Fix The daemon never reaps its

Pushed 932a218.
rhiza: step rebase: pass
rhiza: step wait-rebased: entered, visit 1
rhiza: step wait-rebased: pass
rhiza: step rebased-green: entered, visit 1
PR #317 at 932a218: 1 check passed
rhiza: step rebased-green: pass
rhiza: step merge: entered, visit 1
Merged PR #317 at 932a218 as 20b567b.
rhiza: step merge: pass
rhiza: step close-out: entered, visit 1
Removed worktree /home/rhiza/code/rhiza.fix-the-daemon-never-reaps-its.
Rex tab window:01a1ae3e-d07c-71b5-8098-bc21520cdc52 was already closed.
Rex tab window:01a1ae40-d854-71e9-aec5-4d6c8f380214 was already closed.
Rex tab window:01a1ae42-41da-78a5-a192-15f50d403a7f was already closed.
Rex tab window:01a1ae43-4e76-7a99-a1a5-153055ebb453 was already closed.
Rex tab window:01a1ae44-583e-7d3f-af33-b667da5db437 was already closed.
Rex tab window:01a1ae45-6411-7c4e-94fc-ae011f56d45f was already closed.
Rex tab window:01a1ae46-e50f-7059-815c-c352a7a1772d was already closed.
Rex tab window:01a1ae47-ece0-7375-a9af-d7c9c2551099 was already closed.
Rex tab window:01a1ae48-805e-7114-b3ea-78a415175c9f was already closed.
Rex tab window:01a1ae49-88b9-77cb-b556-cfb2b23f28a2 was already closed.
Rex tab window:01a1ae4a-9dcc-77f3-a220-d890a258d103 was already closed.
Deleted branch cs/fix-the-daemon-never-reaps-its.
Deleted origin/cs/fix-the-daemon-never-reaps-its.
Updated main in /home/rhiza/code/rhiza.
rhiza: step close-out: pass
rhiza: run 01M6Q3WZMCZQ0ZGJ1S3F102Z7K succeeded
Run 01M6Q3WZMCZQ0ZGJ1S3F102Z7K succeeded

- Workflow: plan
- Change set: 01M6Q3X16PDW20R7N57BJ5JK6G: Fix The daemon never reaps its
- Worktree: /home/rhiza/code/rhiza.fix-the-daemon-never-reaps-its
- Autonomous: yes
- Started: 2026-11-06T00:25:01Z

