Review round three found the provider's write path could destroy state it
never observed:
- Watcher reloads and document writes ran on two independent promise
chains, and a write rendered the whole next document from the cached
text. An external edit still inside the debounce window (or missed
outright) was overwritten, and the follow-up reload no-oped because the
post-rename content matched the cache — the edit vanished without a
trace. Reloads and writes now share one operation chain, and every write
starts by reconciling the on-disk text into the seam before rendering,
so unobserved sibling sections survive and publish first. An unparsable
on-disk document fails the write loud instead of being overwritten.
- The initial load raced the watcher's own setup: a change written between
that read and the watcher becoming active never fired an event. The
watcher's ready signal now queues one reconcile, closing the gap.
- Two processes sharing a harness home rendered from independent caches,
last writer winning. Writes now hold a wx-created <file>.lock sibling
around the read-render-rename cycle with bounded backoff, a crashed-
holder stale takeover, and a deadline failure; readers stay lock-free
because the rename commit is atomic.
- renderYaml replaced the whole namespace node, dropping every comment
inside the section. The next section now lands as a leaf-level diff
(set changed values, delete removed keys), so comments, anchors, and
formatting survive on every untouched node and on the key of every
changed pair; arrays still replace wholesale when unequal.
Review round three found four seam defects:
- A watch() disposer only removed the observer from the set; an invocation
already chained onto the watcher tail still ran after disposal. Watchers
now carry an active flag checked when a queued invocation would start,
and the service dispose drain awaits started invocations (pendingTails)
beside the write queues, so disposal is quiescent.
- The settings/updated manual fan-out caught only synchronous throws; an
async listener rejection escaped as an unhandled rejection. Thenable
returns are now contained through the shared listener diagnostic, and
the event contract documents that the INVARIANT rethrow serves
synchronous listeners only.
- structuredClone admitted Dates, Maps, BigInts, and cycles that YAML/JSON
storage silently distorts on reload (a Date lands as a timestamp string,
a Map as a plain map, a BigInt as a number). The write snapshot is now a
single-pass cloneJsonShaped walk that rejects non-JSON values with their
path before anything persists.
- mergeLayers' per-entry undefined guard became dead code once the clone
strips undefined entries at the boundary; removed, with the sparse-patch
contract restated at its enforcement point.
`isInheritedSeq` had no production caller — only its own tests — so it was
a public core export shaped by nothing. A bracket owner reads the boundary
positionally; the helper belongs with the compaction seam, where a real
consumer decides its signature.
Also condense the `session/inherited` and `lastActivityTime` docs.
A plugin owning a standalone open/close bracket cannot tell a dead marker
from a live one: an unmatched `compact/start` reads identically whether the
previous writer died mid-compaction or a compaction is running now.
`Session.firstLiveSeq` already holds that answer exactly, but only in memory.
Append the log-only `session/inherited` event at that seq from the seeded
constructor — the single waist all six seeded-start paths pass through
(resume, configured startup on a persisted id, `sessions.fork()`, a subagent
fork child, `adopt()`'s live prefix, and a bare seeded `create`). Read it
through the new `isInheritedSeq(events, seq)`.
The constructor placement means persistence needs no changes: the marker is
already in `events` when a backend captures the creation seed, so it rides
the ordinary seed path with no load-time write. It also covers fork, where
the inherited bracket's owner may still be running — the case a
persistence-layer boundary could not reach.
Activity ordering excludes the boundary through `lastActivityTime()`, since
lazy resume makes browsing a pickup and the three call sites would otherwise
float every opened session to the top of a picker or list.
The seat's height publisher needs a ResizeObserver stub in every spec that
renders ConversationRoot (jsdom has none), and the two branch-tail StatsLine
assertions move to the grouped detail-row output.
Stats line moves into the InputBar's new footer slot (sharing the card's
width column) and expands to the design's grouped detail row: turns/steps,
LLM and tool wall time, cache hit, and input/output token split, all
derived client-side from the snapshot. The composer stack owns one 8px
rhythm, the seat fades the transcript through a fixed 36px gradient band,
back-to-bottom follows a live --dsh-composer-height, and goal/todo strips
share one 752px tip-fill column.
Conflict: apps/web/tests/workspace-flow.snapshot.ts was deleted on
master (#921 sinks assembled-app journeys to package-level benches)
and modified here (show-hidden/prefix-filter and crumb-back lanes).
Resolved by taking the deletion: the same behaviors are asserted at
package level in directory-picker-browse's directory-browser.spec.tsx
and client-flow.spec.tsx, which is the post-migration home for them.
