New `find_runaway_subactors()` helper + autouse
`_detect_runaway_subactors_per_test` fixture that
samples `psutil.cpu_percent()` on descendants to
catch tight-loop bugs (e.g. #452-class `recvfrom`
on a closed socket). Checks both at setup
(leftovers from a prior hung test) and teardown
(spawned by this test).
Intentionally does NOT kill the runaway — emits
a loud warning with diag commands (`strace`,
`lsof`, `ss`, `kill`) so the pid stays alive for
hands-on investigation. Session-end reaper still
SIGINT/SIGKILL survivors on normal exit.
(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
(cherry picked from commit 5cf0312c78)
Gud Boi
a4f6d893ed