The batched ingest's append-failure catch had zero coverage, and two doc
statements overstated the loss: the Warning said the burst's values were
"dropped", and RecorderStatus.OutboxAppendFailures said "the value was
dropped, not recorded". The outbox contract is prefix-never-orphan, so a
partial-prefix failure leaves entries durably queued that drain normally.
- New test pins the branch: one 3-item burst whose group commit commits a
1-entry prefix then throws => OutboxAppendFailures == 1 (per burst, not
per value), TotalRecorded == 0, actor alive, and the prefix still reaches
the writer via the post-failure DrainTick (drainInterval 30s, so the
steady cadence cannot account for it). Falsified twice: counting per item
and dropping the drain nudge each turn it red.
- Second test pins the OperationCanceledException filter from its
observable side - a cancel that is NOT shutdown is metered, not swallowed.
Removing the 'when (_lifetime.IsCancellationRequested)' turns it red. The
shutdown side has no cheap seam (the counter dies with the actor).
- Docs corrected: OutboxAppendFailures counts FAILED BATCH APPENDS, one per
burst whatever its size (a granularity change from the per-value era), and
is not a count of values lost; TotalRecorded under-counts when a commit
fails after a partial prefix. Log message says "failed to append" and
names the prefix. No functional change beyond the message string.
Also folds in the DrainBatchSize default alignment behind 0298a0b9: the
recorder's two ctor defaults and its non-positive fallback still said 64
while ContinuousHistorizationOptions.DrainBatchSize now defaults to 1024.
No test pinned the old 64.
CLAUDE.md — a new "How a deploy reaches that address space" block under the v3
Batch 4 address-space section. The blanket ChangedRawTags/ChangedUnsReferenceVariables
=> Rebuild rule is gone, so the doc now names both halves explicitly: what still
rebuilds (alarm-bearing raw-tag deltas, raw-tag identity changes, raw container
renames/removals, changed equipment/alarms) and what is now surgical (non-alarm
attribute deltas, every UnsReferenceDelta). Also records the three semantics that
are easy to break by accident: mirror repair rides UnsReferenceVariable's inherited
backing fields (omitting a newly-inherited field silently reopens the staleness),
a degraded non-rebuild apply deliberately does not advance _lastApplied, and the
raw-realm announce gap is no longer neutral now that surgical adds keep
subscriptions alive.
CLAUDE.md ConfigSource — the RevisionHash == SHA-256(artifact bytes) paragraph is
still true and stays; it gains the clause that the blob is gzip-compressed since
2026-08-15 and the hash covers the COMPRESSED bytes, which is precisely why the
fetcher, cache and serve path were untouched.
docs/Uns.md + docs/Raw.md — one section each on what a deploy now tears down, from
the authoring surface's point of view, including the mirror repair semantics
(identity-preserving backing edits update in place and keep their MonitoredItems;
re-points and effective-name edits remove+recreate that one node).
docs/Configuration.md — "Artifact compression (2026-08-15)" under ConfigSource/
ConfigServe: gzip inside the hashed bytes, magic-sniffed on read, pre-upgrade
uncompressed rows still parse, plus the two operational facts an operator needs.
The first deploy after upgrade re-hashes every revision (same config, new bytes,
new RevisionHash) so it is a one-time full re-dispatch rather than a no-op; and
rollout is ordered — nodes must run artifact-sniffing code BEFORE central starts
emitting compressed blobs, since a pre-upgrade node handed a gzip artifact fails
the apply and keeps last-known-good until it is upgraded.
Plan doc — a "Follow-ups (recorded, not implemented)" section covering the seven
items surfaced during implementation and review: the raw-realm announce gap, the
RemoveEquipmentSubtree dangling-inverse-edge exposure, the missing end-to-end test
for a degraded remove-bearing apply's ratcheted rebuild, the scripted-alarm
thin-plan-ids-against-rich-rows blindness, the absent monotonic dispatch sequence,
LocalDb store ordering under concurrent StoreAsync, and threading the in-hand blob
through RestoreApplied.
tasks.json — all nine tasks completed.
Docs only; no source changes.
C1 — a non-rebuild apply reporting failedNodes > 0 no longer advances _lastApplied.
Pre-delta-materialisation the full passes re-ensured every node on every apply, which
silently repaired any prior swallowed sink fault. The delta path removed that accidental
self-healing: a failed node sat inside _lastApplied, never appeared in a diff set again,
and EnsureVariable early-returns on the ones that landed — so it was lost until an
unrelated change forced a rebuild. The advance also moved to AFTER the materialise
passes, so a throwing pass leaves _lastApplied at the previous composition too. A
rebuild still advances even with failures (the ratchet is its resync path).
I2 — a UnsReferenceDelta whose identity is unchanged (same NodeId, EquipmentId and
BackingRawPath) is now applied in place via UpdateTagAttributes(Uns) instead of
remove+recreate, so the mirror's MonitoredItems survive an operator historizing or
reshaping the raw tag behind them. Remove+recreate stays for identity-changing deltas
(re-point, effective-name edit).
I3 — RemoveVariableNode severs the inverse half of every outgoing Organizes edge, the
variable-node counterpart of UnwireAlarmNotifiers. Rebuilds used to sweep these up;
surgical applies made rebuilds rare, so they accumulated on the raw node for the life of
the process.
I5 — added UNS reference variables are announced (their equipment folder is the parent,
already the Uns realm). Raw adds still are not; the gap comment now says so honestly
rather than calling it neutral and pre-existing.
I4 + M1 — corrected two comments that no longer described the code: the "re-point →
rebuild" claim in ApplyPureRemove, and the "N lock acquisitions" rationale for the delta
passes (Ensure* early-return on a dictionary probe before the lock).
Joseph Doherty