apache/iceberg · error · IllegalArgumentException

Unsupported type: ${primitive}

Error message

Unsupported type: ${primitive}

What it means

SparkPlannedAvroReader.primitive maps Avro primitive types (NULL, BOOLEAN, INT, LONG, FLOAT, DOUBLE, STRING, FIXED, BYTES, ENUM) to value readers. Any other Avro type (e.g. RECORD, ARRAY, MAP, UNION — which should be handled by other visit methods) reaching this switch throws IllegalArgumentException.

Source

Thrown at spark/v4.1/spark/src/main/java/org/apache/iceberg/spark/data/SparkPlannedAvroReader.java:194

        case LONG:
          return ValueReaders.longs();
        case FLOAT:
          if (partner != null && partner.typeId() == Type.TypeID.DOUBLE) {
            return ValueReaders.floatsAsDoubles();
          }
          return ValueReaders.floats();
        case DOUBLE:
          return ValueReaders.doubles();
        case STRING:
          return SparkValueReaders.strings();
        case FIXED:
          return ValueReaders.fixed(primitive.getFixedSize());
        case BYTES:
          return ValueReaders.bytes();
        case ENUM:
          return SparkValueReaders.enums(primitive.getEnumSymbols());
        default:
          throw new IllegalArgumentException("Unsupported type: " + primitive);
      }
    }
  }
}

View on GitHub (pinned to 86d9c8fc54)

Solutions

1. Verify the table schema matches the Avro file schema; fix the Iceberg schema so planning resolves each field to the right reader.
2. Re-write the Avro data with a standard schema.
3. Upgrade Iceberg if the file uses an Avro feature newer than the bundled version.

// ensure planned Iceberg schema fields align 1:1 with Avro primitives
avroSchema.getFields().forEach(f ->
    Preconditions.checkArgument(f.schema().getType().isPrimitive() ||
        f.schema().getType() == Schema.Type.ENUM ||
        f.schema().getType() == Schema.Type.FIXED,
        "Unexpected Avro type for field %s: %s", f.name(), f.schema().getType()));

When it happens

Trigger: A nested/non-primitive Avro type routed into the primitive visit method due to a schema-planning mismatch, or a corrupted/unusual schema where a primitive branch receives an unhandled type.

Common situations: Schema incompatibility between the planned Iceberg schema and the Avro file schema (fields resolved to unexpected types); custom Avro types.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• Unsupported type:
• Unsupported type: ${primitive}
• Unsupported type:
• Unknown logical type: {logicalType}
• Unknown type for int field. Type name:

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/9c1f8d26426d65e7. Report an issue: GitHub.