From 05a642b7a92a14006dcbbf15ca95068b7d0ee2ac Mon Sep 17 00:00:00 2001
From: unkin-agent <unkin-agent@unkin.net>
Date: Sat, 5 Sep 2026 11:19:42 +1000
Subject: [PATCH 1/3] feat(nvim): add git worktree picker that follows open
 buffers

Adds a telescope picker over 'git worktree list --porcelain'. Selecting an
entry cds to that worktree and re-points every open buffer at the same
relative path there, keeping cursor position and refusing to clobber
unsaved work.

Signed-off-by: unkin-agent <unkin-agent@unkin.net>
---
 .config/nvim/lua/func.lua                     |   1 +
 .config/nvim/lua/func/worktree.lua            | 359 ++++++++++++++++++
 .../lua/telescope/_extensions/worktree.lua    |  14 +
 .config/nvim/tests/minimal.lua                |  15 +
 .config/nvim/tests/worktree_spec.lua          | 175 +++++++++
 5 files changed, 564 insertions(+)
 create mode 100644 .config/nvim/lua/func/worktree.lua
 create mode 100644 .config/nvim/lua/telescope/_extensions/worktree.lua
 create mode 100644 .config/nvim/tests/minimal.lua
 create mode 100644 .config/nvim/tests/worktree_spec.lua

diff --git a/.config/nvim/lua/func.lua b/.config/nvim/lua/func.lua
index 1ea8a25..bc63334 100644
--- a/.config/nvim/lua/func.lua
+++ b/.config/nvim/lua/func.lua
@@ -6,6 +6,7 @@ require('func.tabline')
 require('func.popterm')
 require('func.sessions')
 require('func.findfile')
+require('func.worktree')
 
