Integrates the merged and frozen Wave 3 lab commit
b1666951faf8285054e1ca90f11533b0fb53fb57 with a normal merge, preserving
every Wave 4 commit unchanged.
Conflict: src/agent_runtime/resources.py. Wave 3's _control_plane_snapshot()
/ _control_plane_path(path, *, snapshot=None) split is kept. The snapshot adds
the effect-store directories to its prefix set after the recursive job-dir
inventory and no longer references path (the auto-merged prefix check would
have raised NameError there). _control_plane_path calls _aliases_effect_store
after its os.stat, only for multiply linked files, so single-link files never
list the store.
Semantic reconciliation (no textual conflict): bg_monitor keeps launch
settlement right after the first successful validate_job and before the
authority check, with Wave 3's post-drain revalidation intact. The
deleted-session branch, terminal before linkage validation, now settles a
validated launch too: that job is later pruned and its publication retired,
which would otherwise leave its effect RUNNING. Regression tests cover the
snapshot form of the effect-store check and both deleted-session linkage
outcomes.
A hardlink into the effect store was protected only by the log's own nlink
refusal, which an agent could undo by removing the alias after writing
through it. Adding the store to the recursive control-plane inventory would
make every path check cost grow with accumulated runs. _aliases_effect_store
instead uses the store's invariants: logs and launch indexes refuse
st_nlink != 1 and the store is flat, so only a multiply linked regular file
on the store's device is compared by inode against one non-recursive listing.
Single-link files cost nothing and the store is never rglob-inventoried. The
helper takes a stat result so it plugs into Wave 3's scan-local snapshot after
the rebase.
Claims are fsynced to a per-lineage JSONL log before a caller may invoke a
backend; a persistence failure raises EffectPersistenceError (a
ResourceIdentityError) so dispatch fails closed. Outcomes and observations are
appended; nothing is rewritten. Reload validates every record strictly, ignores
only a torn final write, and fails closed on corruption, forgery or hardlink
aliasing. recover_interrupted appends INTERRUPTED/possible-impact outcomes for
claims that never settled and leaves RUNNING background effects alone.
The effect store is added to Wave 3 control-plane paths (prefix check only;
the log itself refuses aliased files), so filesystem tools cannot forge it.
Tests redirect the store to a session tmp directory.
Alexandre Teixeira