rmux-server 0.10.0

Tokio daemon and request dispatcher for the RMUX terminal multiplexer.
Documentation
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
use std::time::Duration;

use super::*;
use crate::handler::scripting_support::install_queue_exact_target_capture_pause;
use crate::pane_io::AttachControl;
use tokio::sync::mpsc;

fn create_session_in_state(
    state: &mut crate::pane_terminals::HandlerState,
    name: &str,
) -> SessionName {
    let name = session_name(name);
    state
        .sessions
        .create_session(name.clone(), terminal_size())
        .expect("create session");
    name
}

async fn retained_alert_binding(
    handler: &RequestHandler,
    session_name: &SessionName,
) -> (Option<Target>, std::sync::Arc<LifecycleTargetLease>) {
    let mut state = handler.state.lock().await;
    let event = super::super::super::prepare_lifecycle_event(
        &mut state,
        &rmux_core::LifecycleEvent::AlertActivity {
            target: WindowTarget::with_window(session_name.clone(), 0),
        },
    );
    (
        event.current_target,
        event
            .retained_current_target
            .expect("activity event captures a retained window"),
    )
}

async fn wait_for_pause(pause: &crate::handler::scripting_support::QueueExactTargetCapturePause) {
    tokio::time::timeout(Duration::from_secs(2), pause.reached.notified())
        .await
        .expect("queued command reaches the post-parse pause");
}

#[tokio::test]
async fn parsed_implicit_mutation_revalidates_after_slot_replacement() {
    let handler = RequestHandler::new();
    let session_name = {
        let mut state = handler.state.lock().await;
        create_session_in_state(&mut state, "retained-parse-mutation-race")
    };
    let (current_target, lease) = retained_alert_binding(&handler, &session_name).await;
    let pause = install_queue_exact_target_capture_pause(&handler, "rename-window");
    let command_handler = handler.clone();
    let command = tokio::spawn(async move {
        command_handler
            .execute_hook_command_with_target_binding(
                std::process::id(),
                "rename-window stale-retarget",
                current_target,
                Some(lease),
            )
            .await
    });
    wait_for_pause(&pause).await;

    let replacement_id = {
        let mut state = handler.state.lock().await;
        let session = state
            .sessions
            .session_mut(&session_name)
            .expect("session exists");
        session
            .remove_window_allowing_empty(0)
            .expect("remove parsed target");
        session
            .insert_window_with_initial_pane(0, terminal_size())
            .expect("replace parsed target");
        let replacement_id = session.window_at(0).expect("replacement exists").id();
        state.retire_removed_lifecycle_targets();
        replacement_id
    };
    pause.release.notify_one();

    let error = command
        .await
        .expect("queued command task joins")
        .expect_err("replacement must fail closed");
    assert!(error.to_string().contains("replaced"), "{error}");
    let state = handler.state.lock().await;
    let replacement = state
        .sessions
        .session(&session_name)
        .and_then(|session| session.window_at(0))
        .expect("replacement survives");
    assert_eq!(replacement.id(), replacement_id);
    assert_ne!(replacement.name(), Some("stale-retarget"));
}

#[tokio::test]
async fn implicit_pane_role_revalidates_after_same_window_slot_replacement() {
    let handler = RequestHandler::new();
    let session_name = {
        let mut state = handler.state.lock().await;
        let session_name = create_session_in_state(&mut state, "retained-pane-role");
        state
            .sessions
            .session_mut(&session_name)
            .expect("session exists")
            .split_active_pane()
            .expect("create second pane");
        session_name
    };
    let (current_target, lease) = retained_alert_binding(&handler, &session_name).await;

    handler
        .execute_hook_command_with_target_binding(
            std::process::id(),
            "send-keys",
            current_target.clone(),
            Some(lease.clone()),
        )
        .await
        .expect("a live window lease resolves its implicit pane role");

    let pause = install_queue_exact_target_capture_pause(&handler, "send-keys");
    let command_handler = handler.clone();
    let command = tokio::spawn(async move {
        command_handler
            .execute_hook_command_with_target_binding(
                std::process::id(),
                "send-keys",
                current_target,
                Some(lease),
            )
            .await
    });
    wait_for_pause(&pause).await;