 --  vim.cmd [[
 --    augroup lang_all
diff --git a/.config/nvim/lua/func/worktree.lua b/.config/nvim/lua/func/worktree.lua
new file mode 100644
index 0000000..3fe9a01
--- /dev/null
+++ b/.config/nvim/lua/func/worktree.lua
@@ -0,0 +1,359 @@
+--[[ func/worktree.lua ]]
+--
+-- Telescope picker over `git worktree list`. Picking an entry cds to that
+-- worktree and re-points every open buffer at the same relative path inside it.
+--
+--   <Leader>gw   pick a worktree
+--   :Worktree [path]
+--   :Telescope worktree
+
+local M = {}
+
+local uv = vim.uv or vim.loop
+
+local function notify(msg, level)
+  vim.notify(msg, level or vim.log.levels.INFO, { title = 'worktree' })
+end
+
+local function normalise(path)
+  if path == nil or path == '' then
+    return nil
+  end
+  local resolved = uv.fs_realpath(path) or path
+  local trimmed = resolved:gsub('/+$', '')
+  return trimmed
+end
+
+local function contains(root, path)
+  return path == root or path:sub(1, #root + 1) == root .. '/'
+end
+
+-- git commands run against the current buffer's directory, not just the cwd,
+-- so the picker still works after wandering into another repo.
+local function context_dir()
+  local name = vim.api.nvim_buf_get_name(0)
+  if name ~= '' and vim.bo.buftype == '' then
+    local dir = vim.fn.fnamemodify(name, ':p:h')
+    if vim.fn.isdirectory(dir) == 1 then
+      return dir
+    end
+  end
+  return vim.fn.getcwd()
+end
+
+local function git(dir, args)
+  local cmd = { 'git', '-C', dir }
+  vim.list_extend(cmd, args)
+  local out = vim.fn.systemlist(cmd)
+  if vim.v.shell_error ~= 0 then
+    return nil, table.concat(out, ' ')
+  end
+  return out
+end
+
+function M.list(dir)
+  dir = dir or context_dir()
+  local out, err = git(dir, { 'worktree', 'list', '--porcelain' })
+  if not out then
+    return nil, err
+  end
+
+  local trees, current = {}, nil
+  for _, line in ipairs(out) do
+    if line:match('^worktree ') then
+      current = { path = normalise(line:sub(10)) }
+      table.insert(trees, current)
+    elseif current then
+      if line == 'bare' then
+        current.bare = true
+      elseif line == 'detached' then
+        current.detached = true
+      elseif line:match('^HEAD ') then
+        current.head = line:sub(6)
+      elseif line:match('^branch ') then
+        current.branch = line:sub(8):gsub('^refs/heads/', '')
+      elseif line:match('^locked') then
+        current.locked = true
+      end
+    end
+  end
+  return trees
+end
+
+function M.label(tree)
+  if tree.bare then
+    return '(bare)'
+  end
+  if tree.branch then
+    return tree.branch
+  end
+  if tree.head then
+    return '(detached ' .. tree.head:sub(1, 7) .. ')'
+  end
+  return '(unknown)'
+end
+
+local function detect_root(dir)
+  local out = git(dir, { 'rev-parse', '--show-toplevel' })
+  if out and out[1] and out[1] ~= '' then
+    return normalise(out[1])
+  end
+  return nil
+end
+
+local function listed_file_buffers()
+  local bufs = {}
+  for _, buf in ipairs(vim.api.nvim_list_bufs()) do
+    if vim.api.nvim_buf_is_valid(buf) and vim.bo[buf].buflisted and vim.bo[buf].buftype == '' then
+      local name = vim.api.nvim_buf_get_name(buf)
+      if name ~= '' then
+        table.insert(bufs, { buf = buf, name = normalise(name) or name })
+      end
+    end
+  end
+  return bufs
+end
+
+local function windows_for(buf)
+  local wins = {}
+  for _, win in ipairs(vim.api.nvim_list_wins()) do
+    if vim.api.nvim_win_is_valid(win) and vim.api.nvim_win_get_buf(win) == buf then
+      table.insert(wins, win)
+    end
+  end
+  return wins
+end
+
+local function restore_cursor(win, buf, cursor)
+  local row = math.min(cursor[1], vim.api.nvim_buf_line_count(buf))
+  local line = vim.api.nvim_buf_get_lines(buf, row - 1, row, false)[1] or ''
+  pcall(vim.api.nvim_win_set_cursor, win, { row, math.min(cursor[2], #line) })
+end
+
+local function names(list)
+  local out = {}
+  for _, item in ipairs(list) do
+    table.insert(out, item.rel)
+  end
+  return out
+end
+
+--- Switch the session to `target` and re-point buffers living under the old root.
+--- Returns a summary table, or nil when the switch was refused.
+function M.switch(target, opts)
+  opts = opts or {}
+  local new_root = normalise(target)
+  if not new_root or vim.fn.isdirectory(new_root) == 0 then
+    notify('not a directory: ' .. tostring(target), vim.log.levels.ERROR)
+    return nil
