{"record":{"id":"9f8f996a0a7c4130","repo":"apache/beam","slug":"could-not-infer-beam-type-for-thrift-field-s","errorCode":null,"errorMessage":"Could not infer beam type for thrift field: %s","messagePattern":"Could not infer beam type for thrift field: (.+?)","errorType":"exception","errorClass":"IllegalStateException","httpStatus":null,"severity":"error","filePath":"sdks/java/io/thrift/src/main/java/org/apache/beam/sdk/io/thrift/ThriftSchema.java","lineNumber":206,"sourceCode":"\n  private static <X> X throwingCombiner(X lhs, X rhs) {\n    throw new IllegalStateException();\n  }\n\n  private Schema.Field beamField(FieldMetaData fieldDescriptor) {\n    try {\n      final FieldType type = beamType(fieldDescriptor.valueMetaData);\n      switch (fieldDescriptor.requirementType) {\n        case TFieldRequirementType.REQUIRED:\n          return Schema.Field.of(fieldDescriptor.fieldName, type);\n        case TFieldRequirementType.DEFAULT:\n          // aka \"opt-in, req-out\", so it's safest to fall through to nullable\n        case TFieldRequirementType.OPTIONAL:\n        default:\n          return Schema.Field.nullable(fieldDescriptor.fieldName, type);\n      }\n    } catch (Exception e) {\n      throw new IllegalStateException(\n          \"Could not infer beam type for thrift field: \" + fieldDescriptor.fieldName, e);\n    }\n  }\n\n  @SuppressWarnings(\"rawtypes\")\n  @Override\n  public <T> @NonNull List<FieldValueGetter<@NonNull T, Object>> fieldValueGetters(\n      @NonNull TypeDescriptor<T> targetTypeDescriptor, @NonNull Schema schema) {\n    return schemaFieldDescriptors(targetTypeDescriptor.getRawType(), schema).keySet().stream()\n        .<FieldExtractor<TFieldIdEnum, @NonNull T>>map(FieldExtractor::new)\n        .collect(Collectors.toList());\n  }\n\n  @Override\n  public @NonNull List<FieldValueTypeInformation> fieldValueTypeInformations(\n      @NonNull TypeDescriptor<?> targetTypeDescriptor, @NonNull Schema schema) {\n    return schemaFieldDescriptors(targetTypeDescriptor.getRawType(), schema).values().stream()\n        .map(","sourceCodeStart":188,"sourceCodeEnd":224,"githubUrl":"https://github.com/apache/beam/blob/12126d8942aaf848030c478b4c6a28c6af861c66/sdks/java/io/thrift/src/main/java/org/apache/beam/sdk/io/thrift/ThriftSchema.java#L188-L224","documentation":"ThriftSchema.beamField maps a single thrift field's metadata to a Beam Schema field. If the thrift field's type cannot be translated into a Beam type (unsupported containers, unusual nested structs, etc.), the generic Exception is wrapped in an IllegalStateException with this message naming the field.","triggerScenarios":"Inferring a schema for a thrift class containing a field type ThriftSchema cannot map — e.g. unsupported collection element types, maps with complex keys, or custom types lacking a conversion.","commonSituations":"IDLs using map<struct, struct> or other exotic combinations; fields added by a newer thrift generator version that the schema mapper doesn't handle; deeply nested unions inside collections.","solutions":["Read the wrapped cause to see exactly why the field type failed to map","Simplify the field's thrift type (e.g. avoid struct keys in maps) or convert it to a supported type in the IDL","Pin to a Beam version whose ThriftSchema supports your field types, or file/patch the mapper for the missing type"],"exampleFix":"// before (IDL)\nmap<ThriftKey, ThriftValue> complexMap  // unsupported key type\n// after (IDL)\nmap<string, ThriftValue> complexMap","handlingStrategy":"validation","validationCode":"for (Map.Entry<_Fields, FieldMetaData> f : FieldMetaData.getStructMetaDataMap(ThriftRecord.class).entrySet()) { try { ThriftSchema.provider().schemaFor(TypeDescriptor.of(ThriftRecord.class)); } catch (IllegalStateException e) { /* field unmappable: fix IDL */ } }","typeGuard":null,"tryCatchPattern":"try { schema = ThriftSchema.provider().schemaFor(td); } catch (IllegalStateException e) { LOG.error(\"Unmappable thrift field: {}\", e.getMessage(), e.getCause()); throw e; }","preventionTips":["Prefer simple thrift types (string/i32/i64/list/map with primitive keys)","Test schema inference on all thrift types in CI","Keep Beam updated for newly supported thrift type mappings"],"tags":["java","thrift","schema","type-mapping"],"backgroundTag":"unsupported-operation","analyzedSha":"12126d8942aaf848030c478b4c6a28c6af861c66","analyzedAt":"2026-09-13T01:50:10.254Z","contentChangedAt":"2026-09-13T01:50:10.254Z","schemaVersion":2},"datasetVersion":"2026-09-20T03:17:13.778Z"}