Hmbown/CodeWhale · error · Error

Codewhale runtime event file is empty.

Error message

Codewhale runtime event file is empty.

What it means

fromCodewhaleRuntime() builds a CodewhaleRuntimeTrace from a parsed array of runtime event records. The library refuses to construct a trace from an empty record list because downstream code (origin-time anchoring, snapshot building) assumes at least one event; an empty input would produce a trace with no origin and no events. It throws this error before any trace object is allocated.

Solutions

  1. Check that the runtime event file is non-empty (file size > 0 and at least one parsable JSON line) before calling fromCodewhaleRuntime.
  2. Re-export the runtime events from the Codewhale session and verify the export wrote records.
  3. If upstream filtering can legitimately drop all rows, handle the empty case in the caller instead of invoking fromCodewhaleRuntime.

Example fix

// before
const trace = fromCodewhaleRuntime(records, file);
// after
if (!records.length) { console.warn(`skipping ${file}: no runtime events`); return; }
const trace = fromCodewhaleRuntime(records, file);
Defensive patterns

Strategy: validation

Validate before calling

if (!Array.isArray(records) || records.length === 0) throw new Error(`no runtime events in ${file}`);
const trace = fromCodewhaleRuntime(records, file);

Type guard

const hasRecords = (v: unknown): v is object[] => Array.isArray(v) && v.length > 0;

Try / catch

let trace;
try { trace = fromCodewhaleRuntime(records, file); }
catch (e) { if (e.message.includes('event file is empty')) return null; throw e; }

Prevention

When it happens

Trigger: Calling fromCodewhaleRuntime([], ...) — e.g. a runtime event file that parses to zero JSON lines, a file containing only whitespace or comments, or a filtered/decoder step that dropped every record before the call.

Common situations: Exporting a Codewhale session before any runtime events were recorded, truncating a .jsonl export with a shell command that leaves only a trailing newline, or piping an empty stream into the importer.

Understand the failure class

Background: EmptyResultError / "no results found": when an API or scraper succeeds but returns zero rows — this error's family across 9 libraries.

Related errors

AI-assisted analysis of Hmbown/CodeWhale@433685b202 (2026-09-15). Data as JSON: /api/errors/8d4042ae43aadf2c. Report an issue: GitHub.

Appendix: source

Thrown at pet/ios/Resources/pet-native.js:2512

            privacy: 'redact',
            warnings: [...new Set(warnings)],
            metadata: {
                sourceFormat: 'codewhale.runtime-events/v2',
                timeBasis: 'wall-clock',
                sourceFilename: filename,
                threadId,
                model,
                skippedDeltas,
                recordCount: this.recordCount,
                timeUnit: 'ms',
            },
        };
    }
}
exports.CodewhaleRuntimeTrace = CodewhaleRuntimeTrace;
function fromCodewhaleRuntime(records, filename = 'Codewhale runtime', maxEvents = 250_000) {
    if (!records.length)
        throw new Error('Codewhale runtime event file is empty.');
    const trace = new CodewhaleRuntimeTrace(filename, maxEvents);
    trace.append(records);
    return trace.snapshot();
}
/** The journal owns request state until a matching terminal receipt. A live
 * driver may confirm that state only while its cursor-checked stream is healthy.
 * Ordinary open tool spans remain unknown-duration; no execution is inferred. */
function observeRuntimeRequests(trace, observedThrough) {
    const origin = Date.parse(trace.originTime ?? '');
    if (trace.metadata.sourceFormat !== 'codewhale.runtime-events/v2' || !Number.isFinite(origin)
        || !Number.isFinite(observedThrough))
        throw new Error('Invalid Runtime observation horizon.');
    const at = observedThrough - origin;
    const events = trace.events.map(e => e.openEnded && e.attributes['whalesong.waiting'] === true && at >= e.startTime
        ? { ...e, endTime: at, openEnded: false } : e);
    return { ...trace, events, duration: Math.max(trace.duration, at) };
}

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