+  end
+
+  local old_root = normalise(opts.from_root)
+    or detect_root(context_dir())
+    or normalise(vim.fn.getcwd())
+
+  if old_root == new_root then
+    notify('already in ' .. new_root)
+    return { root = new_root, moved = {}, missing = {}, kept = {} }
+  end
+
+  local moved, missing, blocked, kept = {}, {}, {}, {}
+  for _, entry in ipairs(listed_file_buffers()) do
+    if contains(old_root, entry.name) and entry.name ~= old_root then
+      local rel = entry.name:sub(#old_root + 2)
+      local item = { buf = entry.buf, rel = rel, dest = new_root .. '/' .. rel }
+      local exists = vim.fn.filereadable(item.dest) == 1
+      if vim.bo[entry.buf].modified then
+        table.insert(exists and blocked or kept, item)
+      elseif exists then
+        table.insert(moved, item)
+      else
+        table.insert(missing, item)
+      end
+    end
+  end
+
+  if #blocked > 0 then
+    notify(
+      'unsaved changes would be replaced; write them first: ' .. table.concat(names(blocked), ', '),
+      vim.log.levels.ERROR
+    )
+    return nil
+  end
+
+  vim.cmd('cd ' .. vim.fn.fnameescape(new_root))
+
+  for _, item in ipairs(moved) do
+    local wins = windows_for(item.buf)
+    local cursor
+    if #wins > 0 then
+      cursor = vim.api.nvim_win_get_cursor(wins[1])
+    else
+      local mark = vim.api.nvim_buf_get_mark(item.buf, '"')
+      if mark[1] > 0 then
+        cursor = mark
+      end
+    end
+
+    local newbuf = vim.fn.bufadd(item.dest)
+    vim.fn.bufload(newbuf)
+    vim.bo[newbuf].buflisted = true
+
+    -- The `"` mark is what a hidden buffer is re-opened at, so carry it too.
+    if cursor then
+      local row = math.min(cursor[1], vim.api.nvim_buf_line_count(newbuf))
+      pcall(vim.api.nvim_buf_set_mark, newbuf, '"', row, cursor[2], {})
+    end
+
+    for _, win in ipairs(wins) do
+      vim.api.nvim_win_set_buf(win, newbuf)
+      if cursor then
+        restore_cursor(win, newbuf, cursor)
+      end
+    end
+
+    if newbuf ~= item.buf and vim.api.nvim_buf_is_valid(item.buf) then
+      pcall(vim.api.nvim_buf_delete, item.buf, { force = false })
+    end
+  end
+
+  -- Buffers with no counterpart keep pointing at the old worktree; flag them
+  -- so it is obvious why they did not follow.
+  for _, list in ipairs({ missing, kept }) do
+    for _, item in ipairs(list) do
+      if vim.api.nvim_buf_is_valid(item.buf) then
+        vim.b[item.buf].worktree_orphan = old_root
+      end
+    end
+  end
+
+  local summary = {
+    root = new_root,
+    previous = old_root,
+    moved = names(moved),
+    missing = names(missing),
+    kept = names(kept),
+  }
+
+  local msg = ('switched to %s (%d buffer(s) moved)'):format(new_root, #moved)
+  local level = vim.log.levels.INFO
+  if #missing > 0 then
+    msg = msg .. '; no counterpart there: ' .. table.concat(summary.missing, ', ')
+    level = vim.log.levels.WARN
+  end
+  if #kept > 0 then
+    msg = msg .. '; left unsaved on old worktree: ' .. table.concat(summary.kept, ', ')
+    level = vim.log.levels.WARN
+  end
+  notify(msg, level)
+
+  return summary
+end
+
+local function selectable(dir)
+  local trees, err = M.list(dir)
+  if not trees then
+    notify('no git worktrees here: ' .. (err or 'not a git repository'), vim.log.levels.ERROR)
+    return nil
+  end
+  local usable = {}
+  for _, tree in ipairs(trees) do
+    if not tree.bare and tree.path and vim.fn.isdirectory(tree.path) == 1 then
+      table.insert(usable, tree)
+    end
+  end
+  if #usable == 0 then
+    notify('no checked-out worktrees to switch to', vim.log.levels.WARN)
+    return nil
+  end
+  return usable
+end
+
+function M.pick(opts)
+  opts = opts or {}
+  local usable = selectable(opts.cwd or context_dir())
+  if not usable then
+    return
+  end
+
+  local ok, pickers = pcall(require, 'telescope.pickers')
+  if not ok then
+    vim.ui.select(usable, {
+      prompt = 'Git worktree',
+      format_item = function(tree)
+        return M.label(tree) .. '  ' .. vim.fn.fnamemodify(tree.path, ':~')
+      end,
+    }, function(choice)
+      if choice then
+        M.switch(choice.path)
+      end
+    end)
+    return
+  end
+
+  local finders = require('telescope.finders')
+  local conf = require('telescope.config').values
+  local actions = require('telescope.actions')
+  local action_state = require('telescope.actions.state')
