apache/beam · error

error decoding bool: received invalid value

Error message

error decoding bool: received invalid value %v

What it means

This error comes from the Beam Go SDK's boolDecoder in exec/coder.go. During decoding of a wire-encoded boolean, the decoder found a byte that is neither 0 nor 1, so it cannot reconstruct a bool FullValue. It indicates corrupt or non-conforming encoded data rather than user-facing API misuse.

Solutions

1. Verify the coder registry and coder IDs match between pipeline construction and the worker runtime (same Beam SDK version).
2. Re-generate or clear any cached/serialized data (state caches, test fixtures) that may be corrupted.
3. Check that stream offsets and reader boundaries are aligned to element boundaries; a partial read yields invalid bytes.
4. Log the raw byte value (%v) to identify what is actually being read and trace where the stream diverged.

Example fix

// before: decoding raw bytes with mismatched coder
dec := exec.MakeElementDecoder(badCoder)
fv, err := dec.Decode(r)
// after: ensure coder comes from the same model pipeline / registry
dec := exec.MakeElementDecoder(coder.FromProto(modelPipelineComponents))
fv, err := dec.Decode(r)
if err != nil {
    return fmt.Errorf("bool decode failed, check coder consistency: %w", err)
}

if b != 0 && b != 1 { return fmt.Errorf("invalid bool byte %d before decode", b) }

func isValidBoolByte(b byte) bool { return b == 0 || b == 1 }

fv, err := dec.Decode(r)
if err != nil {
    if strings.Contains(err.Error(), "error decoding bool") {
        return fmt.Errorf("corrupt stream or coder mismatch: %w", err)
    }
    return err
}

When it happens

Trigger: Calling Decode/DecodeTo on a stream whose underlying bytes were produced with a different coder, truncated mid-element, or manually crafted so the bool byte is not 0 or 1.

Common situations: Corrupted pipeline artifacts or state caches, mismatched coder versions between job submitter and worker, manually edited captured streams, or reading a stream offset into the middle of an element.

Related errors

• array len mismatch. decoding
• CoderException
• Could not decode provided windows with the provided window…
• decodeStream value decode failed
• Encountered unexpected value for null indicator

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/2a93f85e6de96014. Report an issue: GitHub.

Appendix: source

Thrown at sdks/go/pkg/beam/core/runtime/exec/coder.go:373

func (*boolDecoder) DecodeTo(r io.Reader, fv *FullValue) error {
	// Encoding: false = 0, true = 1
	b := make([]byte, 1)
	if err := ioutilx.ReadNBufUnsafe(r, b); err != nil {
		if err == io.EOF {
			return err
		}
		return fmt.Errorf("error decoding bool: %v", err)
	}
	switch b[0] {
	case 0:
		*fv = FullValue{Elm: false}
		return nil
	case 1:
		*fv = FullValue{Elm: true}
		return nil
	}
	return fmt.Errorf("error decoding bool: received invalid value %v", b)
}

func (d *boolDecoder) Decode(r io.Reader) (*FullValue, error) {
	fv := &FullValue{}
	if err := d.DecodeTo(r, fv); err != nil {
		return nil, err
	}
	return fv, nil
}

type varIntEncoder struct{}

func (*varIntEncoder) Encode(val *FullValue, w io.Writer) error {
	// Encoding: beam varint
	return coder.EncodeVarInt(val.Elm.(int64), w)
}

type varIntDecoder struct{}

View on GitHub (pinned to 12126d8942)