pathwaycom/pathway · error · ValueError

Unexpected argument for csv format: json_field_paths

Error message

Unexpected argument for csv format: json_field_paths

What it means

Error "Unexpected argument for csv format: json_field_paths" thrown in pathwaycom/pathway.

Source

Thrown at python/pathway/io/_utils.py:358

                f"The schema already declares a {METADATA_COLUMN_NAME!r} column, "
                f"which conflicts with 'with_metadata=True'. Either remove "
                f"{METADATA_COLUMN_NAME!r} from the schema or set "
                "'with_metadata=False'."
            )
        raise ValueError(
            f"{METADATA_COLUMN_NAME!r} is a reserved column name used by "
            "Pathway's connector metadata. Declaring it in the schema would "
            "be silently shadowed by the connector. Rename your column to "
            "something else, or set 'with_metadata=True' to receive the "
            "auto-generated metadata in this column."
        )
    if with_metadata:
        schema |= MetadataSchema

    schema, api_schema = read_schema(schema)
    if data_format_type == "dsv":
        if json_field_paths is not None:
            raise ValueError("Unexpected argument for csv format: json_field_paths")
        return schema, api.DataFormat(
            **api_schema,
            format_type=data_format_type,
            delimiter=",",
            schema_registry_settings=maybe_schema_registry_settings(
                schema_registry_settings
            ),
        )
    elif data_format_type == "jsonlines":
        if csv_settings is not None:
            raise ValueError("Unexpected argument for json format: csv_settings")
        if autogenerate_key:
            raise ValueError(
                f"'autogenerate_key' is only meaningful for 'raw' or "
                f"'plaintext' formats and would have no effect with "
                f"{format!r}. Drop it or pick a compatible format."
            )
        if json_field_paths is not None:

View on GitHub (pinned to fa2f74a464)

Solutions

1. Remove the json_field_paths argument; it is only valid for the 'json' format.

Example fix

pw.io.csv.read(path, schema=MySchema)

When it happens

Trigger: Thrown at python/pathway/io/_utils.py:358 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of pathwaycom/pathway@fa2f74a464 (2026-08-15). Data as JSON: /api/errors/c8e582b6e29ef855. Report an issue: GitHub.