+  local entry_display = require('telescope.pickers.entry_display')
+
+  local width = 0
+  for _, tree in ipairs(usable) do
+    width = math.max(width, #M.label(tree))
+  end
+  local displayer = entry_display.create({
+    separator = '  ',
+    items = { { width = width }, { remaining = true } },
+  })
+
+  pickers
+    .new(opts, {
+      prompt_title = 'Git Worktrees',
+      finder = finders.new_table({
+        results = usable,
+        entry_maker = function(tree)
+          return {
+            value = tree,
+            path = tree.path,
+            ordinal = M.label(tree) .. ' ' .. tree.path,
+            display = function(entry)
+              return displayer({
+                M.label(entry.value),
+                vim.fn.fnamemodify(entry.value.path, ':~'),
+              })
+            end,
+          }
+        end,
+      }),
+      sorter = conf.generic_sorter(opts),
+      attach_mappings = function(prompt_bufnr)
+        actions.select_default:replace(function()
+          local entry = action_state.get_selected_entry()
+          actions.close(prompt_bufnr)
+          if entry then
+            M.switch(entry.value.path)
+          end
+        end)
+        return true
+      end,
+    })
+    :find()
+end
+
+vim.api.nvim_create_user_command('Worktree', function(cmd)
+  if cmd.args ~= '' then
+    M.switch(cmd.args)
+  else
+    M.pick()
+  end
+end, { nargs = '?', complete = 'dir', desc = 'Switch git worktree and follow open buffers' })
+
+vim.keymap.set('n', '<Leader>gw', function()
+  M.pick()
+end, { silent = true, desc = 'Git worktree picker' })
+
+pcall(function()
+  require('telescope').load_extension('worktree')
+end)
+
+return M
diff --git a/.config/nvim/lua/telescope/_extensions/worktree.lua b/.config/nvim/lua/telescope/_extensions/worktree.lua
new file mode 100644
index 0000000..e21fd67
--- /dev/null
+++ b/.config/nvim/lua/telescope/_extensions/worktree.lua
@@ -0,0 +1,14 @@
+--[[ telescope/_extensions/worktree.lua ]]
+
+local telescope = require('telescope')
+
+return telescope.register_extension({
+  exports = {
+    worktree = function(opts)
+      require('func.worktree').pick(opts)
+    end,
+    list = function(opts)
+      require('func.worktree').pick(opts)
+    end,
+  },
+})
diff --git a/.config/nvim/tests/minimal.lua b/.config/nvim/tests/minimal.lua
new file mode 100644
index 0000000..b69f78c
--- /dev/null
+++ b/.config/nvim/tests/minimal.lua
@@ -0,0 +1,15 @@
+--[[ tests/minimal.lua ]]
+--
+--   nvim --headless -u tests/minimal.lua -c "PlenaryBustedDirectory tests/"
+
+local here = debug.getinfo(1, 'S').source:sub(2)
+local config = vim.fn.fnamemodify(here, ':h:h')
+
+vim.opt.runtimepath:prepend(config)
+
+local plenary = vim.fn.expand('~/.local/share/nvim/site/pack/packer/start/plenary.nvim')
+if vim.fn.isdirectory(plenary) == 1 then
+  vim.opt.runtimepath:append(plenary)
+end
+
+vim.cmd('runtime plugin/plenary.vim')
diff --git a/.config/nvim/tests/worktree_spec.lua b/.config/nvim/tests/worktree_spec.lua
new file mode 100644
index 0000000..efb7229
--- /dev/null
+++ b/.config/nvim/tests/worktree_spec.lua
@@ -0,0 +1,175 @@
+--[[ tests/worktree_spec.lua ]]
+
+local worktree = require('func.worktree')
+
+local function sh(cmd)
+  local out = vim.fn.system(cmd)
+  assert(vim.v.shell_error == 0, table.concat(cmd, ' ') .. ' failed: ' .. out)
+  return out
+end
+
+local function write(path, text)
+  vim.fn.mkdir(vim.fn.fnamemodify(path, ':h'), 'p')
+  vim.fn.writefile(vim.split(text, '\n'), path)
+end
+
+local function realpath(path)
+  return (vim.uv or vim.loop).fs_realpath(path)
+end
+
+local function open(path)
+  vim.cmd('edit ' .. vim.fn.fnameescape(path))
+  return vim.api.nvim_get_current_buf()
+end
+
+local function wipe_all()
+  for _, buf in ipairs(vim.api.nvim_list_bufs()) do
+    pcall(vim.api.nvim_buf_delete, buf, { force = true })
+  end
+end
+
+describe('func.worktree', function()
+  local tmp, main, other
+
+  before_each(function()
+    tmp = vim.fn.tempname()
+    vim.fn.mkdir(tmp, 'p')
+    tmp = realpath(tmp)
+    main = tmp .. '/main'
+    other = tmp .. '/other'
+
+    vim.fn.mkdir(main, 'p')
+    sh({ 'git', '-C', main, 'init', '-q', '-b', 'main' })
+    sh({ 'git', '-C', main, 'config', 'user.email', 'test@example.com' })
+    sh({ 'git', '-C', main, 'config', 'user.name', 'test' })
+    write(main .. '/one.txt', 'alpha\nbravo\ncharlie\ndelta')
+    write(main .. '/sub/two.txt', 'two')
