apache/flink · error · java.lang.IllegalArgumentException

Union types are such as 'allOf', 'anyOf' etc. and extending…

Error message

Union types are such as 'allOf', 'anyOf' etc. and extending are not supported yet.

What it means

Fires when the schema node (or its resolved reference) contains 'allOf', 'anyOf', 'not', 'extends', or 'disallow' keywords, meaning it describes a union/combination type that cannot be represented as a single Flink TypeInformation. This is a deliberate converter limitation, not malformed input.

Solutions

  1. Address the cause reported by the error message: Union types are such as 'allOf', 'anyOf' etc. and extending are not supported yet.
  2. Verify the inputs, configuration values, and classpath/dependency setup related to this operation, then retry.

Example fix

Correct the condition described ("Union types are such as 'allOf', 'anyOf' etc. and extending are not supported yet.") and rerun the job or command.
Defensive patterns

Strategy: validation

When it happens

Trigger: Triggered at runtime when the operation fails because: Union types are such as 'allOf', 'anyOf' etc. and extending are not supported yet.

Common situations: Commonly caused by misconfiguration, missing dependencies or files, unsupported types or operations, or invalid user input leading to: Union types are such as 'allOf', 'anyOf' etc. and extending are not supported yet.

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/6def953f4f0abafb. Report an issue: GitHub.

Appendix: source

Thrown at flink-formats/flink-json/src/main/java/org/apache/flink/formats/json/JsonRowSchemaConverter.java:214

            final TypeInformation<?>[] types =
                    convertTypes(location + '/' + ONE_OF, node.get(ONE_OF), root);
            typeSet.addAll(Arrays.asList(types));
        }
        // use ONE_OF of reference as fallback
        else if (ref.isPresent() && ref.get().has(ONE_OF) && ref.get().get(ONE_OF).isArray()) {
            final TypeInformation<?>[] types =
                    convertTypes(
                            node.get(REF).asText() + '/' + ONE_OF, ref.get().get(ONE_OF), root);
            typeSet.addAll(Arrays.asList(types));
        }

        // validate no union types or extending
        if (node.has(ALL_OF)
                || node.has(ANY_OF)
                || node.has(NOT)
                || node.has(EXTENDS)
                || node.has(DISALLOW)) {
            throw new IllegalArgumentException(
                    "Union types are such as '"
                            + ALL_OF
                            + "', '"
                            + ANY_OF
                            + "' etc. "
                            + "and extending are not supported yet.");
        }

        // only a type (with null) is supported yet
        final List<TypeInformation<?>> types = new ArrayList<>(typeSet);
        if (types.size() == 0) {
            throw new IllegalArgumentException("No type could be found in node:" + location);
        } else if (types.size() > 2 || (types.size() == 2 && !types.contains(Types.VOID))) {
            throw new IllegalArgumentException(
                    "Union types with more than just a null type are not supported yet.");
        }

        // return the first non-void type or void

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