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.
Confirmed and fixed, each with a regression test that failed first:
- Concurrent writes to different namespaces lost whole sections on disk
(each persist rendered the full document from a stale text): the local
provider serializes render->write->rename->text-commit on one internal
persist chain shared by every namespace queue.
- One throwing settings/updated listener starved the rest (cordis emit
stops at the first throw): commit fans out per listener via
events.dispatch, contains individual failures, and rethrows the first
INVARIANT-coded error only after every listener ran.
- Write queues ignored fiber/service lifecycle: the base init now
registers a teardown that refuses new writes and drains queued chains;
queued tasks re-verify service liveness and namespace ownership before
running and again before committing, so a registrant disposed
mid-flight is never notified and a disposed service never commits.
- Async watcher invocations could interleave (a slow stale call applied
last): each watcher carries a serialized invocation chain — one call
at a time, in commit order; JSDoc/doc pages state the async timing.
- update/replace borrowed the caller's object until the queued task ran:
inputs are structured-clone snapshotted at call time; non-cloneable
plain objects reject with a typed error.
- Composition guard now proves the documented fallback: the consumer
uses the optional scoped-inject shape and boots both with the settings
entry (hot publish) and without it (entry-config resolution, no scope).
- core-data-structures index: settings.md row added to the sub-page
table in core.md/core.zh.md.
Both packages hold per-file 100% coverage across repeated runs.
Confirmed and fixed, each with a regression test that failed first:
- Concurrent update() lost patches (merge over one stale snapshot):
per-namespace serialized write queues; a failed write cannot poison
the queue for later writers.
- Fixed-name .tmp write followed planted symlinks and kept stale modes:
random-suffix sibling, exclusive-create (wx), 0600, cleanup on
failure, then rename.
- A throwing settings/updated listener escaped commit and permanently
wedged the provider reload chain (rejected refreshTask): commit now
contains listener failures (INVARIANT-coded errors still propagate),
async watcher rejections are adopted and contained
(watch callbacks are officially void | Promise<void>), and the
provider chains refreshes on a settled tail with an error log.
- No way to remove a user override: scope/service replace(section)
sets the user section wholesale; replace({}) re-inherits base and
schema defaults.
- The three-primitive provider contract did not hold (base never
called load()): the base Service.init loads and publishes once;
settings-local delegates via yield* super[Service.init]().
- Dispose did not quiesce: teardown flags closed, closes the watcher,
then awaits queued/in-flight reloads; closed is re-checked across
await points.
- Invariant now checks the authoritative relation with the seam's own
deepEqualJson: emitted next must equal settings.get(ns), and
next/prev must differ structurally (cosmokit dependency dropped).
- New docs/core-data-structures/settings.{md,zh.md} with type-equiv
blocks + manifest entries; catalog types moved from exemptions to
LINK_MAP; website page registered.
Both packages stay at per-file 100% coverage.
Two-package capability family mirroring session-persistence/:
- dsh-settings: abstract Settings service — namespace registry with
caller-fiber effect registrations, layered resolution (schema defaults
< composition base < user document), schemastery validation,
per-namespace deep-equal commit detection, and the settings/updated
event. Boot/registration validation fails loud; provider publishes
keep last-good per namespace.
- dsh-settings-local: settings.yaml/.json provider — resolveSpec
defaulting to $DSH_HOME/settings.yaml, chokidar hot reload,
content-equality self-write suppression, atomic 0600 tmp+rename
writes, comment-preserving YAML namespace patching.
Consumers register inside ctx.inject(['settings'], …), so every
composition works unchanged without a mounted provider. Real Loader +
Include composition test proves cordis.yml boot and external-edit hot
propagation; HMR disposal test proves registry cleanup. Both packages
hold per-file 100% coverage.
Doc budgets rise 1705→1710 (AGENTS.md) and 835→845 (packages/README.md):
one structural line per file for the new package group.
Agent Note: .agents/notes/implemented/architecture/2026-07-28-user-settings-seam.md
Tianyi Cui
Yichen Jiang