    {
        let mut state = handler.state.lock().await;
        state
            .sessions
            .session_mut(&session_name)
            .expect("session remains live")
            .swap_panes(
                SessionPaneTarget::new(0, 0),
                SessionPaneTarget::new(0, 1),
                PaneSwapOptions::new(true, false),
            )
            .expect("swap pane identities across numeric slots");
    }
    pause.release.notify_one();

    let error = command
        .await
        .expect("send-keys task joins")
        .expect_err("pane slot replacement must fail closed");
    assert!(error.to_string().contains("replaced"), "{error}");
}

#[tokio::test]
async fn implicit_pane_role_rejects_respawned_output_generation() {
    let handler = RequestHandler::new();
    let session_name = create_handler_session(&handler, "retained-pane-respawn").await;
    let target = PaneTarget::with_window(session_name.clone(), 0, 0);
    let (pane_id, initial_generation) = {
        let state = handler.state.lock().await;
        let pane_id = state
            .sessions
            .session(&session_name)
            .and_then(|session| session.window_at(0))
            .and_then(|window| window.pane(0))
            .map(rmux_core::Pane::id)
            .expect("target pane exists");
        (
            pane_id,
            state.pane_output_generation_for_target(&target, pane_id),
        )
    };
    let (current_target, lease) = retained_alert_binding(&handler, &session_name).await;
    let pause = install_queue_exact_target_capture_pause(&handler, "send-keys");
    let command_handler = handler.clone();
    let command = tokio::spawn(async move {
        command_handler
            .execute_hook_command_with_target_binding(
                std::process::id(),
                "send-keys x",
                current_target,
                Some(lease),
            )
            .await
    });
    wait_for_pause(&pause).await;

    let respawned = handler
        .handle(Request::RespawnPane(Box::new(
            rmux_proto::RespawnPaneRequest {
                target: target.clone(),
                kill: true,
                start_directory: None,
                environment: None,
                command: Some(vec![crate::test_shell::stdin_discard_command()]),
                process_command: None,
            },
        )))
        .await;
    assert!(
        matches!(respawned, Response::RespawnPane(_)),
        "{respawned:?}"
    );
    {
        let state = handler.state.lock().await;
        assert_eq!(
            state
                .sessions
                .session(&session_name)
                .and_then(|session| session.window_at(0))
                .and_then(|window| window.pane(0))
                .map(rmux_core::Pane::id),
            Some(pane_id)
        );
        assert_ne!(
            state.pane_output_generation_for_target(&target, pane_id),
            initial_generation
        );
    }
    pause.release.notify_one();

    let error = command
        .await
        .expect("send-keys task joins")
        .expect_err("the retained command must not reach the respawned process");
    assert!(
        error.to_string().contains("target identity changed"),
        "{error}"
    );
}

#[tokio::test]
async fn explicit_send_keys_revalidates_before_copy_mode_effects() {
    let handler = RequestHandler::new();
    let session_name = create_handler_session(&handler, "retained-send-keys-copy-mode").await;
    let split = handler
        .handle(Request::SplitWindow(SplitWindowRequest {
            target: SplitWindowTarget::Session(session_name.clone()),
            direction: SplitDirection::Vertical,
            before: false,
            environment: None,
        }))
        .await;
    assert!(matches!(split, Response::SplitWindow(_)), "{split:?}");
    let target = PaneTarget::with_window(session_name.clone(), 0, 0);
    let (current_target, lease) = retained_alert_binding(&handler, &session_name).await;
    let pause = install_queue_exact_target_capture_pause(&handler, "send-keys");
    let command_handler = handler.clone();
    let command_text = format!("send-keys -t {target} q");
    let command = tokio::spawn(async move {
        command_handler
            .execute_hook_command_with_target_binding(
                std::process::id(),
                &command_text,
                current_target,
                Some(lease),
            )
            .await
    });
    wait_for_pause(&pause).await;

