v0.53.0 - Bug fixes

A focused maintenance release that fixes a critical bug in Session.attach() that caused tracebacks when users killed sessions while attached via tmuxp load.

Highlights

• Fixed: Session.attach() no longer raises TmuxObjectDoesNotExist when a user kills the session during attachment
• Breaking: Session.attach() no longer calls refresh() after returning (semantically incorrect for interactive commands)

---

Bug Fixes

Session.attach() no longer fails if session killed during attachment (#616)

Fixed an issue where Session.attach() would raise TmuxObjectDoesNotExist when a user:

1. Attaches to a tmux session via tmuxp load
2. Works in the session
3. Kills the session (e.g., closes all windows) before detaching
4. Detaches from tmux

User Experience (Before Fix)

After running tmuxp load, users would see this traceback printed to their terminal after detaching:

Traceback (most recent call last):
  File "~/.local/bin/tmuxp", line 7, in <module>
    sys.exit(cli.cli())
  ...
  File ".../libtmux/session.py", line 332, in attach
    self.refresh()
  File ".../libtmux/neo.py", line 167, in _refresh
    obj = fetch_obj(...)
  File ".../libtmux/neo.py", line 242, in fetch_obj
    raise exc.TmuxObjectDoesNotExist(...)
libtmux.exc.TmuxObjectDoesNotExist: Could not find object

Root Cause

Session.attach() called self.refresh() after the attach-session command returned. Since attach-session is a blocking interactive command, the session state can change arbitrarily during attachment—including being killed entirely.

Technical Details

The refresh() call was semantically incorrect for interactive commands:

• attach-session blocks until user detaches
• Session state can change during attachment (user may kill session, rename it, etc.)
• Refreshing the object after such a command makes no sense—the state could be anything

The fix: Remove the self.refresh() call from Session.attach() (2 lines removed).

---

Breaking Changes

Session.attach() no longer calls refresh() (#616)

Session.attach() previously called Session.refresh() after the attach-session command returned. This was semantically incorrect since attach-session is a blocking interactive command where session state can change arbitrarily during attachment.

This was never strictly defined behavior as libtmux abstracts tmux internals away. Code that relied on the session object being refreshed after attach() should explicitly call session.refresh() if needed.

Migration

# If you relied on the implicit refresh (unlikely):
session.attach()
session.refresh()  # Now explicit if you need it

---

Timeline

Date	Event
Feb 2024	Session.attach() added with refresh() call (9a5147a)
Nov 2025	tmuxp switched from attach_session() to attach() (fdafdd2b)
Dec 2025	Users started experiencing the bug
Dec 2025	v0.53.0 released with fix

---

Installation

pip:

pip install libtmux==0.53.0

uv:

uv add libtmux==0.53.0

pipx (for tmuxp users):

pipx upgrade tmuxp

---

What's Changed

• fix(Session.attach()): Remove refresh() call that fails after session killed by @tony in #616

Full Changelog: v0.52.1...v0.53.0

v0.52.1 - Trusted Publisher for PyPI builds

Development

• ci(release): Migrate to PyPI Trusted Publisher by @tony in #615

Full Changelog: v0.52.0...v0.52.1

v0.52.0 - `send_keys()` updates

libtmux 0.52.0

capture_pane() enhancements

The Pane.capture_pane() method now supports 5 new parameters exposing additional tmux capture-pane flags:

Parameter	tmux Flag	Description
escape_sequences	-e	Include ANSI escape sequences (colors, attributes)
escape_non_printable	-C	Escape non-printable chars as octal \xxx
join_wrapped	-J	Join wrapped lines back together
preserve_trailing	-N	Preserve trailing spaces at line ends
trim_trailing	-T	Trim trailing empty positions (tmux 3.4+)

Examples

Capturing colored output:

# Capture with ANSI escape sequences preserved
pane.send_keys('printf "\\033[31mRED\\033[0m"', enter=True)
output = pane.capture_pane(escape_sequences=True)
# Output contains: '\x1b[31mRED\x1b[0m'

Joining wrapped lines:

# Long lines that wrap are joined back together
output = pane.capture_pane(join_wrapped=True)

Version compatibility

The trim_trailing parameter requires tmux 3.4+. If used with an older version, a warning is issued and the flag is ignored. All other parameters work with libtmux's minimum supported version (tmux 3.2a).

What's Changed

• Capture pane updates by @tony in #614

Full Changelog: v0.51.0...v0.52.0

v0.51.0 (Breaking API deprecations)

Breaking Changes

Deprecate legacy APIs

Legacy API methods (deprecated in v0.16–v0.33) now raise DeprecatedError (hard error) instead of emitting DeprecationWarning.

See the migration guide for full context and examples.

• Deprecate legacy APIs (raise DeprecatedError) by @tony in #611

Method Renamings

Deprecated	Replacement	Class	Deprecated Since
kill_server()	kill()	Server	0.30.0
attach_session()	attach()	Session	0.30.0
kill_session()	kill()	Session	0.30.0
select_window()	select()	Window	0.30.0
kill_window()	kill()	Window	0.30.0
split_window()	split()	Window	0.33.0
select_pane()	select()	Pane	0.30.0
resize_pane()	resize()	Pane	0.28.0
split_window()	split()	Pane	0.33.0

Property Renamings

Deprecated	Replacement	Class	Deprecated Since
attached_window	active_window	Session	0.31.0
attached_pane	active_pane	Session	0.31.0
attached_pane	active_pane	Window	0.31.0

