Range observation waited for an active transient scope to leave `active`
before it would prove the managed range empty. systemd ends a scope only when
it observes the populated-to-empty transition, so a payload killed before the
manager placed it in the scope's cgroup leaves the unit active with an empty
cgroup forever. `waitForExit()` then polled a unit that could not change, and
`LocalSubprocessRuntime.disposeManagedProcesses()` awaited it without bound —
teardown hung for any command cancelled immediately after spawn.
Each state query now also reads the unit's process count. Once termination was
requested and the launcher has exited, a still-active unit reporting no
processes is the empty range: the launcher forked every process it will ever
fork, so nothing later joins that cgroup. The owner stops the leftover unit so
transient units cannot accumulate, and an unreported or `[not set]` count
stays unknown and keeps waiting.
The race needs a live user-systemd manager, so it stayed dormant wherever the
native scope path was unavailable and surfaced once CI routed lanes onto the
Blacksmith hosted image, whose runners accept that path. Ten repetitions of
`local.spec.ts > disposal kills still-running processes and awaits their exit`
in a Linux container with a user manager failed seven times before the change
and passed ten times after it.
turtle1999