    {
        let mut state = handler.state.lock().await;
        state
            .sessions
            .session_mut(&session_name)
            .expect("session remains live")
            .swap_panes(
                SessionPaneTarget::new(0, 0),
                SessionPaneTarget::new(0, 1),
                PaneSwapOptions::new(true, false),
            )
            .expect("replace the explicit numeric pane slot");
    }
    let entered = handler
        .handle(Request::CopyMode(CopyModeRequest {
            target: Some(target.clone()),
            page_down: false,
            exit_on_scroll: false,
            hide_position: false,
            mouse_drag_start: false,
            cancel_mode: false,
            scrollbar_scroll: false,
            source: None,
            page_up: false,
        }))
        .await;
    assert!(matches!(entered, Response::CopyMode(_)), "{entered:?}");
    pause.release.notify_one();

    let error = command
        .await
        .expect("send-keys task joins")
        .expect_err("replacement must be rejected before copy-mode consumes q");
    assert!(error.to_string().contains("replaced"), "{error}");
    let state = handler.state.lock().await;
    let transcript = state
        .transcript_handle(&target)
        .expect("replacement transcript remains available");
    assert!(
        transcript
            .lock()
            .expect("replacement transcript lock")
            .copy_mode_state()
            .is_some(),
        "rejected send-keys must not cancel copy mode on the replacement pane"
    );
}

#[tokio::test]
async fn join_pane_explicit_source_keeps_retained_destination() {
    let handler = RequestHandler::new();
    let alpha = create_handler_session(&handler, "retained-join-destination").await;
    let beta = create_handler_session(&handler, "retained-join-source").await;
    let (current_target, lease) = retained_alert_binding(&handler, &alpha).await;

    handler
        .execute_hook_command_with_target_binding(
            std::process::id(),
            &format!("join-pane -s {beta}:0.0"),
            current_target,
            Some(lease),
        )
        .await
        .expect("explicit source and retained destination succeed");

    let state = handler.state.lock().await;
    assert_eq!(
        state
            .sessions
            .session(&alpha)
            .and_then(|session| session.window_at(0))
            .map(|window| window.panes().len()),
        Some(2)
    );
    assert!(state.sessions.session(&beta).is_none());
}

#[tokio::test]
async fn join_pane_explicit_destination_keeps_retained_source() {
    let handler = RequestHandler::new();
    let alpha = create_handler_session(&handler, "retained-join-source").await;
    let beta = create_handler_session(&handler, "retained-join-destination").await;
    let (current_target, lease) = retained_alert_binding(&handler, &alpha).await;

    handler
        .execute_hook_command_with_target_binding(
            std::process::id(),
            &format!("join-pane -t {beta}:0.0"),
            current_target,
            Some(lease),
        )
        .await
        .expect("retained source and explicit destination succeed");

    let state = handler.state.lock().await;
    assert!(state.sessions.session(&alpha).is_none());
    assert_eq!(
        state
            .sessions
            .session(&beta)
            .and_then(|session| session.window_at(0))
            .map(|window| window.panes().len()),
        Some(2)
    );
}

#[tokio::test]
async fn join_pane_implicit_source_revalidates_after_slot_replacement() {
    let handler = RequestHandler::new();
    let (alpha, beta) = {
        let mut state = handler.state.lock().await;
        (
            create_session_in_state(&mut state, "retained-join-race-source"),
            create_session_in_state(&mut state, "retained-join-race-destination"),
        )
    };
    let (current_target, lease) = retained_alert_binding(&handler, &alpha).await;
    let pause = install_queue_exact_target_capture_pause(&handler, "join-pane");
    let command_handler = handler.clone();
    let command_text = format!("join-pane -t {beta}:0.0");
    let command = tokio::spawn(async move {
        command_handler
            .execute_hook_command_with_target_binding(
                std::process::id(),
                &command_text,
                current_target,
                Some(lease),
            )
            .await
    });
    wait_for_pause(&pause).await;

    {
        let mut state = handler.state.lock().await;
        let session = state.sessions.session_mut(&alpha).expect("source exists");
        session
            .remove_window_allowing_empty(0)
            .expect("remove implicit source");
        session
            .insert_window_with_initial_pane(0, terminal_size())
            .expect("replace implicit source");
        state.retire_removed_lifecycle_targets();
    }
    pause.release.notify_one();

    let error = command
        .await
        .expect("join task joins")
        .expect_err("replaced implicit source must fail closed");
    assert!(error.to_string().contains("replaced"), "{error}");
    let state = handler.state.lock().await;
    for session_name in [&alpha, &beta] {
        assert_eq!(
            state
                .sessions
                .session(session_name)
                .and_then(|session| session.window_at(0))
                .map(|window| window.panes().len()),
            Some(1)
        );
    }
}

