Hmbown/CodeWhale · error · Error

Invalid pet checkpoint.

Error message

Invalid pet checkpoint.

What it means

fromRecording allows start and checkpoint keys to be absent, but if a key is present it must be a truthy checkpoint object. A recording carrying `start: null` or `checkpoint: null` (present but empty) is internally inconsistent — the producer intended a segmented/checkpointed recording but the data is missing — so this error is thrown.

Solutions

1. Remove the falsy start/checkpoint keys entirely from the recording object before restoring.
2. Restore the missing checkpoint from the segment archive that produced it.
3. Re-record or re-export the segment from a live world via prepareSegment().
4. Fix the producer/serialization step to omit empty optional keys instead of writing null.

Example fix

// before
const r = JSON.parse(raw); // { ..., start: null, checkpoint: {...} }
const world = PetWorld.fromRecording(points, r); // throws
// after
const r = JSON.parse(raw);
if (r.start === null) delete r.start;
if (r.checkpoint === null) delete r.checkpoint;
const world = PetWorld.fromRecording(points, r);

if ('start' in r && !r.start) delete r.start;
if ('checkpoint' in r && !r.checkpoint) delete r.checkpoint;

const hasCheckpoint = (r, k) => !(k in r) || (r[k] !== null && typeof r[k] === 'object');

try {
  world = PetWorld.fromRecording(points, r);
} catch (err) {
  if (err.message === 'Invalid pet checkpoint.')
    world = PetWorld.fromRecording(points, { ...r, start: undefined, checkpoint: undefined });
  else throw err;
}

When it happens

Trigger: Calling `PetWorld.fromRecording(points, r)` where r.start or r.checkpoint is explicitly present but null/undefined/0/'' (e.g. `{start: null}` or `{checkpoint: undefined}` serialized as a present-but-falsy key).

Common situations: Serialization layers that write null for missing optional fields; hand-merging segment files; a producer bug that wrote the keys without populating them; JSON round-trips through schemas that normalize undefined to null.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• Invalid pet checkpoint.
• Invalid pet checkpoint.
• Invalid pet particle checkpoint.
• Invalid pet particle checkpoint.
• Invalid pet recording.

AI-assisted analysis of Hmbown/CodeWhale@73e0f67d83 (2026-09-22). Data as JSON: /api/errors/9c21e6c1017fe679. Report an issue: GitHub.

Appendix: source

Thrown at crates/tui/src/tui/pet_watch/pet-native.js:253

    }
    recording(withCheckpoint = true, completed = false) {
        const tapeEnd = completed ? this.bucketIndex + 1 : this.tapeLog.length;
        const inputEnd = completed ? this.interactionIndex : this.interactionLog.length;
        const history = this.historyDigest(tapeEnd, inputEnd);
        return { petReplayVersion: this.segmented ? 2 : 1, expressionVersion: this.sim.expressionVersion,
            tape: this.tapeLog.slice(0, tapeEnd), interactions: this.interactionLog.slice(0, inputEnd).map(e => ({ ...e })),
            ...(this.origin ? { start: { ...structuredClone(this.origin), hasTelemetry: this.hasTelemetry, history } } : {}),
            ...(withCheckpoint ? { checkpoint: { ...this.checkpoint(), history } } : {}) };
    }
    static fromRecording(points, value) {
        const r = value;
        if (!r || ![1, 2].includes(r.petReplayVersion) || !Array.isArray(r.tape) || !Array.isArray(r.interactions))
            throw new Error('Invalid pet recording.');
        const version = r.expressionVersion === undefined ? 1 : r.expressionVersion;
        if (![1, 2].includes(version))
            throw new Error('Unsupported pet expression version.');
        if (r.checkpoint !== undefined && !r.checkpoint || r.start !== undefined && !r.start)
            throw new Error('Invalid pet checkpoint.');
        for (const c of [r.start, r.checkpoint])
            if (c && (c.sim?.expressionVersion ?? 1) !== version)
                throw new Error('Pet expression version does not match its checkpoint.');
        if (r.petReplayVersion === 1 && (r.start || r.checkpoint && r.checkpoint.petCheckpointVersion !== 1))
            throw new Error('Invalid legacy pet recording.');
        if (r.petReplayVersion === 2 && (!r.start || r.start.petCheckpointVersion !== 2 || r.start.historyStart !== r.start.tick))
            throw new Error('The recording segment is missing its starting checkpoint.');
        const first = r.start && PetWorld.restore(points, r.tape, r.interactions, r.start);
        const world = r.checkpoint ? PetWorld.restore(points, r.tape, r.interactions, r.checkpoint) : first ?? new PetWorld(points, r.tape, r.interactions, version);
        if (first) {
            if (!world.segmented || world.tick < first.tick || r.checkpoint && r.checkpoint.historyStart !== first.tick)
                throw new Error('Pet segment checkpoints do not agree.');
            world.origin = first.checkpoint();
        }
        return world;
    }
    /** Retire only consumed input. The exact origin makes each archived segment
     * independently replayable; no particle, random stream or score is reset. */

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