## Steps

- interview (visit 1): pass, then milestone-check, session ab537112-dbb7-4d84-807c-01a1ae3eb5c1: said done and until held
- milestone-check (visit 1): pass, then review: exit 0
- review (visit 1): pass, then critic, session 91e1284e-ab1b-4d13-8c9b-01a1ae423069: said done and until held
- critic (visit 1): pass, then check, session 7ada030f-3bae-4ecf-b07d-01a1ae433c0a: said done and until held
- check (visit 1): fail, then revise: exit 1
    rhiza: run review-check: review round 1 of run 01M6Q3WZMCZQ0ZGJ1S3F102Z7K has 1 confirmed finding(s); revise the plan and review it again:
    - f1 contradiction on reap-own-session-children: The decision and daemon-reaps-drivers say the reaper never touches the git, make or hook children os/exec waits on, on the grounds that only detached drivers lead their own session. That holds only for children that do not call setsid themselves. A hook or other command the daemon runs through os/exec is not a process-group leader (no Setpgid), so a command like `setsid foo` calls setsid() in place, without forking, and the daemon's direct child becomes a session leader. The reaper would then wait4 it and the os/exec Wait would fail with 'no child processes': the race the decision set out to avoid. Either narrow the test (for example also match /proc/<pid>/cmdline to a 'run start|resume --foreground' driver, or record detached driver pids on disk so a re-exec'd image knows them), or state the limit and drop the 'never' claim. — confirmed: internal/api/daemon_hook.go:85 runs the owner's notify/event hook as exec.CommandContext(sh -c command) with no SysProcAttr, so the child shares the daemon's process group and is not a group leader. For a hook like 'setsid foo' (the code's WaitDelay comment already expects hooks that leave children behind), sh execs the single command and setsid(1) calls setsid() in place without forking, so the daemon's direct child leads its own session. The planned reaper (ppid == daemon, getsid(pid) == pid) would then wait4 it, and cmd.Run would fail with 'no child processes'. The decision's claim that os/exec hook children are 'never touched' is therefore false; it needs a narrower test (e.g. a recorded driver pid file or a check that cmdline is a run start/resume --foreground driver) or a stated limit.
    next: rhiza run status 01M6Q3WZMCZQ0ZGJ1S3F102Z7K
- revise (visit 1): pass, then review, session 9996860e-d0f9-4549-8bfc-01a1ae444584: said done and until held
- review (visit 2): pass, then critic, session 82b824b1-af5e-44ba-ba4b-01a1ae45504f: said done and until held
- critic (visit 2): pass, then check, session 34150438-e9e1-41f5-ac59-01a1ae46cfd7: said done and until held
- check (visit 2): fail, then revise: exit 1
    rhiza: run review-check: review round 2 of run 01M6Q3WZMCZQ0ZGJ1S3F102Z7K has 1 confirmed finding(s); revise the plan and review it again:
    - f1 contradiction on daemon-reaper-plan: The Source's summary still says 'The arbiter decided the daemon reaps only its own children that lead their own session (detached drivers), at start and on a timer, by pid, on Linux via /proc.' After round 1 (f1) the decision reap-own-session-children was revised to the opposite: it explicitly does not pick drivers by session leadership and instead waits only on pids recorded on a driver list under the git common dir. The Source, which the decision is derived-from, now misstates what was decided; its summary should describe the recorded driver list (and mention the round-1 revision) rather than session leadership. — confirmed: daemon-reaper-plan's summary says the arbiter decided the daemon reaps 'only its own children that lead their own session (detached drivers)', while reap-own-session-children, which is derived-from that Source as its only provenance, now states it 'does not pick drivers by session leadership' and waits only on pids recorded on a driver list under the git common dir. The Source is the decision's provenance yet backs a different statement, so a reader following `rhiza why` gets the rejected design. The fix is to amend the summary to record the round-1 revision (recorded driver list), keeping the original ruling as history.
    next: rhiza run status 01M6Q3WZMCZQ0ZGJ1S3F102Z7K
- revise (visit 2): pass, then review, session 740b2cd2-8ecb-406b-9466-01a1ae47db4e: said done and until held
- review (visit 3): pass, then critic, session f817525d-a705-4106-83c6-01a1ae486ee9: said done and until held
- critic (visit 3): pass, then check, session 01a44212-9116-46e8-ab90-01a1ae4976d9: said done and until held
- check (visit 3): pass, then gate: exit 0
- gate (visit 1): pass, then open-pr: exit 0
- open-pr (visit 1): pass, then wait-pr: exit 0
- wait-pr (visit 1): pass, then pr-green: held after 36 checks
- pr-green (visit 1): pass, then rebase: exit 0
- rebase (visit 1): pass, then wait-rebased: exit 0
- wait-rebased (visit 1): pass, then rebased-green: held after 30 checks
- rebased-green (visit 1): pass, then merge: exit 0
- merge (visit 1): pass, then close-out: exit 0
- close-out (visit 1): pass, then end: exit 0

## Accepted in the owner's place

- 2026-11-06T00:38:56Z accepted change set 01M6Q3X16PDW20R7N57BJ5JK6G (log entry 01M6Q4PP6FKBJ85PCF2RNNM6YF)