async fn assert_session_command_rejects_stale_window(command_name: &str, command: &str) {
    for replace in [false, true] {
        let handler = RequestHandler::new();
        let session_name = {
            let mut state = handler.state.lock().await;
            let session_name =
                create_session_in_state(&mut state, &format!("retained-{command_name}-{replace}"));
            state
                .sessions
                .session_mut(&session_name)
                .expect("session exists")
                .create_window(terminal_size())
                .expect("create surviving window");
            session_name
        };
        let (current_target, lease) = retained_alert_binding(&handler, &session_name).await;
        let pause = install_queue_exact_target_capture_pause(&handler, command_name);
        let command_handler = handler.clone();
        let command_text = command.to_owned();
        let queued = tokio::spawn(async move {
            command_handler
                .execute_hook_command_with_target_binding(
                    std::process::id(),
                    &command_text,
                    current_target,
                    Some(lease),
                )
                .await
        });
        wait_for_pause(&pause).await;

        {
            let mut state = handler.state.lock().await;
            let session = state
                .sessions
                .session_mut(&session_name)
                .expect("session survives");
            session
                .remove_window_allowing_empty(0)
                .expect("remove retained window");
            if replace {
                session
                    .insert_window_with_initial_pane(0, terminal_size())
                    .expect("replace retained window");
            }
            state.retire_removed_lifecycle_targets();
        }
        pause.release.notify_one();

        let error = queued
            .await
            .expect("session command task joins")
            .expect_err("stale lifecycle window must fail closed");
        let phase = if replace { "replaced" } else { "retired" };
        assert!(error.to_string().contains(phase), "{error}");
    }
}

#[tokio::test]
async fn queued_new_window_rejects_retired_and_replaced_implicit_window() {
    assert_session_command_rejects_stale_window(
        "new-window",
        "new-window -d -n stale-retained-window",
    )
    .await;
}

#[tokio::test]
async fn queued_lock_session_rejects_retired_and_replaced_implicit_window() {
    assert_session_command_rejects_stale_window("lock-session", "lock-session").await;
}

#[tokio::test]
async fn queued_new_window_relative_target_keeps_its_captured_anchor() {
    let handler = RequestHandler::new();
    let session_name = create_handler_session(&handler, "queued-new-window-relative").await;
    let response = handler
        .handle(Request::NewWindow(Box::new(NewWindowRequest {
            target: session_name.clone(),
            name: None,
            detached: true,
            environment: None,
            command: None,
            process_command: None,
            start_directory: None,
            target_window_index: Some(2),
            insert_at_target: false,
        })))
        .await;
    assert!(matches!(response, Response::NewWindow(_)), "{response:?}");
    {
        let mut state = handler.state.lock().await;
        let session = state
            .sessions
            .session_mut(&session_name)
            .expect("session exists");
        session.select_window(0).expect("select relative anchor");
    }
    let (current_target, lease) = retained_alert_binding(&handler, &session_name).await;
    let pause = install_queue_exact_target_capture_pause(&handler, "new-window");
    let queued_handler = handler.clone();
    let command = format!("new-window -d -t {session_name}:+1 -n captured-relative");
    let queued = tokio::spawn(async move {
        queued_handler
            .execute_hook_command_with_target_binding(
                std::process::id(),
                &command,
                current_target,
                Some(lease),
            )
            .await
    });
    wait_for_pause(&pause).await;

    handler
        .state
        .lock()
        .await
        .sessions
        .session_mut(&session_name)
        .expect("session exists")
        .select_window(2)
        .expect("move the live active cursor after capture");
    pause.release.notify_one();
    queued
        .await
        .expect("relative new-window task joins")
        .expect("captured relative destination remains valid");

    let state = handler.state.lock().await;
    let session = state
        .sessions
        .session(&session_name)
        .expect("session exists");
    assert_eq!(
        session.window_at(1).and_then(rmux_core::Window::name),
        Some("captured-relative")
    );
    assert!(session.window_at(3).is_none());
}

