redis/redis-py · error · DataError

XADD ref_policy must be one of: KEEPREF, DELREF, ACKED

Error message

XADD ref_policy must be one of: KEEPREF, DELREF, ACKED

What it means

Raised by xadd() when ref_policy is not None and not one of KEEPREF, DELREF, or ACKED. ref_policy controls how consumer-group PEL references are handled during stream trimming on XADD; only those three tokens are valid. It is a DataError.

Solutions

1. Pass ref_policy as exactly 'KEEPREF', 'DELREF', or 'ACKED' (uppercase), or leave it as None for default behavior.
2. Validate/normalize the value against the allowed set before calling xadd.

Example fix

# before
client.xadd('s', {'f': 'v'}, maxlen=100, ref_policy='delref')

# after
client.xadd('s', {'f': 'v'}, maxlen=100, ref_policy='DELREF')

VALID_REF_POLICIES = {'KEEPREF', 'DELREF', 'ACKED'}
if ref_policy is not None and ref_policy not in VALID_REF_POLICIES:
    raise ValueError(f'ref_policy must be one of {VALID_REF_POLICIES}')
client.xadd(name, fields, ref_policy=ref_policy)

from typing import Literal

def is_valid_ref_policy(p: str | None) -> bool:
    return p is None or p in {'KEEPREF', 'DELREF', 'ACKED'}

# usage
ref_policy: Literal['KEEPREF', 'DELREF', 'ACKED'] | None = None

from redis.exceptions import DataError
try:
    client.xadd(name, fields, ref_policy=ref_policy)
except DataError as e:
    if 'ref_policy' in str(e):
        client.xadd(name, fields, ref_policy=None)

When it happens

Trigger: Calling client.xadd('mystream', fields, ref_policy='keep') (wrong case), ref_policy='DELETE', or any string outside the allowed set.

Common situations: Lowercase/typo in the policy name, or forwarding an unvalidated user/config value.

Related errors

• XACKDEL ref_policy must be one of: KEEPREF, DELREF, ACKED
• IDMPAUTO and IDMP can only be used with id='*'
• Only one of ```idmpauto``` or ```idmp``` may be specified
• Only one of ```maxlen``` or ```minid``` may be specified
• XADD fields must be a non-empty dict

AI-assisted analysis of redis/redis-py@6a6b581b48 (2026-08-10). Data as JSON: /api/errors/7a81acfda2ec1a9c. Report an issue: GitHub.

Appendix: source

Thrown at redis/commands/core.py:7025

            with id='*'. The producer ID must be unique per producer and consistent across
            restarts. The idempotent ID must be unique per message and per producer.
            Shorter idempotent IDs require less memory and allow faster processing.
            Creates an IDMP map if it doesn't exist yet.

        For more information, see https://redis.io/commands/xadd
        """
        pieces: list[EncodableT] = []
        if maxlen is not None and minid is not None:
            raise DataError("Only one of ```maxlen``` or ```minid``` may be specified")

        if idmpauto is not None and idmp is not None:
            raise DataError("Only one of ```idmpauto``` or ```idmp``` may be specified")

        if (idmpauto is not None or idmp is not None) and id != "*":
            raise DataError("IDMPAUTO and IDMP can only be used with id='*'")

        if ref_policy is not None and ref_policy not in {"KEEPREF", "DELREF", "ACKED"}:
            raise DataError("XADD ref_policy must be one of: KEEPREF, DELREF, ACKED")

        if nomkstream:
            pieces.append(b"NOMKSTREAM")
        if ref_policy is not None:
            pieces.append(ref_policy)
        if idmpauto is not None:
            pieces.extend([b"IDMPAUTO", idmpauto])
        if idmp is not None:
            if not isinstance(idmp, tuple) or len(idmp) != 2:
                raise DataError(
                    "XADD idmp must be a tuple of (producer_id, idempotent_id)"
                )
            pieces.extend([b"IDMP", idmp[0], idmp[1]])
        if maxlen is not None:
            if not isinstance(maxlen, int) or maxlen < 0:
                raise DataError("XADD maxlen must be non-negative integer")
            pieces.append(b"MAXLEN")
            if approximate:

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