1191,8 @@ 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. 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.
diff --git a/lua/opencode/config.lua b/lua/opencode/config.lua
index 60679cb4..2e79765e 100644
--- a/lua/opencode/config.lua
+++ b/lua/opencode/config.lua
@@ -33,6 +33,7 @@ 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 },
@@ -51,6 +52,7 @@ 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 },
diff --git a/lua/opencode/ui/session_diff.lua b/lua/opencode/ui/session_diff.lua
index 653be926..1e830697 100644
--- a/lua/opencode/ui/session_diff.lua
+++ b/lua/opencode/ui/session_diff.lua
@@ -120,6 +120,7 @@ local function map_actions(buf, scope)
       M.select(-1)
     end,
     select = M.select,
+    open_file = M.open_file,
   }
   keymaps.setup_window_keymaps(config.keymap.session_diff[scope], buf, false, actions)
 end
@@ -738,6 +739,27 @@ function M.activate()
   vim.api.nvim_win_set_cursor(view.list_win, { row, 0 })
 end
 
+function M.open_file()
+  if not in_view() or #view.files == 0 then
+    return
+  end
+  local index = view.index
+  if vim.api.nvim_get_current_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
+  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))
+end
+
 function M.select(direction)
   if not active() then
     return false
diff --git a/lua/opencode/ui/session_diff/help.lua b/lua/opencode/ui/session_diff/help.lua
index e00b1785..c15fe521 100644
--- a/lua/opencode/ui/session_diff/help.lua
+++ b/lua/opencode/ui/session_diff/help.lua
@@ -20,6 +20,7 @@ local action_order = {
   next_file = 16,
   prev_file = 17,
   select = 18,
+  open_file = 19,
 }
 
 ---@class OpencodeSessionDiffHelpSection
diff --git a/tests/unit/session_diff_spec.lua b/tests/unit/session_diff_spec.lua
index 3ac744a6..49ea5873 100644
--- a/tests/unit/session_diff_spec.lua
+++ b/tests/unit/session_diff_spec.lua
@@ -118,6 +118,32 @@ describe('session diff', function()
     assert.is_true(called)
   end)
 
+  it('opens the working-tree file with gf from the list and preview without replacing snapshots', function()
+    local path = vim.fn.getcwd() .. '/lua/opencode/config.lua'
+    diff.open({ file(path, '@@ -1 +1 @@\n-old\n+new') }, { id = 'ses_gf' })
+    local tab = vim.api.nvim_get_current_tabpage()
+    local list_win = vim.api.nvim_get_current_win()
+    local preview_win = vim.api.nvim_tabpage_list_wins(tab)[2]
+    local preview_buf = vim.api.nvim_win_get_buf(preview_win)
+    for _, win in ipairs({ list_win, preview_win }) do
+      vim.api.nvim_set_current_win(win)
+      vim.api.nvim_feedkeys('gf', 'xt', false)
+      assert.equals(path, vim.api.nvim_buf_get_name(0))
+      assert.not_equals(tab, vim.api.nvim_get_current_tabpage())
+      vim.cmd('tabclose')
+      assert.equals(tab, vim.api.nvim_get_current_tabpage())
+      assert.equals(preview_buf, vim.api.nvim_win_get_buf(preview_win))
+    end
+  end)
+
+  it('does not open a new empty file when gf targets a deleted file', function()
+    local path = vim.fn.getcwd() .. '/missing-session-diff-gf.lua'
+    diff.open({ file(path, '@@ -1 +0,0 @@\n-old') }, { id = 'ses_gf_missing' })
+    local tab = vim.api.nvim_get_current_tabpage()
+    vim.api.nvim_feedkeys('gf', 'xt', false)
+    assert.equals(tab, vim.api.nvim_get_current_tabpage())
+  end)
+
   it('disables list wrapping even when enabled globally', function()
     local wrap = vim.o.wrap
     vim.o.wrap = true

From 1bfd8b01a0349676b5c55cd2c416b24d1d31505e Mon Sep 17 00:00:00 2001
From: Francis Belanger <francis.belanger@gmail.com>
Date: Wed, 7 Oct 2026 08:44:39 -0400
Subject: [PATCH 4/4] feat(session-diff): jump gf to corresponding post-change
 line