#[tokio::test]
async fn queued_new_window_insert_rejects_replaced_before_and_after_anchors() {
    for flag in ["-a", "-b"] {
        let handler = RequestHandler::new();
        let session_name = {
            let mut state = handler.state.lock().await;
            let session_name =
                create_session_in_state(&mut state, &format!("queued-new-window-anchor-{flag}"));
            state
                .sessions
                .session_mut(&session_name)
                .expect("session exists")
                .insert_window_with_initial_pane(1, terminal_size())
                .expect("create neighboring window");
            session_name
        };
        let (current_target, lease) = retained_alert_binding(&handler, &session_name).await;
        let pause = install_queue_exact_target_capture_pause(&handler, "new-window");
        let queued_handler = handler.clone();
        let command = format!("new-window -d {flag} -t {session_name}:0 -n stale-placement-anchor");
        let queued = tokio::spawn(async move {
            queued_handler
                .execute_hook_command_with_target_binding(
                    std::process::id(),
                    &command,
                    current_target,
                    Some(lease),
                )
                .await
        });
        wait_for_pause(&pause).await;

        let replacement_id = {
            let mut state = handler.state.lock().await;
            let session = state
                .sessions
                .session_mut(&session_name)
                .expect("session exists");
            session
                .remove_window_allowing_empty(0)
                .expect("remove captured anchor");
            session
                .insert_window_with_initial_pane(0, terminal_size())
                .expect("replace captured anchor");
            let replacement_id = session.window_at(0).expect("replacement exists").id();
            state.retire_removed_lifecycle_targets();
            replacement_id
        };
        pause.release.notify_one();

        let error = queued
            .await
            .expect("placement new-window task joins")
            .expect_err("replacement anchor must invalidate queued placement");
        assert!(error.to_string().contains("changed"), "{error}");
        let state = handler.state.lock().await;
        let session = state
            .sessions
            .session(&session_name)
            .expect("session exists");
        assert_eq!(
            session.window_at(0).expect("replacement survives").id(),
            replacement_id
        );
        assert!(session
            .windows()
            .values()
            .all(|window| window.name() != Some("stale-placement-anchor")));
    }
}

#[tokio::test]
async fn queued_new_window_kill_revalidates_the_destination_at_replacement() {
    let handler = RequestHandler::new();
    let session_name = create_handler_session(&handler, "queued-new-window-kill-occupant").await;
    let created_spare = handler
        .handle(Request::NewWindow(Box::new(NewWindowRequest {
            target: session_name.clone(),
            name: Some("replacement".to_owned()),
            detached: true,
            environment: None,
            command: None,
            process_command: None,
            start_directory: None,
            target_window_index: Some(1),
            insert_at_target: false,
        })))
        .await;
    assert!(matches!(created_spare, Response::NewWindow(_)));
    let (current_target, lease) = retained_alert_binding(&handler, &session_name).await;
    let pause = install_queue_exact_target_capture_pause(&handler, "new-window");
    let queued_handler = handler.clone();
    let command = format!("new-window -dk -t {session_name}:0 -n stale-kill-window");
    let queued = tokio::spawn(async move {
        queued_handler
            .execute_hook_command_with_target_binding(
                std::process::id(),
                &command,
                current_target,
                Some(lease),
            )
            .await
    });
    wait_for_pause(&pause).await;

    let moved = handler
        .handle_move_window(rmux_proto::MoveWindowRequest {
            source: Some(WindowTarget::with_window(session_name.clone(), 1)),
            target: rmux_proto::MoveWindowTarget::Window(WindowTarget::with_window(
                session_name.clone(),
                0,
            )),
            renumber: false,
            kill_destination: true,
            detached: true,
            after: false,
            before: false,
        })
        .await;
    let replacement_id = match moved {
        Response::MoveWindow(response) => {
            let state = handler.state.lock().await;
            state
                .sessions
                .session(&session_name)
                .and_then(|session| {
                    session.window_at(response.target.expect("move target").window_index())
                })
                .expect("replacement exists")
                .id()
        }
        response => panic!("replacement move failed: {response:?}"),
    };
    let hook = handler
        .handle(Request::SetHookMutation(SetHookMutationRequest {
            scope: ScopeSelector::Global,
            hook: HookName::AfterNewWindow,
            command: Some("set-buffer -b rejected-new-window-hook ran".to_owned()),
            lifecycle: HookLifecycle::Persistent,
            append: false,
            unset: false,
            run_immediately: false,
            index: None,
        }))
        .await;
    assert!(matches!(hook, Response::SetHook(_)), "{hook:?}");
    let mut lifecycle = handler.subscribe_lifecycle_events();
    pause.release.notify_one();

