The activation-capability probe spawns the whole Node CLI rather than
exec'ing a binary. Measured 3.0-3.7s on an idle 4-core VM and 3.55-3.61s
on web1, against `node -e 0` at 0.05s. The budget was 2.0s, so the probe
timed out on every call on both hosts.
The gate is fail-closed, and an expiry is indistinguishable from "no
capability", so every fleet seat launch was denied with a version-skew
message telling the operator to "upgrade both as one unit" -- advice that
cannot fix a timeout. This is why web1 shows roster seats with no live
sessions.
Raise the budget to 20s, well clear of the measured range, and add
MOSAIC_LEASE_VERSION_PROBE_TIMEOUT_SECONDS for slower hosts. Unusable
override values fall back to the default rather than removing the bound.
Also fix _resolve_probe_command ignoring the environ it is handed:
shutil.which was called without path=, so it read the ambient PATH. That
made test_returns_none_when_mosaic_is_not_resolvable_on_path pass only
because the 2.0s budget expired first -- right answer, wrong reason, and
it masked the timeout defect. The suite's runtime drops from 2.0s to
0.002s, which is that accidental timeout leaving.
Verified: 18/18 version_coupling_unittest (new tests red against the old
gate: 2 failures + 1 error), tsc build clean, test-start-agent-session.sh
and test-fleet-units.sh rc=0. invariant_r_unittest fails identically with
and without this change (pinned pi 0.84.1 vs installed 0.84.2).
Jason Woltje
9efd903c16