## Questions put to the arbiter

- question-ab537112-1 (01M6Q41DABCQW2A1P9TRH1Y2E6): How should the daemon reap its finished run drivers? (Fix The daemon never reaps its, 01M6Q3X1.) The intent proposes a periodic wait4(-1, WNOHANG), but the daemon also runs git, make and hook commands through os/exec, some concurrently from web UI request goroutines; wait4(-1) can reap one of those first, so its cmd.Wait/Output fails with 'no child processes'. Detached drivers are the only children started with Setsid, so they lead their own session. — decision reap-own-session-children
- review-01m6q3wz-r3-f1 (01M6Q4N00EHQZ53Z49E4AGMB9J): Plan review round 3 left finding f1 (contradiction on reap-own-session-children): The decision says the only limit left is pid reuse in the instant between a goroutine's Wait and dropping the pid, and that os/exec children (git, make, hooks) are never on the list. But the list lives under the git common dir and outlives not only a re-exec but a full daemon restart (stop/start, crash, systemd restart) with a new pid. Drivers of the old daemon are then reparented and reaped by init, yet their pids stay on the list; the new daemon only drops an entry once it scans it and sees ppid != its own pid. If any listed pid has meanwhile been reused by a git/make/hook child of the new daemon (ppid == new daemon), the reaper's wait4(pid, WNOHANG) can reap it and that cmd.Wait fails with 'no child processes': the very race the decision rules out. 'Runs once when the daemon starts' does not say it runs before the daemon starts any child, so the startup scan does not close it. Fix: record the daemon's pid with each entry (a re-exec keeps the pid) and reap only entries recorded by the running pid, dropping the rest; or clear the list on a fresh (non-re-exec) start before any child is started; and cover the stale-entry case in the leaf's test. The critic confirmed it: reap-own-session-children keeps the driver list under the git common dir and drops an entry only when a scan finds its ppid is not the daemon's pid. A fresh daemon start (crash, stop/start; internal/daemon/lock.go lets a new holder take over with a new pid, unlike reexec_unix.go's same-pid syscall.Exec) leaves the old daemon's driver pids on the list after init reaps them. Neither the decision nor the daemon-reaps-drivers leaf says the startup scan runs before the daemon starts any child, and the timer scan does not care which image wrote an entry. So a git/make/hook child of the new daemon that draws a stale listed pid gets ppid == daemon and is reaped by wait4(pid, WNOHANG), and its cmd.Wait fails with ECHILD. That contradicts the decision's claim that the only limit left is the Wait-to-drop instant, and the leaf's acceptance check does not cover stale entries. Fix: tag each entry with the recording daemon's pid (a re-exec keeps it) and reap only entries matching the running pid, or clear the list on a non-re-exec start before any child starts; add the stale-entry case to the test. How should it be settled? — decision reap-only-own-image-entries, not yet delivered

## Review rounds

- Round 1: 1 finding, 1 confirmed
  - f1 contradiction on reap-own-session-children: The decision and daemon-reaps-drivers say the reaper never touches the git, make or hook children os/exec waits on, on the grounds that only detached drivers lead their own session. That holds only for children that do not call setsid themselves. A hook or other command the daemon runs through os/exec is not a process-group leader (no Setpgid), so a command like `setsid foo` calls setsid() in place, without forking, and the daemon's direct child becomes a session leader. The reaper would then wait4 it and the os/exec Wait would fail with 'no child processes': the race the decision set out to avoid. Either narrow the test (for example also match /proc/<pid>/cmdline to a 'run start|resume --foreground' driver, or record detached driver pids on disk so a re-exec'd image knows them), or state the limit and drop the 'never' claim. — confirmed: internal/api/daemon_hook.go:85 runs the owner's notify/event hook as exec.CommandContext(sh -c command) with no SysProcAttr, so the child shares the daemon's process group and is not a group leader. For a hook like 'setsid foo' (the code's WaitDelay comment already expects hooks that leave children behind), sh execs the single command and setsid(1) calls setsid() in place without forking, so the daemon's direct child leads its own session. The planned reaper (ppid == daemon, getsid(pid) == pid) would then wait4 it, and cmd.Run would fail with 'no child processes'. The decision's claim that os/exec hook children are 'never touched' is therefore false; it needs a narrower test (e.g. a recorded driver pid file or a check that cmdline is a run start/resume --foreground driver) or a stated limit.
- Round 2: 1 finding, 1 confirmed
  - f1 contradiction on daemon-reaper-plan: The Source's summary still says 'The arbiter decided the daemon reaps only its own children that lead their own session (detached drivers), at start and on a timer, by pid, on Linux via /proc.' After round 1 (f1) the decision reap-own-session-children was revised to the opposite: it explicitly does not pick drivers by session leadership and instead waits only on pids recorded on a driver list under the git common dir. The Source, which the decision is derived-from, now misstates what was decided; its summary should describe the recorded driver list (and mention the round-1 revision) rather than session leadership. — confirmed: daemon-reaper-plan's summary says the arbiter decided the daemon reaps 'only its own children that lead their own session (detached drivers)', while reap-own-session-children, which is derived-from that Source as its only provenance, now states it 'does not pick drivers by session leadership' and waits only on pids recorded on a driver list under the git common dir. The Source is the decision's provenance yet backs a different statement, so a reader following `rhiza why` gets the rejected design. The fix is to amend the summary to record the round-1 revision (recorded driver list), keeping the original ruling as history.
- Round 3: 1 finding, 1 confirmed
  - f1 contradiction on reap-own-session-children: The decision says the only limit left is pid reuse in the instant between a goroutine's Wait and dropping the pid, and that os/exec children (git, make, hooks) are never on the list. But the list lives under the git common dir and outlives not only a re-exec but a full daemon restart (stop/start, crash, systemd restart) with a new pid. Drivers of the old daemon are then reparented and reaped by init, yet their pids stay on the list; the new daemon only drops an entry once it scans it and sees ppid != its own pid. If any listed pid has meanwhile been reused by a git/make/hook child of the new daemon (ppid == new daemon), the reaper's wait4(pid, WNOHANG) can reap it and that cmd.Wait fails with 'no child processes': the very race the decision rules out. 'Runs once when the daemon starts' does not say it runs before the daemon starts any child, so the startup scan does not close it. Fix: record the daemon's pid with each entry (a re-exec keeps the pid) and reap only entries recorded by the running pid, dropping the rest; or clear the list on a fresh (non-re-exec) start before any child is started; and cover the stale-entry case in the leaf's test. — confirmed: reap-own-session-children keeps the driver list under the git common dir and drops an entry only when a scan finds its ppid is not the daemon's pid. A fresh daemon start (crash, stop/start; internal/daemon/lock.go lets a new holder take over with a new pid, unlike reexec_unix.go's same-pid syscall.Exec) leaves the old daemon's driver pids on the list after init reaps them. Neither the decision nor the daemon-reaps-drivers leaf says the startup scan runs before the daemon starts any child, and the timer scan does not care which image wrote an entry. So a git/make/hook child of the new daemon that draws a stale listed pid gets ppid == daemon and is reaped by wait4(pid, WNOHANG), and its cmd.Wait fails with ECHILD. That contradicts the decision's claim that the only limit left is the Wait-to-drop instant, and the leaf's acceptance check does not cover stale entries. Fix: tag each entry with the recording daemon's pid (a re-exec keeps it) and reap only entries matching the running pid, or clear the list on a non-re-exec start before any child starts; add the stale-entry case to the test.

