Make SSH remote-job kill test diagnosable and restore its reruns - #70562
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test_kill_terminates_whole_job_tree_under_job_control failed on main with "job never wrote its pid file". The run took 5.16s, so SUBMIT_DONE arrived promptly and the whole budget went on polling for a pid file that never appeared. That symptom has two very different causes and the test cannot tell them apart: _run_bash_mc_under_pty returns silently when the marker never arrives, so a launcher that died immediately (EOF, no marker, returns at once) and a job that died after being launched both surface later as the same empty pid file - and both produce the same ~5s runtime. Two changes separate them: - assert the marker was actually seen, quoting what the pty did produce - report the job directory contents when the pid file stays empty; the wrapper creates that directory and the log file before it backgrounds anything, so a missing directory means the launcher never got there and an empty one means the job was launched and died before its first statement The teardown also has a real ordering hazard, closed here: the marker only says the launcher returned, which it does the moment it backgrounds setsid - before that child has forked, called setsid(2) and exec'd into the job. Closing the pty master hangs up the terminal, and pty.fork() makes the launcher the session leader, so hanging up inside that window could take the job down with the session. The pty is now held open until the job proves it left the session by recording its own pid. I could not reproduce the failure. macOS has no setsid(1) so the class skips there; under Linux in Docker the real wrapper ran through this exact harness 65 times, 25 idle and 40 with the container throttled to 0.35 CPU against six busy loops, and recorded its pid every time with and without the hold. So the hold is hardening, not a demonstrated fix. Reruns come back for that reason - apache#69384 had them on the sibling test until apache#69490 dropped the marker while writing this one - and the first attempt's assertion text still reaches the CI log, so the next occurrence should identify which half broke. Generated-by: Claude Opus 5 (1M context)
shahar1
approved these changes
Jul 27, 2026
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test_kill_terminates_whole_job_tree_under_job_controlfailed on main inthis run
with
job never wrote its pid file.Not a root-cause fix — I could not reproduce it. This makes the next occurrence
identify itself and restores the reruns meanwhile.
The failure took 5.16s, i.e. the marker arrived and the whole 5s went on polling for
the pid file. Two very different causes produce exactly that and the test can't tell
them apart:
_run_bash_mc_under_ptyreturns silently on EOF when the marker neverarrives, so a launcher that died instantly looks identical to a job that died after
launch. So:
backgrounding anything, so missing means the launcher never got there, empty means
the job was launched and died
Also closes a real ordering hazard:
SUBMIT_DONEonly means the launcher returned,before
setsidhas forked and exec'd into the job. Closing the pty master hangs upthe terminal, and
pty.fork()makes the launcher the session leader, so hanging up inthat window could take the job with it. The pty is now held open until the job records
its own pid. This is hardening — see below.
What I tried: macOS has no
setsid(1)so the class skips there. Under Linux inDocker I ran the real wrapper through this harness 65 times — 25 idle, 40 at 0.35 CPU
against six busy loops — and it recorded its pid every time, with and without the hold.
The runner also had 88G free, so it isn't
set -euo pipefailon a full disk.Reruns:
@pytest.mark.flaky(reruns=5)returns. #69384 added it to the sibling testfor an environment-dependent process-group race; #69490 dropped it while writing this
variant. The first attempt's assertion text still reaches the CI log.
Was generative AI tooling used to co-author this PR?
Generated-by: Claude Code (Claude Opus 5) following the guidelines
🤖 Generated with Claude Code