    let error = queued
        .await
        .expect("kill-existing new-window task joins")
        .expect_err("replacement destination must not be killed");
    assert!(error.to_string().contains("changed"), "{error}");
    let state = handler.state.lock().await;
    let replacement = state
        .sessions
        .session(&session_name)
        .and_then(|session| session.window_at(0))
        .expect("replacement destination survives");
    assert_eq!(replacement.id(), replacement_id);
    assert_ne!(replacement.name(), Some("stale-kill-window"));
    let session = state
        .sessions
        .session(&session_name)
        .expect("destination session survives");
    assert_eq!(session.windows().len(), 1);
    assert!(session
        .windows()
        .values()
        .all(|window| window.name() != Some("stale-kill-window")));
    assert!(state
        .buffers
        .show(Some("rejected-new-window-hook"))
        .is_err());
    drop(state);
    assert!(
        lifecycle.try_recv().is_err(),
        "rejected transaction must publish no window lifecycle event"
    );
}

#[tokio::test]
async fn queued_new_window_kill_publishes_only_the_committed_window_identity() {
    let handler = RequestHandler::new();
    let session_name = create_handler_session(&handler, "queued-new-window-transaction").await;
    let hook = handler
        .handle(Request::SetHookMutation(SetHookMutationRequest {
            scope: ScopeSelector::Global,
            hook: HookName::AfterNewWindow,
            command: Some("set-buffer -b committed-new-window-hook ran".to_owned()),
            lifecycle: HookLifecycle::Persistent,
            append: false,
            unset: false,
            run_immediately: false,
            index: None,
        }))
        .await;
    assert!(matches!(hook, Response::SetHook(_)), "{hook:?}");
    let mut lifecycle = handler.subscribe_lifecycle_events();
    let (current_target, lease) = retained_alert_binding(&handler, &session_name).await;
    let lifecycle_pause = handler.install_window_lifecycle_emit_pause();
    let queued_handler = handler.clone();
    let command = format!("new-window -dk -t {session_name}:0 -n committed-window");
    let queued = tokio::spawn(async move {
        queued_handler
            .execute_hook_command_with_target_binding(
                std::process::id(),
                &command,
                current_target,
                Some(lease),
            )
            .await
    });
    tokio::time::timeout(Duration::from_secs(2), lifecycle_pause.reached.notified())
        .await
        .expect("committed move reaches lifecycle publication");
    {
        let state = handler.state.lock().await;
        let session = state
            .sessions
            .session(&session_name)
            .expect("session survives");
        assert_eq!(
            session.windows().len(),
            1,
            "temporary window must be gone before lifecycle publication"
        );
        assert_eq!(
            session.window_at(0).and_then(rmux_core::Window::name),
            Some("committed-window")
        );
        assert!(
            state
                .buffers
                .show(Some("committed-new-window-hook"))
                .is_err(),
            "after-new-window must wait for the committed lifecycle effects"
        );
    }
    lifecycle_pause.release.notify_one();
    queued
        .await
        .expect("transactional replacement task joins")
        .expect("transactional replacement succeeds");

    let (committed_target, committed_window_id) = {
        let state = handler.state.lock().await;
        let session = state
            .sessions
            .session(&session_name)
            .expect("session survives");
        assert_eq!(session.windows().len(), 1);
        let committed = session.window_at(0).expect("committed window exists");
        assert_eq!(committed.name(), Some("committed-window"));
        assert_eq!(
            state
                .buffers
                .show(Some("committed-new-window-hook"))
                .expect("after-new-window runs once")
                .1,
            b"ran"
        );
        (
            WindowTarget::with_window(session_name.clone(), 0),
            committed.id(),
        )
    };
    let mut observed = Vec::new();
    while let Ok(event) = lifecycle.try_recv() {
        match event.event {
            rmux_core::LifecycleEvent::WindowLinked { target, .. } => {
                assert_eq!(target, Some(committed_target.clone()));
                observed.push("linked");
            }
            rmux_core::LifecycleEvent::WindowUnlinked { window_id, .. } => {
                assert_eq!(window_id, Some(committed_window_id.as_u32()));
                observed.push("unlinked");
            }
            _ => {}
        }
    }
    assert_eq!(
        observed,
        ["linked", "unlinked"],
        "tmux 3.7b publishes the final WindowId as linked then unlinked before after-new-window"
    );
}

