Emit read the whole artifact into memory and erf.Read then allocated a
second full copy of every payload, so a hak cost about 5x its size in
RAM. The 7 GB runner was OOM-killed on any hak over ~1.4 GB, which
blocks the NWSync backfill and every release that rebuilds a large hak.
Emit now opens the artifact, hashes it by streaming for the key check,
parses only the header and resource table via erf.ReadIndex, and reads,
hashes, compresses and stores one payload at a time. erf.Read keeps its
old shape but returns payloads as subslices instead of fresh copies,
which removes the second copy for the other callers too.
The zstd encoder pool also held one window-sized history per CPU — about
200 MB of live heap on a 24-core runner. EncodeAll is single-threaded
per call, so concurrency 1 gives byte-identical blobs for far less
memory.
Peak heap is now flat at ~22 MB for both an 8 MB and a 64 MB hak, and a
regression test asserts it does not scale with artifact size.
Closes#76
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Builds sow-tools#53. Format spec followed is the resolution comment of sow-platform#94, checked line by line against niv/neverwinter.nim at HEAD (`nwsync.nim`, `compressedbuf.nim`, `nwsync/private/libupdate.nim`).
## What lands
`crucible nwsync emit <artifact> --out DIR` — explodes one `.hak`/`.erf`, or one loose file such as the TLK, into NWSync blobs plus a NSYM v3 manifest covering only that artifact, with the same `.json` sidecar upstream writes. Blob path `data/sha1/<h0h1>/<h2h3>/<sha1>`, body in NWCompressedBuffer framing (magic `NSYC`, version 3, algorithm 2, uncompressed size, zstd header version 1, dictionary 0, raw zstd frame). The sha1 that names a blob is over the uncompressed bytes.
`crucible nwsync assemble --order NAMES --entries DIR --out DIR [--group-id N]` — merges the per-artifact manifests into one, reading no bulk data at all. Merge rule is resref shadowing, not concatenation: a resref in more than one artifact resolves to the earliest artifact in `--order`, which is how the game resolves it. `--group-id` stays caller-supplied (1 current, 2 testing; 0 is absent, matching upstream omitting a zero integer meta field).
Rules taken from upstream and not re-invented: `nss`/`ndb`/`gic` always skipped; an unresolvable restype is a hard error, not a skip; a resource over 15 MB fails closed; no `latest` file and no `.origin` file, ever. A `.mod` is refused outright — a persistent world publishes no module contents, so the module contributes no bytes.
## Two deliberate departures
- **Emitter version is its own field, not the build revision.** `emitter_version` is a constant bumped only when emitted bytes change. Keying the refuse-to-merge check on `created_with` would invalidate every published index on every unrelated crucible commit and force a re-emit of the whole 15 GB corpus — the opposite of "nothing downstream ever needs the hak again".
- **`SOURCE_DATE_EPOCH` pins the sidecar timestamp.** The manifest itself was already deterministic; the sidecar's `created` was not, against the determinism rule in `docs/consumer-contract.md`.
## Not in this PR, and why
- **Direct upload.** Only the local `--out` sink exists, which is the conformance path. The upload sink and the mid-hak-failure question are sow-tools#60, and the consumer wiring is #65.
- **The conformance run against upstream.** sow-tools#59 owns getting `nwn_nwsync_write` running and capturing reference output. The format here was read from upstream source rather than from its output, so the byte-for-byte manifest comparison and the after-decompression blob comparison still have to happen — that is what #59 is for. The tests in this PR check the layout against the spec, so a shared misreading would pass them.
- **The `artifacts/haks/sha256/<a>/<b>/<sha256>.nsym` location.** emit writes `<out>/<name>.nsym`; where a publisher puts it is the publisher's business (#65).
- **The acceptance gate** — a real client syncing from an assembled manifest — is unchanged and still open.
## Checks
`make check` green (vet, unit tests, shellcheck, yamllint, workflow contract), `make smoke` green with the new builder, `nix build .#crucible` produces `crucible-nwsync`.
🤖 Generated with [Claude Code](https://claude.com/claude-code)Reviewed-on: #71
Co-authored-by: vickydotbat <vickydotbat@tutamail.com>
archvillainetteandClaude Opus 5