+    sh({ 'git', '-C', main, 'add', '-A' })
+    sh({ 'git', '-C', main, 'commit', '-qm', 'init' })
+    sh({ 'git', '-C', main, 'worktree', 'add', '-q', '-b', 'feature', other })
+
+    write(main .. '/main-only.txt', 'only in main')
+    sh({ 'git', '-C', main, 'add', '-A' })
+    sh({ 'git', '-C', main, 'commit', '-qm', 'main only' })
+
+    wipe_all()
+    vim.cmd('cd ' .. vim.fn.fnameescape(main))
+  end)
+
+  after_each(function()
+    wipe_all()
+    vim.cmd('cd /')
+    vim.fn.delete(tmp, 'rf')
+  end)
+
+  it('lists every worktree of the repo', function()
+    local trees = worktree.list(main)
+    assert.equals(2, #trees)
+
+    local branches = {}
+    for _, tree in ipairs(trees) do
+      branches[tree.branch] = tree.path
+    end
+    assert.equals(realpath(main), branches['main'])
+    assert.equals(realpath(other), branches['feature'])
+  end)
+
+  it('reports an error outside a repository', function()
+    local trees, err = worktree.list(tmp)
+    assert.is_nil(trees)
+    assert.is_true(#err > 0)
+  end)
+
+  it('labels detached and bare entries', function()
+    assert.equals('feature', worktree.label({ branch = 'feature' }))
+    assert.equals('(bare)', worktree.label({ bare = true }))
+    assert.equals('(detached abcdef1)', worktree.label({ head = 'abcdef1234567890' }))
+  end)
+
+  it('re-points buffers at the same relative path', function()
+    local one = open(main .. '/one.txt')
+    open(main .. '/sub/two.txt')
+
+    local summary = worktree.switch(other)
+
+    assert.is_not_nil(summary)
+    assert.equals(realpath(other), summary.root)
+    assert.equals(realpath(other), realpath(vim.fn.getcwd()))
+    table.sort(summary.moved)
+    assert.same({ 'one.txt', 'sub/two.txt' }, summary.moved)
+    assert.is_false(vim.api.nvim_buf_is_valid(one))
+
+    local open_names = {}
+    for _, buf in ipairs(vim.api.nvim_list_bufs()) do
+      if vim.bo[buf].buflisted then
+        open_names[vim.api.nvim_buf_get_name(buf)] = true
+      end
+    end
+    assert.is_true(open_names[realpath(other) .. '/one.txt'])
+    assert.is_true(open_names[realpath(other) .. '/sub/two.txt'])
+  end)
+
+  it('keeps the cursor of a displayed buffer', function()
+    open(main .. '/one.txt')
+    vim.api.nvim_win_set_cursor(0, { 3, 2 })
+    local one_win = vim.api.nvim_get_current_win()
+    vim.cmd('split')
+    open(main .. '/sub/two.txt')
+
+    worktree.switch(other)
+
+    assert.equals(realpath(other) .. '/one.txt', vim.api.nvim_buf_get_name(vim.api.nvim_win_get_buf(one_win)))
+    assert.same({ 3, 2 }, vim.api.nvim_win_get_cursor(one_win))
+  end)
+
+  it('carries the last position of a hidden buffer', function()
+    open(main .. '/one.txt')
+    vim.api.nvim_win_set_cursor(0, { 3, 2 })
+    open(main .. '/sub/two.txt')
+
+    worktree.switch(other)
+
+    local mark = vim.api.nvim_buf_get_mark(vim.fn.bufnr(realpath(other) .. '/one.txt'), '"')
+    assert.equals(3, mark[1])
+  end)
+
+  it('leaves and flags buffers with no counterpart', function()
+    local only = open(main .. '/main-only.txt')
+
+    local summary = worktree.switch(other)
+
+    assert.same({ 'main-only.txt' }, summary.missing)
+    assert.is_true(vim.api.nvim_buf_is_valid(only))
+    assert.equals(realpath(main) .. '/main-only.txt', vim.api.nvim_buf_get_name(only))
+    assert.equals(realpath(main), vim.b[only].worktree_orphan)
+  end)
+
+  it('refuses to switch when an unsaved buffer would be replaced', function()
+    open(main .. '/one.txt')
+    vim.api.nvim_buf_set_lines(0, 0, 1, false, { 'dirty' })
+
+    local summary = worktree.switch(other)
+
+    assert.is_nil(summary)
+    assert.equals(realpath(main), realpath(vim.fn.getcwd()))
+    assert.is_true(vim.bo.modified)
+  end)
+
+  it('keeps unsaved buffers that have no counterpart', function()
+    local only = open(main .. '/main-only.txt')
+    vim.api.nvim_buf_set_lines(only, 0, 1, false, { 'dirty' })
+
+    local summary = worktree.switch(other)
+
+    assert.is_not_nil(summary)
+    assert.same({ 'main-only.txt' }, summary.kept)
+    assert.is_true(vim.bo[only].modified)
+    assert.equals(realpath(main) .. '/main-only.txt', vim.api.nvim_buf_get_name(only))
+  end)
+
+  it('is a no-op when the target is the current worktree', function()
+    local summary = worktree.switch(main)
+    assert.same({}, summary.moved)
+    assert.equals(realpath(main), summary.root)
+  end)
+end)
-- 
2.47.3


