apache/beam · error · IllegalStateException

Unexpected marshalling type awsType

Error message

Unexpected marshalling type awsType

What it means

AwsTypes' converter factory (create) switches on an SdkField's MarshallingType and throws IllegalStateException 'Unexpected marshalling type <type>' when the field's marshalling type has no converter. Reached from fieldValueGetters and recursive create calls when converting AWS POJO values to Beam Row values.

Solutions

1. Upgrade Beam to a version whose converter handles the marshalling type
2. Verify AWS SDK v2 and Beam AWS2 module versions are aligned
3. Avoid the offending field by mapping only supported fields

Example fix

// before
Row row = rowForAwsModel(pojoWithDocumentField);
// after
MyPojo trimmed = pojoWithDocumentField.toBuilder()
    .clearDocumentField()
    .build();
Row row = rowForAwsModel(trimmed); // only supported marshalling types

MarshallingType<?> t = field.marshallingType(); if (needsConversion(field) && !SUPPORTED.contains(t)) { /* skip or map manually */ }

try { row = rowFor(pojo); } catch (IllegalStateException e) { /* fall back to field-by-field manual conversion */ }

When it happens

Trigger: Converting an AWS SDK POJO to a Beam Row where a field's marshalling type is neither scalar (string/int/etc.), LIST, MAP, nor another supported type; nested fields recursively hitting the same branch.

Common situations: Version skew: AWS SDK added a new MarshallingType (e.g. for document types) that the Beam converter doesn't know; using AwsSchemaProvider on POJOs with exotic field types.

Related errors

• Type of field is unknown.
• Array schema is not properly formatted or unsupported
• Cannot select a subfield of a non-composite type.
• Could not infer beam type for thrift field
• Field type not matched.

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/f6bdd73e84a43119. Report an issue: GitHub.

Appendix: source

Thrown at sdks/java/io/amazon-web-services2/src/main/java/org/apache/beam/sdk/io/aws2/schemas/AwsTypes.java:183

    SerializableFunction create(SdkField<?> field) {
      return create(IDENTITY, field);
    }

    SerializableFunction create(SerializableFunction fn, SdkField<?> field) {
      MarshallingType<?> awsType = field.marshallingType();
      SerializableFunction converter;
      if (awsType == SDK_POJO) {
        converter = pojoTypeConverter(field);
      } else if (awsType == INSTANT) {
        converter = instantConverter;
      } else if (awsType == SDK_BYTES) {
        converter = bytesConverter;
      } else if (awsType == LIST) {
        converter = transformList(create(elementField(field)));
      } else if (awsType == MAP) {
        converter = transformMap(create(valueField(field)));
      } else {
        throw new IllegalStateException("Unexpected marshalling type " + awsType);
      }
      return fn != IDENTITY ? andThen(fn, nullSafe(converter)) : nullSafe(converter);
    }

    boolean needsConversion(SdkField<?> field) {
      MarshallingType<?> type = field.marshallingType();
      return (convertPojoType && type.equals(MarshallingType.SDK_POJO))
          || type.equals(INSTANT)
          || type.equals(SDK_BYTES)
          || (type.equals(MAP) && needsConversion(valueField(field)))
          || (type.equals(LIST) && needsConversion(elementField(field)));
    }

    @SuppressWarnings("nullness")
    private static SerializableFunction andThen(
        SerializableFunction fn1, SerializableFunction fn2) {
      return v -> fn2.apply(fn1.apply(v));
    }

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