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…call
Mirror initialization previously walked the document container by
container (~10 wasm crossings per container: id/kind/get/keys/toJSON).
buildRootStateSnapshot now reads the whole doc with a single
doc.getDeepValueWithID() call and builds state, $cid markers,
containerRegistry, inferOptionsByContainerId and rootPathById in one JS
walk that replicates registerChildContainer/containerToMirrorState
semantics exactly. No container handles are created during init; trees
and unhandled kinds fall back to the existing handle-based logic, and
the legacy traversal is kept as a fallback for loro-crdt versions
without getDeepValueWithID.
- Defensive cid parsing: tolerates both the Debug-like
"idx:N, id:cid:..." format and bare container ids.
- loro-crdt <1.15 drops the {value,cid} wrapper for empty containers,
making them indistinguishable from embedded plain values; the walk
disambiguates via the parent's cached getShallowValue() (one extra
call per affected parent only).
- Adds a seeded parity fuzz test (bulk vs legacy: state, $cid via
cidsEqual, registry, infer options) and a dependency-free benchmark
(pnpm bench:bulk-init, ~67k-container session-history-shaped doc):
wasm crossings during init drop from ~527k to 1.
This was referenced Sep 3, 2026
zxch3n
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Problem and behavior
Mirror initialization previously traversed document containers through many individual WASM calls. This PR builds state,
$cidmarkers, schema registrations, and inference options from onedoc.getDeepValueWithID()snapshot and a JS walk. Trees and unsupported shapes retain the handle-based fallback; versions without the deep-value API retain the legacy snapshot path.Container identity is verified against a cached parent shallow read before a child wrapper is interpreted. Embedded user objects such as
{ cid: "cid:root-other:Map", value: { message: "kept" }, extra: 123 }remain intact rather than being unwrapped. This also handles empty containers with omitted wrappers in loro-crdt 1.13.3. Old mergeable-reference binary markers use a targetedget()check to distinguish containers from user bytes.The deep-value CID parser supports Debug-format and bare IDs. Unknown-root normalization, Ignore fields, decoding, and incremental state behavior are retained.
Validation
Performance limitation
The correctness fix requires additional parent shallow reads; this is not a one-WASM-call initialization. The benchmark now reports these reads explicitly.
Same-process Node 22 / locked loro-crdt 1.13.3 comparison, 171 entries × 30 items (~67k containers), 3 warmups and 10 samples, explicit GC:
The corrected bulk path is slower in this measurement. The original speedup / projected 2× claim is not an acceptance result for the corrected code; performance needs further work before this PR should be merged as an optimization. Read counts above are instrumented methods, not every WASM crossing.
Published loro-crdt 1.16.0 follow-up
Updated core/react/jotai loro-crdt requirements and the lockfile to ^1.16.0 / 1.16.0. Build, 525 tests, lint (0 errors), and typecheck pass. A fresh default ~67k-container benchmark on the published package reports bulk p50 360.044 ms (1 deep read, 15,733 instrumented parent shallow reads). The older 1.13.3 comparison above remains historical; this change does not replace the standalone performance acceptance requirement. #98 now tests the published container-tree path.