Review fixes for SESSION-02. An expired caller deadline was becoming a failed epoch without the ipc-v1 section 6 resolution. That procedure existed and was correct and had exactly one caller, a test injection, so the deadline this slice introduced bypassed it and a merely slow participant lost its epoch. Deadlines is now the two-stage shape section 6 describes -- a probe, then a bounded resolve budget and attempt count -- call_owned returns a typed CallOutcome so an expiry is distinguishable from a refusal, and Prepare, Commit, Advance and the lifecycle calls all query the same request id against the same incarnation before the epoch can fail. This is also step-v1 section 7's Advance row, which was imperative about it. The coordinator peak-RSS column was measuring the measuring process. VmHWM never falls and every row shared one process, so the column was cumulative and the mode ranking reversed when the rows were reordered. Each row now runs in a measure-row child of its own. The corrected numbers say the opposite of what the first report claimed: the coordinator's own peak is roughly flat across the modes and lowest in process mode, and the cost of the split is the children. workers-v1 section 2 bounded Agent.Initialize's workerThreads by "within launcher allocation" and named no wire for it. Dated amendment: HelloResult.limits gains workerThreads, the worker reports what its launcher gave it, and the launcher refuses one that disagrees. The schema set, the shared fixtures and the TypeScript package move together; contractDigest changes, which ipc-v1 section 4 provides for. Also: the stale-epoch row now reaches the stale-epoch path against a live agent process and asserts exact codes on both halves; the router-restart row asserts the handle drop it claimed; frames are counted from the behaviour trace instead of calculated; the README says which suites run over which transports; bootstrap is fence-guarded; the shutdown reason is an Id rather than a silent fallback; and agent_mutations returns None rather than zero where the counter lives in another process. |
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@flybrain/session-types
The session framework contracts in TypeScript: types, validation, canonical JSON (RFC 8785) and canonical digests.
The other half of services/flysim/crates/fly-session-types.
Same rules, same canonical bytes, same digests, and the same fixture corpus: this package
loads the crate's fixtures/ directory rather than keeping a copy, so a case written once
holds both languages to it. Nothing here opens a socket; it reads, validates and hashes.
This is the internal session path (docs/design/session-framework/). The public feed and
control contracts are unchanged and still live in @flybrain/feed.
Modules
| Module | Contents |
|---|---|
canonical |
canonicalize, digestOf, parseStrict, requireEnvelopeFit, rejectBusIdentities |
scalar |
Id, U64, Digest, Scope, RationalNs with checked arithmetic, and the four identities as branded types |
reader |
Reader, which reads one object field by field and then refuses any field it did not read |
common |
readScope, readSchemaRef, readTypedValue, operationKeyDigest, bodyDigest |
media |
View and audio descriptors and refs, and the State.* payloads |
workers |
The closed enums and every Agent/Environment/Worker method payload |
rpc |
SessionRpcRequest, the success and failure replies, ErrorCode, MutationCertainty |
publishing |
SessionDescriptor, CommittedSnapshot |
trace |
The step-v1 section 8 record and the behaviour-only comparator |
seed |
seed-derivation-v1 |
checkpoint |
The FLYSESS1 envelope layout |
fixtures |
Loading the shared corpus |
Reading a payload
Every reader takes unknown, validates, and hands back a value whose fields are exactly the
ones it read. A payload with an unknown or misspelled field fails instead of silently
defaulting, and a round trip through a reader is the test that no field is dropped.
import { canonicalize, digestOf, readScope, readPrepareParams, bodyDigest } from '@flybrain/session-types';
const scope = readScope(payload.scope);
const params = readPrepareParams(payload.params);
const digest = bodyDigest('Agent.Prepare', scope, params); // the ipc-v1 section 5 comparison
Rules that need another value in hand are separate functions, because a payload cannot check
them alone: validatePortControlAgainst, validateBatch, validateSensoryInputAgainst,
validateObservationAgainst, validateStepResultAgainst, validateSnapshotAgainst,
validateTelemetryRoles, validateRemainder, validateCommitAgainstScope.
Canonical JSON
Three rules make the two implementations agree byte for byte:
- object keys sort by UTF-16 code unit, which is what comparing JavaScript strings does;
- numbers print with
String(number), the ECMAScript algorithm RFC 8785 requires; - a number is canonicalizable when it is finite and, if integral, no larger in magnitude than
Number.MAX_SAFE_INTEGER. Larger integers are refused rather than rounded: every counter and clock in these contracts is aU64decimal string. The rule is on the value, not on how it was written, becauseJSON.parsecannot tell1e21from the same digits written out.
parseStrict is a small recursive-descent parser rather than a wrapper around JSON.parse,
which keeps the last of two duplicate keys instead of failing.
Digests use node:crypto. This package is contract tooling for services and tests, not
browser code; the presentation layer consumes the public feed package instead.
Tests
npm test --workspace @flybrain/session-types
npm run typecheck --workspace @flybrain/session-types
Nine files, all fixture-driven. The one that says the most about the two implementations is in
tests/checkpoint.test.ts: a FLYSESS1 envelope written here is byte-identical to the one the
Rust crate wrote into the fixture.