Query/Filter API Changes

Deprecated	Replacement	Class	Deprecated Since
list_sessions() / _list_sessions()	sessions property	Server	0.17.0
list_windows() / _list_windows()	windows property	Session	0.17.0
list_panes() / _list_panes()	panes property	Window	0.17.0
where({...})	.filter(**kwargs) on sessions/windows/panes	All	0.17.0
find_where({...})	.get(default=None, **kwargs) on sessions/windows/panes	All	0.17.0
get_by_id(id)	.get(session_id/window_id/pane_id=..., default=None)	All	0.16.0
children property	sessions/windows/panes	All	0.17.0

Attribute Access Changes

Deprecated	Replacement	Deprecated Since
obj['key']	obj.key	0.17.0
obj.get('key')	obj.key	0.17.0
obj.get('key', None)	getattr(obj, 'key', None)	0.17.0

Still Soft Deprecations (DeprecationWarning)

The following deprecations from v0.50.0 continue to emit DeprecationWarning only:

Deprecated	Replacement	Class
set_window_option()	set_option()	Window
show_window_option()	show_option()	Window
show_window_options()	show_options()	Window
g parameter	global_ parameter	Options & hooks methods

Migration Example

Before (deprecated, now raises DeprecatedError):

# Old method names
server.kill_server()
session.attach_session()
window.split_window()
pane.resize_pane()

# Old query API
server.list_sessions()
session.find_where({'window_name': 'main'})

# Old dict-style access
window['window_name']

After:

# New method names
server.kill()
session.attach()
window.split()
pane.resize()

# New query API
server.sessions
session.windows.get(window_name='main', default=None)

# New attribute access
window.window_name

Links

• API Documentation
• Migration Guide
• Changelog

Full Changelog: v0.50.1...v0.51.0

v0.50.1 - Maintenance release

Documentation

• Doc fixes by @tony in #612

Full Changelog: v0.50.0...v0.50.1

v0.50.0 - options and hook management

libtmux 0.50 brings a major enhancement to option and hook management with a unified, typed API for managing tmux options and hooks across all object types.

Highlights

• Unified Options API: New show_option(), show_options(), set_option(), and unset_option() methods available on Server, Session, Window, and Pane
• Hook Management: Full programmatic control over tmux hooks with support for indexed hook arrays and bulk operations
• SparseArray: New internal data structure for handling tmux's sparse indexed arrays (e.g., command-alias[0], command-alias[99])
• tmux 3.2+ baseline: Removed support for tmux versions below 3.2a, enabling cleaner code and full hook/option feature support

Unified Options API

All tmux objects now share a consistent options interface:

import libtmux

server = libtmux.Server()
session = server.sessions[0]
window = session.windows[0]

# Get all options as a structured dict
session.show_options()
# {'activity-action': 'other', 'base-index': 0, ...}

# Get a single option value
session.show_option('base-index')
# 0

# Set an option
window.set_option('automatic-rename', True)

# Unset an option (revert to default)
window.unset_option('automatic-rename')

Hook Management

Programmatic control over tmux hooks:

session = server.sessions[0]

# Set a hook
session.set_hook('session-renamed', 'display-message "Renamed!"')

# Get hook value (returns SparseArray for indexed hooks)
session.show_hook('session-renamed')
# {0: 'display-message "Renamed!"'}

# Get all hooks
session.show_hooks()

# Remove a hook
session.unset_hook('session-renamed')

# Bulk operations for indexed hooks
session.set_hooks('session-renamed', {
    0: 'display-message "Hook 0"',
    1: 'display-message "Hook 1"',
    5: 'run-shell "echo hook 5"',
})

Breaking Changes

Deprecated Window methods

The following methods are deprecated and will be removed in a future release:

Deprecated	Replacement
Window.set_window_option()	Window.set_option()
Window.show_window_option()	Window.show_option()
Window.show_window_options()	Window.show_options()

Deprecated g parameter

The g parameter for global options is deprecated in favor of global_:

# Before (deprecated)
session.show_option('status', g=True)

# After (0.50.0+)
session.show_option('status', global_=True)

New Constants

• OptionScope enum: Server, Session, Window, Pane
• OPTION_SCOPE_FLAG_MAP: Maps scope to tmux flags (-s, -w, -p)
• HOOK_SCOPE_FLAG_MAP: Maps scope to hook flags

Documentation

• New topic guide: Options and Hooks
• New topic guides: Automation patterns, Workspace setup, Pane interaction, QueryList filtering
• Refreshed README with hero section, quickstart, and more examples

tmux Version Compatibility

Feature	Minimum tmux
All options/hooks features	3.2+
Window/Pane hook scopes (-w, -p)	3.2+
client-active, window-resized hooks	3.3+
pane-title-changed hook	3.5+

What's Changed

• Improved option management, add hook management by @tony in #516
• Refresh README by @tony in #609

Full Changelog: v0.49.0...v0.50.0

v0.49.0 (drop tmux < 3.2)

What's Changed

Breaking: tmux <3.2 fully dropped

• Drop support for tmux versions < 3.2 by @tony in #608

Full Changelog: v0.48.0...v0.49.0

v0.48.0 (deprecating tmux <3.2)

What's Changed

Breaking: tmux <3.2 deprecated

Deprecate old tmux versions by @tony in #606

Development

tmux: Add tmux 3.6 to testgrid by @tony in #607

Full Changelog: v0.47.0...v0.48.0

v0.47.0 - Drop Python 3.9

Breaking changes

• Support Python 3.14 by @tony in #601
• Drop Python 3.9 by @tony in #602

Full Changelog: v0.46.2...v0.47.0

v0.46.2 - `start_directory` typing fix

What's Changed

• Fix new_window argument typing in Session by @Data5tream in #596
  • types: Add StrPath typing, fix new_session by @tony in #597
    • types: Add StrPath typing, fix new_session, part 2 by @tony in #598

New Contributors

• @Data5tream made their first contribution in #596

Full Changelog: v0.46.1...v0.46.2