apache/flink · error · PbCodegenException

do not support field type:

Error message

do not support field type: 

What it means

getTypeStrFromProto maps a proto field's JavaType to a Java type string used in generated code. The default branch throws for unhandled JavaTypes — typically MESSAGE or ENUM landing here, since the caller should have routed those elsewhere. A throw here indicates an inconsistent dispatch path (bug) or a protobuf runtime version exposing types this flink-protobuf build does not know.

Source

Thrown at flink-formats/flink-protobuf/src/main/java/org/apache/flink/formats/protobuf/util/PbCodegenUtils.java:126

                typeStr = "String";
                break;
            case ENUM:
                typeStr = PbFormatUtils.getFullJavaName(fd.getEnumType());
                break;
            case FLOAT:
                typeStr = "Float";
                break;
            case DOUBLE:
                typeStr = "Double";
                break;
            case BYTE_STRING:
                typeStr = "ByteString";
                break;
            case BOOLEAN:
                typeStr = "Boolean";
                break;
            default:
                throw new PbCodegenException("do not support field type: " + fd.getJavaType());
        }
        if (isList) {
            return "List<" + typeStr + ">";
        } else {
            return typeStr;
        }
    }

    /**
     * Get java type str from {@link LogicalType} which directly fetched from flink type.
     *
     * @return The returned code phrase will be used as java type str in codegen sections.
     */
    public static String getTypeStrFromLogicType(LogicalType type) {
        switch (type.getTypeRoot()) {
            case INTEGER:
                return "int";
            case BIGINT:

View on GitHub (pinned to 2f3c205e92)

Solutions

1. Diff the DDL against the current .proto; make message fields ROW(...) and enum fields INT/VARCHAR.
2. Regenerate the protobuf Java classes and ensure the pipeline compiles against them.
3. Pin compatible flink-protobuf and protobuf-java versions (do not override in user jars).
4. If consistent, report a JIRA — this default should be unreachable for valid dispatch.

Set<FieldDescriptor.JavaType> supported = EnumSet.of(
    FieldDescriptor.JavaType.INT, FieldDescriptor.JavaType.LONG,
    FieldDescriptor.JavaType.FLOAT, FieldDescriptor.JavaType.DOUBLE,
    FieldDescriptor.JavaType.BOOLEAN, FieldDescriptor.JavaType.BYTE_STRING,
    FieldDescriptor.JavaType.STRING, FieldDescriptor.JavaType.ENUM);
if (!supported.contains(fd.getJavaType())) fail(fd);

When it happens

Trigger: A message/enum proto field being processed where only simple java types are expected, e.g. an array of messages whose element type string is requested from the wrong branch.

Common situations: Schema mismatch between DDL and proto class (message field declared as scalar); mismatched protobuf-java/flink-protobuf versions after an upgrade.

Related errors

• Do not support flink type:
• Illegal type for protobuf enum, only char/vachar/int/bigint
• Unsupported protobuf simple type:
• Do not support flink data type:
• Unsupported data type in schema:

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/eb0a4bfe3499dff3. Report an issue: GitHub.