#[tokio::test]
async fn implicit_session_role_rejects_a_post_parse_alias_move() {
    let handler = RequestHandler::new();
    let (alpha, beta) = {
        let mut state = handler.state.lock().await;
        let alpha = create_session_in_state(&mut state, "retained-alias-move-alpha");
        let beta = create_session_in_state(&mut state, "retained-alias-move-beta");
        state
            .sessions
            .session_mut(&alpha)
            .expect("source session exists")
            .create_window(terminal_size())
            .expect("source session keeps a spare window");
        let retained_window = state
            .sessions
            .session(&alpha)
            .and_then(|session| session.window_at(0))
            .cloned()
            .expect("retained window exists");
        state
            .sessions
            .session_mut(&beta)
            .expect("alias session exists")
            .link_window(1, retained_window, false, false)
            .expect("link retained window into alias session");
        (alpha, beta)
    };
    let (current_target, lease) = retained_alert_binding(&handler, &alpha).await;
    let pause = install_queue_exact_target_capture_pause(&handler, "new-window");
    let command_handler = handler.clone();
    let queued = tokio::spawn(async move {
        command_handler
            .execute_hook_command_with_target_binding(
                std::process::id(),
                "new-window -d -n stale-alias",
                current_target,
                Some(lease),
            )
            .await
    });
    wait_for_pause(&pause).await;

    {
        let mut state = handler.state.lock().await;
        state
            .sessions
            .session_mut(&alpha)
            .expect("source session survives")
            .remove_window_allowing_empty(0)
            .expect("unlink parsed alias while stable window survives elsewhere");
        state.retire_removed_lifecycle_targets();
    }
    pause.release.notify_one();

    let error = queued
        .await
        .expect("alias move task joins")
        .expect_err("post-parse alias move must invalidate the immutable witness");
    assert!(error.to_string().contains("changed"), "{error}");
    let state = handler.state.lock().await;
    assert_eq!(
        state
            .sessions
            .session(&alpha)
            .expect("source session remains")
            .windows()
            .len(),
        1
    );
    assert!(state
        .sessions
        .session(&beta)
        .and_then(|session| session.window_at(1))
        .is_some());
}

async fn assert_read_rejects_replaced_target(command_name: &str, command: &str) {
    let handler = RequestHandler::new();
    let session_name = {
        let mut state = handler.state.lock().await;
        create_session_in_state(&mut state, &format!("retained-read-{command_name}"))
    };
    let (current_target, lease) = retained_alert_binding(&handler, &session_name).await;
    let pause = install_queue_exact_target_capture_pause(&handler, command_name);
    let command_handler = handler.clone();
    let command_text = command.to_owned();
    let queued = tokio::spawn(async move {
        command_handler
            .execute_hook_command_with_target_binding(
                std::process::id(),
                &command_text,
                current_target,
                Some(lease),
            )
            .await
    });
    wait_for_pause(&pause).await;

    {
        let mut state = handler.state.lock().await;
        let session = state
            .sessions
            .session_mut(&session_name)
            .expect("session exists");
        session
            .remove_window_allowing_empty(0)
            .expect("remove parsed read target");
        session
            .insert_window_with_initial_pane(0, terminal_size())
            .expect("replace parsed read target");
        state.retire_removed_lifecycle_targets();
    }
    pause.release.notify_one();

    let error = queued
        .await
        .expect("read task joins")
        .expect_err("stale read must fail closed");
    assert!(error.to_string().contains("replaced"), "{error}");
}

#[tokio::test]
async fn display_message_read_revalidates_after_slot_replacement() {
    assert_read_rejects_replaced_target(
        "display-message",
        "display-message -p '#{window_id}:#{pane_id}'",
    )
    .await;
}

#[tokio::test]
async fn target_client_display_follows_the_captured_registration_not_the_lifecycle_target() {
    let handler = RequestHandler::new();
    let lifecycle = create_handler_session(&handler, "display-client-lifecycle").await;
    let before_switch = create_handler_session(&handler, "display-client-before-switch").await;
    let after_switch = create_handler_session(&handler, "display-client-after-switch").await;
    let attach_pid = 91_941;
    let (control_tx, mut control_rx) = mpsc::unbounded_channel();
    handler
        .register_attach(attach_pid, before_switch, control_tx)
        .await;
    let (current_target, lease) = retained_alert_binding(&handler, &lifecycle).await;
    let pause = install_queue_exact_target_capture_pause(&handler, "display-message");
    let queued_handler = handler.clone();
    let queued = tokio::spawn(async move {
        queued_handler
            .execute_hook_command_with_target_binding(
                std::process::id(),
                &format!("display-message -c {attach_pid} 'format #{{session_name}}'"),
                current_target,
                Some(lease),
            )
            .await
    });
    wait_for_pause(&pause).await;