From b15c8b49d333431541f12640548d11111df99021 Mon Sep 17 00:00:00 2001
From: unkin-agent <unkin-agent@unkin.net>
Date: Tue, 8 Sep 2026 23:18:00 +1000
Subject: [PATCH 2/3] fix(nvim): carry buffers from every sibling worktree

Buffer migration keyed off the active buffer's repo, so a switch made from
an unrelated buffer moved nothing and said nothing.

- Match each buffer against the target's own worktree list, longest root first.
- Warn when open buffers all live outside the repository.
- Capture and restore the cursor per window, not once from the first one.
- Clamp restored cursors to a line the destination buffer has.

Signed-off-by: unkin-agent <unkin-agent@unkin.net>
---
 .config/nvim/lua/func/worktree.lua   | 105 ++++++++++++++++++++-------
 .config/nvim/tests/worktree_spec.lua |  86 +++++++++++++++++++++-
 2 files changed, 162 insertions(+), 29 deletions(-)

diff --git a/.config/nvim/lua/func/worktree.lua b/.config/nvim/lua/func/worktree.lua
index 3fe9a01..ee67d53 100644
--- a/.config/nvim/lua/func/worktree.lua
+++ b/.config/nvim/lua/func/worktree.lua
@@ -124,10 +124,51 @@ local function windows_for(buf)
   return wins
 end
 
-local function restore_cursor(win, buf, cursor)
-  local row = math.min(cursor[1], vim.api.nvim_buf_line_count(buf))
+--- Fit `cursor` to `buf`, which may be shorter or empty. Rows are 1-based.
+function M.clamp_cursor(buf, cursor)
+  local row = math.max(1, math.min(cursor[1], vim.api.nvim_buf_line_count(buf)))
   local line = vim.api.nvim_buf_get_lines(buf, row - 1, row, false)[1] or ''
-  pcall(vim.api.nvim_win_set_cursor, win, { row, math.min(cursor[2], #line) })
+  return { row, math.max(0, math.min(cursor[2], #line)) }
+end
+
+local function restore_cursor(win, buf, cursor)
+  pcall(vim.api.nvim_win_set_cursor, win, M.clamp_cursor(buf, cursor))
+end
+
+--- Every worktree a buffer could be carried away from, longest path first so a
+--- worktree nested inside another one wins the prefix match.
+local function source_roots(new_root, from_root)
+  if from_root then
+    return { from_root }
+  end
+
+  local roots = {}
+  for _, tree in ipairs(M.list(new_root) or {}) do
+    if tree.path and not tree.bare and tree.path ~= new_root then
+      table.insert(roots, tree.path)
+    end
+  end
+
+  if #roots == 0 then
+    local fallback = detect_root(context_dir()) or normalise(vim.fn.getcwd())
+    if fallback and fallback ~= new_root then
+      roots = { fallback }
+    end
+  end
+
+  table.sort(roots, function(a, b)
+    return #a > #b
+  end)
+  return roots
+end
+
+local function root_of(path, roots)
+  for _, root in ipairs(roots) do
+    if path ~= root and contains(root, path) then
+      return root
+    end
+  end
+  return nil
 end
 
 local function names(list)
@@ -138,7 +179,7 @@ local function names(list)
   return out
 end
 
---- Switch the session to `target` and re-point buffers living under the old root.
+--- Switch the session to `target` and re-point buffers living in its sibling worktrees.
 --- Returns a summary table, or nil when the switch was refused.
 function M.switch(target, opts)
   opts = opts or {}
@@ -148,20 +189,15 @@ function M.switch(target, opts)
     return nil
   end
 
-  local old_root = normalise(opts.from_root)
-    or detect_root(context_dir())
-    or normalise(vim.fn.getcwd())
-
-  if old_root == new_root then
-    notify('already in ' .. new_root)
-    return { root = new_root, moved = {}, missing = {}, kept = {} }
-  end
+  local roots = source_roots(new_root, normalise(opts.from_root))
+  local bufs = listed_file_buffers()
 
   local moved, missing, blocked, kept = {}, {}, {}, {}
-  for _, entry in ipairs(listed_file_buffers()) do
-    if contains(old_root, entry.name) and entry.name ~= old_root then
-      local rel = entry.name:sub(#old_root + 2)
-      local item = { buf = entry.buf, rel = rel, dest = new_root .. '/' .. rel }
+  for _, entry in ipairs(bufs) do
+    local root = root_of(entry.name, roots)
+    if root then
+      local rel = entry.name:sub(#root + 2)
+      local item = { buf = entry.buf, root = root, rel = rel, dest = new_root .. '/' .. rel }
       local exists = vim.fn.filereadable(item.dest) == 1
       if vim.bo[entry.buf].modified then
         table.insert(exists and blocked or kept, item)
@@ -173,6 +209,12 @@ function M.switch(target, opts)
     end
   end
 
+  local matched = #moved + #missing + #blocked + #kept
+  if matched == 0 and normalise(vim.fn.getcwd()) == new_root then
+    notify('already in ' .. new_root)
+    return { root = new_root, moved = {}, missing = {}, kept = {} }
+  end
+
   if #blocked > 0 then
     notify(
       'unsaved changes would be replaced; write them first: ' .. table.concat(names(blocked), ', '),
@@ -185,13 +227,18 @@ function M.switch(target, opts)
 
   for _, item in ipairs(moved) do
     local wins = windows_for(item.buf)
-    local cursor
-    if #wins > 0 then
-      cursor = vim.api.nvim_win_get_cursor(wins[1])
+    local cursors = {}
+    for _, win in ipairs(wins) do
+      cursors[win] = vim.api.nvim_win_get_cursor(win)
+    end
+
+    local last
+    if wins[1] then
+      last = cursors[wins[1]]
     else
       local mark = vim.api.nvim_buf_get_mark(item.buf, '"')
       if mark[1] > 0 then
-        cursor = mark
+        last = mark
       end
     end
 
