{"record":{"id":"907698ec0b21f2ae","repo":"apache/flink","slug":"unknown-field-name-s-for-mapping-to-a-row-posit-907698","errorCode":null,"errorMessage":"Unknown field name '%s' for mapping to a row position. Available names are: %s","messagePattern":"Unknown field name '(.+?)' for mapping to a row position\\. Available names are: (.+?)","errorType":"exception","errorClass":"IllegalArgumentException","httpStatus":null,"severity":"error","filePath":"flink-core/src/main/java/org/apache/flink/types/Row.java","lineNumber":348,"sourceCode":"                    \"Accessing a field by position is not supported in name-based field mode.\");\n        }\n    }\n\n    /**\n     * Sets the field's content using the specified field name.\n     *\n     * <p>Note: The row must operate in name-based field mode.\n     *\n     * @param name the name of the field\n     * @param value the value to be assigned to the field\n     */\n    public void setField(String name, @Nullable Object value) {\n        if (fieldByName != null) {\n            fieldByName.put(name, value);\n        } else if (positionByName != null) {\n            final Integer pos = positionByName.get(name);\n            if (pos == null) {\n                throw new IllegalArgumentException(\n                        String.format(\n                                \"Unknown field name '%s' for mapping to a row position. \"\n                                        + \"Available names are: %s\",\n                                name, positionByName.keySet()));\n            }\n            assert fieldByPosition != null;\n            fieldByPosition[pos] = value;\n        } else {\n            throw new IllegalArgumentException(\n                    \"Accessing a field by name is not supported in position-based field mode.\");\n        }\n    }\n\n    /**\n     * Returns the set of field names if this row operates in name-based field mode, otherwise null.\n     *\n     * <p>This method is a helper method for serializers and converters but can also be useful for\n     * other row transformations.","sourceCodeStart":330,"sourceCodeEnd":366,"githubUrl":"https://github.com/apache/flink/blob/2f3c205e9266cb30240eb7f4fdab15cad629a70f/flink-core/src/main/java/org/apache/flink/types/Row.java#L330-L366","documentation":"In Row's hybrid mode (positionByName != null), setField(String name, value) resolves the name to a position via the positionByName map. When the name is absent, it throws an IllegalArgumentException that helpfully lists all available names (positionByName.keySet()), making typos and schema drift easy to diagnose.","triggerScenarios":"Calling setField(name, value) on a hybrid row where name is not in the attached name list — misspelled, different case, or a field from a newer/older schema.","commonSituations":"Connector column mappings after upstream renames; configuration-driven field names flowing into row construction; inconsistent casing conventions (camelCase vs snake_case) between producer and consumer.","solutions":["Use one of the names printed in the exception message (positionByName.keySet())","Validate the name against row.getFieldNames(true) before writing","Share field-name constants between the code that defines the row and the code that fills it"],"exampleFix":"// before\nrow.setField(\"userId\", 7); // available: [user_id, name]\n\n// after\nrow.setField(\"user_id\", 7);","handlingStrategy":"validation","validationCode":"List<String> names = row.getFieldNames(true);\nif (names != null && !names.contains(name)) {\n    throw new IllegalArgumentException(\"Unknown '\" + name + \"'; available: \" + names);\n}\nrow.setField(name, value);","typeGuard":"static boolean canSetByName(Row row, String name) {\n    List<String> names = row.getFieldNames(true);\n    return names != null && names.contains(name);\n}","tryCatchPattern":"catch (IllegalArgumentException e) { // message already lists available names; fix the mapping }","preventionTips":["Validate configurable field names at startup","Keep producer/consumer schemas in sync","Read the available-names list in the exception"],"tags":["flink","row","field-name","illegal-argument","schema-mismatch"],"backgroundTag":null,"analyzedSha":"2f3c205e9266cb30240eb7f4fdab15cad629a70f","analyzedAt":"2026-08-14T08:48:24.518Z","schemaVersion":2},"datasetVersion":"2026-08-14T10:17:34.591Z"}