The four CCCI state files (deploys countfile, opstate, deps, depskip) were keyed
by app domain in shared /tmp. A second run of the same domain executes its main()
preamble + deploy_app's pre-lock _record_deploy BEFORE blocking at the app lock,
so it reset/polluted the live first run's counter (false DG4.1 deploy-count=2,
build 279) and the first run's end-of-run os.remove crashed the second
(FileNotFoundError, build 281). Masked pre-restructure by the end-to-end recipe
flock. Now keyed by run id + harness pid via _run_state_path(); children receive
exact paths via the CCCI_*_FILE env vars, so domain keying was never load-bearing.
tests/concurrency/test_run_state.py: path-invariant cases + a real-process
regression (helpers.py deploy-count-run) reproducing the live interleaving —
verified to FAIL under simulated shared keying. docs/concurrency.md §3 updated.
Rewritten to the restructured model: lifetime-hardening guards (PDEATHSIG/SIGTERM/SIGALRM +
setsid/trap), per-run ABRA_DIR isolation (same-recipe runs now parallel), per-app-domain flock
(double-!testme serialisation), flock-probe janitor decision table (incl. the inode-identity
race rows), updated failure-mode table (cancel now tears down via the harness's own funnel;
reboot reaps immediately; 60-min deadline bounds everything), single-knob config table, how to
run tests/concurrency, fresh file/symbol index + deleted-symbol list for grep verification.
Also drops the last stale concurrency.limit mention from the .drone.yml header comment.