@@ -200,16 +247,14 @@ function M.switch(target, opts)
     vim.bo[newbuf].buflisted = true
 
     -- The `"` mark is what a hidden buffer is re-opened at, so carry it too.
-    if cursor then
-      local row = math.min(cursor[1], vim.api.nvim_buf_line_count(newbuf))
-      pcall(vim.api.nvim_buf_set_mark, newbuf, '"', row, cursor[2], {})
+    if last then
+      local pos = M.clamp_cursor(newbuf, last)
+      pcall(vim.api.nvim_buf_set_mark, newbuf, '"', pos[1], pos[2], {})
     end
 
     for _, win in ipairs(wins) do
       vim.api.nvim_win_set_buf(win, newbuf)
-      if cursor then
-        restore_cursor(win, newbuf, cursor)
-      end
+      restore_cursor(win, newbuf, cursors[win])
     end
 
     if newbuf ~= item.buf and vim.api.nvim_buf_is_valid(item.buf) then
@@ -222,14 +267,14 @@ function M.switch(target, opts)
   for _, list in ipairs({ missing, kept }) do
     for _, item in ipairs(list) do
       if vim.api.nvim_buf_is_valid(item.buf) then
-        vim.b[item.buf].worktree_orphan = old_root
+        vim.b[item.buf].worktree_orphan = item.root
       end
     end
   end
 
   local summary = {
     root = new_root,
-    previous = old_root,
+    sources = roots,
     moved = names(moved),
     missing = names(missing),
     kept = names(kept),
@@ -237,6 +282,10 @@ function M.switch(target, opts)
 
   local msg = ('switched to %s (%d buffer(s) moved)'):format(new_root, #moved)
   local level = vim.log.levels.INFO
+  if matched == 0 and #bufs > 0 then
+    msg = msg .. ('; %d open buffer(s) live outside this repository'):format(#bufs)
+    level = vim.log.levels.WARN
+  end
   if #missing > 0 then
     msg = msg .. '; no counterpart there: ' .. table.concat(summary.missing, ', ')
     level = vim.log.levels.WARN
diff --git a/.config/nvim/tests/worktree_spec.lua b/.config/nvim/tests/worktree_spec.lua
index efb7229..ffbf9f7 100644
--- a/.config/nvim/tests/worktree_spec.lua
+++ b/.config/nvim/tests/worktree_spec.lua
@@ -28,8 +28,19 @@ local function wipe_all()
   end
 end
 
+local function capture_notify(fn)
+  local seen, orig = {}, vim.notify
+  vim.notify = function(msg, level)
+    table.insert(seen, { msg = msg, level = level })
+  end
+  local ok, err = pcall(fn)
+  vim.notify = orig
+  assert(ok, err)
+  return seen
+end
+
 describe('func.worktree', function()
-  local tmp, main, other
+  local tmp, main, other, outside
 
   before_each(function()
     tmp = vim.fn.tempname()
@@ -37,6 +48,11 @@ describe('func.worktree', function()
     tmp = realpath(tmp)
     main = tmp .. '/main'
     other = tmp .. '/other'
+    outside = tmp .. '/outside'
+
+    vim.fn.mkdir(outside, 'p')
+    sh({ 'git', '-C', outside, 'init', '-q', '-b', 'main' })
+    write(outside .. '/note.txt', 'unrelated')
 