## Sessions

- interview, session ab537112-dbb7-4d84-807c-01a1ae3eb5c1: tokens input 44, output 8348, cache creation 49180, cache read 1324581; helper tokens input 0, output 0, cache creation 0, cache read 0
- arbiter, session fb744ab1-fa14-4d30-8b4d-01a1ae40c5d6: tokens input 12, output 3187, cache creation 25072, cache read 279878; helper tokens input 0, output 0, cache creation 0, cache read 0
- review, session 91e1284e-ab1b-4d13-8c9b-01a1ae423069: tokens input 18, output 3563, cache creation 30249, cache read 453210; helper tokens input 0, output 0, cache creation 0, cache read 0
- critic, session 7ada030f-3bae-4ecf-b07d-01a1ae433c0a: tokens input 14, output 2303, cache creation 29654, cache read 343691; helper tokens input 0, output 0, cache creation 0, cache read 0
- revise, session 9996860e-d0f9-4549-8bfc-01a1ae444584: tokens input 20, output 4098, cache creation 38806, cache read 550035; helper tokens input 0, output 0, cache creation 0, cache read 0
- review, session 82b824b1-af5e-44ba-ba4b-01a1ae45504f: tokens input 24, output 5378, cache creation 33895, cache read 640914; helper tokens input 0, output 0, cache creation 0, cache read 0
- critic, session 34150438-e9e1-41f5-ac59-01a1ae46cfd7: tokens input 10, output 1379, cache creation 26969, cache read 231225; helper tokens input 0, output 0, cache creation 0, cache read 0
- revise, session 740b2cd2-8ecb-406b-9466-01a1ae47db4e: tokens input 16, output 1543, cache creation 27394, cache read 393107; helper tokens input 0, output 0, cache creation 0, cache read 0
- review, session f817525d-a705-4106-83c6-01a1ae486ee9: tokens input 16, output 3976, cache creation 30941, cache read 398418; helper tokens input 0, output 0, cache creation 0, cache read 0
- critic, session 01a44212-9116-46e8-ab90-01a1ae4976d9: tokens input 14, output 2502, cache creation 30600, cache read 344803; helper tokens input 0, output 0, cache creation 0, cache read 0
- arbiter, session 0f7b61b5-9f43-4fd6-bb7e-01a1ae4a8bb2: tokens input 10, output 2230, cache creation 30382, cache read 238173; helper tokens input 0, output 0, cache creation 0, cache read 0

Totals: tokens input 198, output 38507, cache creation 353142, cache read 5198035; helper tokens input 0, output 0, cache creation 0, cache read 0