Pressing gf from a diff preview or patch pane now opens the working-tree file at the line corresponding to the selected diff line
---
 README.md                        |  2 +-
 lua/opencode/ui/session_diff.lua | 40 ++++++++++++++++++++++++++-
 tests/unit/session_diff_spec.lua | 47 ++++++++++++++++++++++++++++++++
 3 files changed, 87 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index e8957d4c..2f0c7790 100644
--- a/README.md
+++ b/README.md
@@ -1191,7 +1191,7 @@ 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. If the file no longer exists on disk, a warning is shown instead. Remap this using the `open_file` action.
+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
 
diff --git a/lua/opencode/ui/session_diff.lua b/lua/opencode/ui/session_diff.lua
index 1e830697..e5414da1 100644
--- a/lua/opencode/ui/session_diff.lua
+++ b/lua/opencode/ui/session_diff.lua
@@ -405,6 +405,8 @@ 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()
@@ -739,17 +741,52 @@ 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
-  if vim.api.nvim_get_current_win() == view.list_win then
+  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
@@ -758,6 +795,7 @@ function M.open_file()
   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)
diff --git a/tests/unit/session_diff_spec.lua b/tests/unit/session_diff_spec.lua
index 49ea5873..bf1d75d9 100644
--- a/tests/unit/session_diff_spec.lua
+++ b/tests/unit/session_diff_spec.lua
@@ -144,6 +144,53 @@ describe('session diff', function()
     assert.equals(tab, vim.api.nvim_get_current_tabpage())
   end)
 
+  it('maps gf to post-change lines from both sides and unified patches', function()
+    local path = vim.fn.getcwd() .. '/lua/opencode/config.lua'
+    local text = '@@ -1,4 +1,5 @@\n+inserted\n first\n second\n-removed\n+replacement\n last'
+    diff.open({ file(path, text) }, { id = 'ses_gf_lines' })
+    local tab = vim.api.nvim_get_current_tabpage()
+    local before, after
+    for _, win in ipairs(vim.api.nvim_tabpage_list_wins(tab)) do
+      if vim.wo[win].winbar:find('Before:', 1, true) then
+        before = win
+      elseif vim.wo[win].winbar:find('After:', 1, true) then
+        after = win
+      end
+    end
+    local function jump(win, row, expected)
+      assert.is_true(vim.wo[win].number)
+      assert.is_false(vim.wo[win].relativenumber)
+      vim.api.nvim_set_current_win(win)
+      vim.api.nvim_win_set_cursor(win, { row, 0 })
+      vim.api.nvim_feedkeys('gf', 'xt', false)
+      assert.equals(expected, vim.api.nvim_win_get_cursor(0)[1])
+      vim.cmd('tabclose')
+      assert.equals(tab, vim.api.nvim_get_current_tabpage())
+    end
+    jump(before, 2, 3)
+    jump(before, 3, 4)
+    jump(after, 5, 5)
+    diff.show_patch()
+    jump(before, 1, 1)
+    jump(before, 4, 3)
+    jump(before, 5, 4)
+    jump(before, 7, 5)
+  end)
+
+  it('clamps gf line navigation to the current working-tree file length', function()
+    local path = vim.fn.getcwd() .. '/lua/opencode/session_patch.lua'
+    local count = #vim.fn.readfile(path)
+    local text = '@@ -1,100 +1,100 @@\n' .. string.rep(' context\n', 99) .. '-old\n+new'
+    diff.open({ file(path, text) }, { id = 'ses_gf_clamp' })
+    diff.show_patch()
+    local preview = vim.api.nvim_tabpage_list_wins(0)[2]
+    vim.api.nvim_set_current_win(preview)
+    vim.api.nvim_win_set_cursor(preview, { 102, 0 })
+    vim.api.nvim_feedkeys('gf', 'xt', false)
+    assert.equals(count, vim.api.nvim_win_get_cursor(0)[1])
+    vim.cmd('tabclose')
+  end)
+
   it('disables list wrapping even when enabled globally', function()
     local wrap = vim.o.wrap
     vim.o.wrap = true