{"record":{"id":"a98798058c98c1b0","repo":"apache/flink","slug":"the-field-is-invalid-a98798","errorCode":null,"errorMessage":"The field  ({}) is invalid.","messagePattern":"The field  \\((.+?)\\) is invalid\\.","errorType":"validation","errorClass":"IllegalArgumentException","httpStatus":null,"severity":"error","filePath":"flink-core/src/main/java/org/apache/flink/api/common/io/GenericCsvInputFormat.java","lineNumber":571,"sourceCode":"        int i = 0;\n        for (Map.Entry<Integer, Class<?>> entry : map.entrySet()) {\n            positions[i] = entry.getKey();\n            types[i] = entry.getValue();\n            i++;\n        }\n    }\n\n    protected static void checkForMonotonousOrder(int[] positions, Class<?>[] types) {\n        if (positions.length != types.length) {\n            throw new IllegalArgumentException(\n                    \"The positions and types must be of the same length\");\n        }\n\n        int lastPos = -1;\n\n        for (int i = 0; i < positions.length; i++) {\n            if (positions[i] < 0) {\n                throw new IllegalArgumentException(\n                        \"The field \" + \" (\" + positions[i] + \") is invalid.\");\n            }\n            if (types[i] == null) {\n                throw new IllegalArgumentException(\"The type \" + i + \" is invalid (null)\");\n            }\n\n            if (positions[i] <= lastPos) {\n                throw new IllegalArgumentException(\n                        \"The positions must be strictly increasing (no permutations are supported).\");\n            }\n\n            lastPos = positions[i];\n        }\n    }\n\n    private static int max(int[] ints) {\n        checkArgument(ints.length > 0);\n","sourceCodeStart":553,"sourceCodeEnd":589,"githubUrl":"https://github.com/apache/flink/blob/2f3c205e9266cb30240eb7f4fdab15cad629a70f/flink-core/src/main/java/org/apache/flink/api/common/io/GenericCsvInputFormat.java#L553-L589","documentation":"Thrown by checkForMonotonousOrder when a position is negative. CSV column positions must be >= 0. (The message here is well-formed: 'The field (-1) is invalid.', unlike the parallel check in checkAndCoSort which has a typo.) This is a programming-error guard.","triggerScenarios":"A subclass passes a positions array containing a negative value, e.g. from off-by-one arithmetic, a sentinel not filtered, or 0-vs-1 based indexing confusion.","commonSituations":"Index = something - 1 when something is 0; sentinel -1 leaking through; refactor leftover; 1-based source data treated as 0-based.","solutions":["Ensure all positions are >= 0 before calling checkForMonotonousOrder.","Audit index arithmetic for off-by-one and 0-vs-1 base mistakes.","Strip sentinel/placeholder indices before the call."],"exampleFix":"// before\ncheckForMonotonousOrder(new int[]{-1,1,2}, types);\n// after\ncheckForMonotonousOrder(new int[]{0,1,2}, types);","handlingStrategy":"validation","validationCode":"for (int p : positions) {\n    if (p < 0) throw new IllegalArgumentException(\"Negative CSV position: \" + p);\n}\ncheckForMonotonousOrder(positions, types);","typeGuard":"static int nonNegIndex(int i) {\n    if (i < 0) throw new IllegalArgumentException(\"index must be >= 0, got \" + i);\n    return i;\n}","tryCatchPattern":"try {\n    checkForMonotonousOrder(positions, types);\n} catch (IllegalArgumentException e) {\n    if (e.getMessage().contains(\"invalid\")) {\n        throw new IllegalArgumentException(\"Negative CSV position: \" + Arrays.toString(positions), e);\n    }\n    throw e;\n}","preventionTips":["Strip sentinel/placeholder indices before the call.","Audit index arithmetic for off-by-one and 0-vs-1 base mistakes.","Unit-test positions for non-negativity."],"tags":["csv","input-format","validation","api-misuse"],"backgroundTag":null,"analyzedSha":"2f3c205e9266cb30240eb7f4fdab15cad629a70f","analyzedAt":"2026-08-14T08:48:24.518Z","schemaVersion":2},"datasetVersion":"2026-08-14T10:17:34.591Z"}