{"record":{"id":"37ae5c4ead847802","repo":"HumanSignal/label-studio","slug":"choose-a-supported-column-type","errorCode":null,"errorMessage":"Choose a supported column type.","messagePattern":"Choose a supported column type\\.","errorType":"validation","errorClass":"ValidationError","httpStatus":400,"severity":"error","filePath":"label_studio/data_manager/actions/data_columns.py","lineNumber":35,"sourceCode":"from rest_framework.exceptions import PermissionDenied, ValidationError\nfrom tasks.models import Task\n\nall_permissions = AllPermissions()\n\n\ndef add_or_modify_columns_enabled(project):\n    return flag_set('fflag_utc_1012_add_or_modify_columns', organization=project.organization)\n\n\ndef _validate_column_request(request_data, project):\n    value_name = (\n        request_data.get('column_name') or request_data.get('value_name') or request_data.get('existing_column')\n    )\n    value_type = request_data.get('value_type', 'String')\n    value = request_data.get('value', '')\n\n    if value_type not in {'String', 'Number', 'Expression'}:\n        raise ValidationError({'value_type': 'Choose a supported column type.'})\n\n    if not isinstance(value_name, str) or not value_name.strip():\n        raise ValidationError({'column_name': 'Select an existing column or enter a new column name.'})\n\n    value_name = value_name.strip()\n    column_exists = value_name in project.summary.all_data_columns\n    if not column_exists:\n        column_exists = project.tasks.filter(data__has_key=value_name).exists()\n    mode = 'update' if column_exists else 'add'\n    # Existing columns (e.g. imported spreadsheet headers) stay editable, but a new column must be\n    # one the Data Manager can filter and sort on.\n    if mode == 'add' and not is_queryable_column_name(value_name):\n        raise ValidationError(\n            {'column_name': f'Column name cannot contain {UNQUERYABLE_COLUMN_NAME_CHARACTERS}.'},\n        )\n    try:\n        value = {'String': str, 'Number': float, 'Expression': str}[value_type](value)\n    except (TypeError, ValueError) as exc:","sourceCodeStart":17,"sourceCodeEnd":53,"githubUrl":"https://github.com/HumanSignal/label-studio/blob/0b49e9b53917880baf1dd85d574fe5541a9aafb2/label_studio/data_manager/actions/data_columns.py#L17-L53","documentation":"_validate_column_request checks request_data['value_type'] against the allowed set {'String','Number','Expression'}. Any other value_type raises ValidationError {'value_type': 'Choose a supported column type.'}. It is a strict input validation on the Add/Update Columns action payload.","triggerScenarios":"Submitting the add_data_field action with value_type set to e.g. 'Int', 'string' (wrong case), 'Boolean', or an empty value_type other than the default.","commonSituations":"Custom scripts calling the Data Manager action API with a guessed value_type; frontend sending value_type in the wrong case; API changed between versions adding/removing supported types.","solutions":["Send value_type exactly as one of 'String', 'Number', or 'Expression' (case-sensitive).","Omit value_type to get the default 'String'.","Fix the calling client to normalize value_type before submitting."],"exampleFix":"// before\n{'value_type': 'Integer', 'value': '42', 'column_name': 'score'}\n// after\n{'value_type': 'Number', 'value': '42', 'column_name': 'score'}","handlingStrategy":"validation","validationCode":"ALLOWED = {'String', 'Number', 'Expression'}\nassert request_data.get('value_type', 'String') in ALLOWED, 'value_type must be String, Number, or Expression'","typeGuard":"def has_valid_value_type(payload):\n    return payload.get('value_type', 'String') in {'String', 'Number', 'Expression'}","tryCatchPattern":"from rest_framework.exceptions import ValidationError\ntry:\n    add_data_field(project, qs, request=request)\nexcept ValidationError as e:\n    handle_field_errors(e.message_dict)  # {'value_type': [...]}","preventionTips":["Normalize value_type case before sending.","Default to 'String' when unsure.","Keep the client dropdown limited to the three supported types."],"tags":["django","validation","data-manager","columns"],"backgroundTag":"schema-validation-failed","analyzedSha":"0b49e9b53917880baf1dd85d574fe5541a9aafb2","analyzedAt":"2026-08-29T00:39:52.578Z","schemaVersion":2},"datasetVersion":"2026-08-29T02:17:18.158Z"}