# Ownership and cleanup

Source: https://libtmux.org/en/go/latest/topics/context-managers/

> Scope-based cleanup for tmux objects, and when your program must kill them explicitly.

A tmux session, window, or pane normally remains until you kill it. Scope-based
cleanup can kill it when your code leaves a block, including after an exception.
See [Workspaces](https://libtmux.org/en/go/latest/concepts/workspaces/) for a temporary layout example.

## Defer cleanup with a fresh context

A [`Session`](<https://libtmux.org/en/go/latest/reference/tmux-session/>), [`Window`](<https://libtmux.org/en/go/latest/reference/tmux-window/>), or [`Pane`](<https://libtmux.org/en/go/latest/reference/tmux-pane/>) handle does not own its tmux object. Dropping
the value leaves tmux running. Register cleanup after successful creation and
use a separate, bounded context so cancellation of the work cannot prevent
cleanup. Return cleanup failures along with any work failure:

```go
func temporarySession(ctx context.Context, server tmux.Server) (err error) {
    session, err := server.NewSession(ctx, tmux.NewSessionRequest{})
    if err != nil {
        return err
    }
    defer func() {
        cleanup, cancel := context.WithTimeout(context.Background(), time.Second)
        defer cancel()
        err = errors.Join(err, session.Kill(cleanup))
    }()
    _, err = session.SearchWindows(ctx, nil)
    return err
}
```

This function uses `context`, `errors`, `time`, and the [`tmux`](<https://libtmux.org/en/go/latest/reference/#tmux>) package. It owns
only the session it creates. Do not kill a shared server as session cleanup.

[`ControlClient`](<https://libtmux.org/en/go/latest/reference/tmux-controlclient/>), [`PaneObservation`](<https://libtmux.org/en/go/latest/reference/tmux-paneobservation/>), and [`NotificationStream`](<https://libtmux.org/en/go/latest/reference/tmux-notificationstream/>) implement
[`io.Closer`](<https://pkg.go.dev/io#Closer>). Close those resources separately from killing tmux objects.
For tests, [`tmuxtest.NewServer`](<https://libtmux.org/en/go/latest/reference/tmuxtest-newserver/>) registers isolated server cleanup with the
Go test runner.

<a id="what-this-means-in-practice"></a>

## Testing cleanup

Use explicit cleanup for objects whose handles have no disposal hook. For an
entire disposable test server, prefer your port's test fixture or server guard;
see [Testing with libtmux](https://libtmux.org/en/go/latest/guides/testing-with-libtmux/).