    let response = handler
        .dispatch(
            attach_pid,
            Request::SwitchClient(rmux_proto::SwitchClientRequest {
                target: after_switch.clone(),
            }),
        )
        .await
        .response;
    assert!(
        matches!(response, Response::SwitchClient(_)),
        "{response:?}"
    );
    while control_rx.try_recv().is_ok() {}
    pause.release.notify_one();
    queued
        .await
        .expect("queued display task joins")
        .expect("the same attach registration remains valid after switching");

    let frame = std::iter::from_fn(|| control_rx.try_recv().ok())
        .find_map(|control| match control {
            AttachControl::Overlay(overlay) => String::from_utf8(overlay.frame).ok(),
            _ => None,
        })
        .expect("target client receives its display overlay");
    assert!(
        frame.contains("format display-client-after-switch"),
        "{frame:?}"
    );
    assert!(!frame.contains(lifecycle.as_str()), "{frame:?}");
}

#[tokio::test]
async fn target_client_display_rejects_a_recreated_attach_registration() {
    let handler = RequestHandler::new();
    let lifecycle = create_handler_session(&handler, "display-client-recreate-lifecycle").await;
    let original = create_handler_session(&handler, "display-client-recreate-original").await;
    let replacement = create_handler_session(&handler, "display-client-recreate-replacement").await;
    let attach_pid = 91_942;
    let (original_tx, _original_rx) = mpsc::unbounded_channel();
    handler
        .register_attach(attach_pid, original, original_tx)
        .await;
    let (current_target, lease) = retained_alert_binding(&handler, &lifecycle).await;
    let pause = install_queue_exact_target_capture_pause(&handler, "display-message");
    let queued_handler = handler.clone();
    let queued = tokio::spawn(async move {
        queued_handler
            .execute_hook_command_with_target_binding(
                std::process::id(),
                &format!("display-message -c {attach_pid} 'stale #{{session_name}}'"),
                current_target,
                Some(lease),
            )
            .await
    });
    wait_for_pause(&pause).await;

    let (replacement_tx, mut replacement_rx) = mpsc::unbounded_channel();
    handler
        .register_attach(attach_pid, replacement, replacement_tx)
        .await;
    pause.release.notify_one();

    let error = queued
        .await
        .expect("queued display task joins")
        .expect_err("a replacement registration must not inherit queued client work");
    assert!(error.to_string().contains("disappeared"), "{error}");
    assert!(
        std::iter::from_fn(|| replacement_rx.try_recv().ok())
            .all(|control| !matches!(control, AttachControl::Overlay(_))),
        "replacement attach must not receive the stale overlay"
    );
}

#[tokio::test]
async fn capture_pane_read_revalidates_after_slot_replacement() {
    assert_read_rejects_replaced_target("capture-pane", "capture-pane -p").await;
}

#[tokio::test]
async fn explicit_target_bypasses_retired_lifecycle_role_and_remains_pinned() {
    for replace in [false, true] {
        let handler = RequestHandler::new();
        let alpha = create_handler_session(&handler, &format!("retained-explicit-{replace}")).await;
        let beta =
            create_handler_session(&handler, &format!("explicit-destination-{replace}")).await;
        let (current_target, lease) = retained_alert_binding(&handler, &alpha).await;
        {
            let mut state = handler.state.lock().await;
            let session = state.sessions.session_mut(&alpha).expect("source exists");
            session
                .remove_window_allowing_empty(0)
                .expect("remove implicit lifecycle window");
            if replace {
                session
                    .insert_window_with_initial_pane(0, terminal_size())
                    .expect("replace implicit lifecycle window");
            }
            state.retire_removed_lifecycle_targets();
        }

        handler
            .execute_hook_command_with_target_binding(
                std::process::id(),
                &format!("rename-window -t {beta}:0 explicit-target"),
                current_target,
                Some(lease),
            )
            .await
            .expect("explicit target bypasses stale implicit lifecycle role");

        let state = handler.state.lock().await;
        assert_eq!(
            state
                .sessions
                .session(&beta)
                .and_then(|session| session.window_at(0))
                .and_then(rmux_core::Window::name),
            Some("explicit-target")
        );
    }
}