     vim.fn.mkdir(main, 'p')
     sh({ 'git', '-C', main, 'init', '-q', '-b', 'main' })
@@ -172,4 +188,72 @@ describe('func.worktree', function()
     assert.same({}, summary.moved)
     assert.equals(realpath(main), summary.root)
   end)
+
+  it('moves buffers when the active buffer belongs to another repository', function()
+    open(main .. '/one.txt')
+    local stray = open(outside .. '/note.txt')
+
+    local summary = worktree.switch(other)
+
+    assert.is_not_nil(summary)
+    assert.same({ 'one.txt' }, summary.moved)
+    assert.equals(realpath(other) .. '/one.txt', vim.api.nvim_buf_get_name(vim.fn.bufnr(realpath(other) .. '/one.txt')))
+    assert.is_true(vim.api.nvim_buf_is_valid(stray))
+    assert.equals(realpath(outside) .. '/note.txt', vim.api.nvim_buf_get_name(stray))
+  end)
+
+  it('warns instead of silently moving nothing', function()
+    open(outside .. '/note.txt')
+
+    local seen
+    local summary = nil
+    seen = capture_notify(function()
+      summary = worktree.switch(other)
+    end)
+
+    assert.same({}, summary.moved)
+    assert.equals(1, #seen)
+    assert.is_truthy(seen[1].msg:match('outside this repository'))
+    assert.equals(vim.log.levels.WARN, seen[1].level)
+  end)
+
+  it('keeps a per-window cursor when one buffer is in several windows', function()
+    open(main .. '/one.txt')
+    local top = vim.api.nvim_get_current_win()
+    vim.api.nvim_win_set_cursor(top, { 2, 1 })
+    vim.cmd('split')
+    local bottom = vim.api.nvim_get_current_win()
+    vim.api.nvim_win_set_cursor(bottom, { 4, 3 })
+
+    worktree.switch(other)
+
+    local dest = realpath(other) .. '/one.txt'
+    assert.equals(dest, vim.api.nvim_buf_get_name(vim.api.nvim_win_get_buf(top)))
+    assert.equals(dest, vim.api.nvim_buf_get_name(vim.api.nvim_win_get_buf(bottom)))
+    assert.same({ 2, 1 }, vim.api.nvim_win_get_cursor(top))
+    assert.same({ 4, 3 }, vim.api.nvim_win_get_cursor(bottom))
+  end)
+
+  it('clamps a cursor to a position the buffer actually has', function()
+    local buf = vim.api.nvim_create_buf(false, true)
+    assert.same({ 1, 0 }, worktree.clamp_cursor(buf, { 0, 0 }))
+    assert.same({ 1, 0 }, worktree.clamp_cursor(buf, { 9, 4 }))
+    assert.same({ 1, 0 }, worktree.clamp_cursor(buf, { -3, -2 }))
+
+    vim.api.nvim_buf_set_lines(buf, 0, -1, false, { 'alpha', 'bravo' })
+    assert.same({ 2, 5 }, worktree.clamp_cursor(buf, { 7, 9 }))
+    assert.same({ 2, 1 }, worktree.clamp_cursor(buf, { 2, 1 }))
+  end)
+
+  it('lands on a valid line when the destination file is empty', function()
+    vim.fn.writefile({}, other .. '/one.txt')
+    open(main .. '/one.txt')
+    local win = vim.api.nvim_get_current_win()
+    vim.api.nvim_win_set_cursor(win, { 4, 2 })
+
+    worktree.switch(other)
+
+    assert.equals(realpath(other) .. '/one.txt', vim.api.nvim_buf_get_name(vim.api.nvim_win_get_buf(win)))
+    assert.same({ 1, 0 }, vim.api.nvim_win_get_cursor(win))
+  end)
 end)
-- 
2.47.3


From c4dbc24916caed1d7f6c96a8925e8d6b7220fd9f Mon Sep 17 00:00:00 2001
From: unkin-agent <unkin-agent@unkin.net>
Date: Tue, 8 Sep 2026 23:24:33 +1000
Subject: [PATCH 3/3] test(nvim): cover nested worktree resolution

---
 .config/nvim/tests/worktree_spec.lua | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/.config/nvim/tests/worktree_spec.lua b/.config/nvim/tests/worktree_spec.lua
index ffbf9f7..5d0bc2f 100644
--- a/.config/nvim/tests/worktree_spec.lua
+++ b/.config/nvim/tests/worktree_spec.lua
@@ -245,6 +245,19 @@ describe('func.worktree', function()
     assert.same({ 2, 1 }, worktree.clamp_cursor(buf, { 2, 1 }))
   end)
 
+  it('carries a buffer from the innermost worktree containing it', function()
+    local nested = main .. '/nested'
+    sh({ 'git', '-C', main, 'worktree', 'add', '-q', '-b', 'nested', nested })
+    open(nested .. '/one.txt')
+
+    local summary = worktree.switch(other)
+
+    assert.is_not_nil(summary)
+    assert.same({ 'one.txt' }, summary.moved)
+    assert.same({}, summary.missing)
+    assert.equals(realpath(other) .. '/one.txt', vim.api.nvim_buf_get_name(vim.fn.bufnr(realpath(other) .. '/one.txt')))
+  end)
+
   it('lands on a valid line when the destination file is empty', function()
     vim.fn.writefile({}, other .. '/one.txt')
     open(main .. '/one.txt')
-- 
2.47.3