GopeedLab/gopeed · error

promise rejected

Error message

promise rejected

What it means

exportJSError in the stream module (pkg/download/engine/inject/stream/module.go:537-539) is the same conversion helper as the engine's: a promise rejection value of undefined/null, or a nil goja.Value, cannot yield a message, so the error degrades to the generic 'promise rejected'. Any Error object, string, or exported error would have produced a specific message instead.

Source

Thrown at pkg/download/engine/inject/stream/module.go:539

				})
				if _, err := thenFn(value, onFulfilled, onRejected); err != nil {
					send(nil, err)
				}
				return
			}
		}
		send(value, nil)
	})
	if !ok {
		return nil, errors.New("engine loop terminated")
	}
	res := <-ch
	return res.value, res.err
}

func exportJSError(value goja.Value) error {
	if value == nil || goja.IsUndefined(value) || goja.IsNull(value) {
		return errors.New("promise rejected")
	}
	if err, ok := value.Export().(error); ok {
		return err
	}
	stack := value.String()
	if ro, ok := value.(*goja.Object); ok {
		stackVal := ro.Get("stack")
		if stackVal != nil && stackVal.String() != "" {
			stack = stackVal.String()
		}
	}
	return errors.New(stack)
}

type fetchRegistry struct {
	mu      sync.Mutex
	streams map[string]*fetchStream
	ctx     context.Context

View on GitHub (pinned to 7b7327ffb3)

Solutions

1. Instrument the script: wrap stream calls with .catch(e => { throw (e === undefined ? new Error('stream rejected without reason') : e })
2. Fix scripts to reject with Error objects: reject(new Error('stream aborted'))
3. Enable any script-side logging the engine provides to capture the failure site
4. Address the root cause once a real message is recoverable

Example fix

// before (script)
stream.open(u).then(null, () => reject())

// after (script)
stream.open(u).then(null, (e) => reject(e instanceof Error ? e : new Error('stream open failed: ' + String(e))))

// Script-side: normalize rejections before they cross into Go
// .catch(e => { throw e == null ? new Error('stream rejected without reason') : e })

// Script-side guard:
function norm(e) { return e == null ? new Error('rejected without reason') : e }

if err != nil && err.Error() == "promise rejected" {
    // stream rejection had no reason value: add script-side catch logging to find the cause
}

When it happens

Trigger: Stream-related script code rejects with no argument (reject()) or throws undefined/null (common in minified bundles); a fetch/stream polyfill signaling failure with reject(undefined); rejection callbacks invoked with zero arguments.

Common situations: Third-party resolver scripts with bare undefined throws; debugging dead-ends because the message carries no cause — it strictly means 'rejected without a reason value'.

Related errors

• promise rejected
• promise.then is not callable
• promise.then is not callable
• panic: %v
• EVALUATION_FAILED

AI-assisted analysis of GopeedLab/gopeed@7b7327ffb3 (2026-08-16). Data as JSON: /api/errors/837c7ec5fdacc597. Report an issue: GitHub.