nextlevelbuilder/ui-ux-pro-max-skill · error · ValueError

{} must map to a non-empty action array

Error message

{} must map to a non-empty action array

What it means

Every condition key in the decision-rule object must map to a non-empty JSON array of action strings. Mapping to a scalar, an object, an empty array [], or null raises this ValueError naming the condition. Empty arrays are rejected because a condition that activates but does nothing is indistinguishable from a mistake.

Source

Thrown at src/ui-ux-pro-max/scripts/reasoning_contract.py:79

        if key in result:
            raise ValueError("duplicate decision-rule key: {}".format(key))
        result[key] = value
    return result


def parse_decision_rules(raw):
    """Parse the canonical condition -> action-array representation."""
    try:
        rules = json.loads(raw or "{}", object_pairs_hook=_object_without_duplicates)
    except json.JSONDecodeError as error:
        raise ValueError("invalid decision-rule JSON: {}".format(error)) from error
    if not isinstance(rules, dict):
        raise ValueError("decision rules must be a JSON object")
    for condition, actions in rules.items():
        if condition not in ALLOWED_CONDITIONS:
            raise ValueError("unknown decision-rule condition: {}".format(condition))
        if not isinstance(actions, list) or not actions:
            raise ValueError("{} must map to a non-empty action array".format(condition))
        for action in actions:
            _validate_action(action)
        if len(actions) != len(set(actions)):
            raise ValueError("{} contains duplicate actions".format(condition))
    return rules


def _validate_action(action):
    if not isinstance(action, str) or ":" not in action:
        raise ValueError("action must use a known prefix: {}".format(action))
    prefix, value = action.split(":", 1)
    if prefix not in ACTION_PREFIXES:
        raise ValueError("unknown decision-rule action: {}".format(action))
    if prefix in TOKEN_ACTION_PREFIXES and not TOKEN_RE.fullmatch(value):
        raise ValueError("invalid {} action value: {}".format(prefix, value))
    if prefix == "pattern" and not value.strip():
        raise ValueError("pattern action must name a pattern")
    if prefix == "mode" and value not in {"dark", "light"}:

View on GitHub (pinned to a38d04c3d5)

Solutions

1. Wrap actions in an array: "mode:dark" becomes ["mode:dark"].
2. Delete the condition key entirely if it should have no actions.
3. Ensure each element is an action string — the array shape is validated further by _validate_action.

Example fix

// before
{"if_mobile": "mode:dark", "if_luxury": []}

// after
{"if_mobile": ["mode:dark"]}

import json
rules = json.loads(raw)
for cond, actions in rules.items():
    if not isinstance(actions, list) or not actions:
        raise ValueError(f"{cond} must map to a non-empty list; got {actions!r}")

def is_non_empty_action_list(value) -> bool:
    return isinstance(value, list) and len(value) > 0 and all(isinstance(a, str) for a in value)

When it happens

Trigger: parse_decision_rules('{"if_mobile": "mode:dark"}') (string not array), '{"must_have": []}' (empty), '{"if_luxury": {"style":"luxury-gold"}}' (object), or '{"if_booking": null}'.

Common situations: Compressing a single action to a scalar for brevity; clearing a rule by emptying its array instead of deleting the key; a schema drift where actions were once objects.

Related errors

• duplicate decision-rule key: {}
• decision rules must be a JSON object
• {} contains duplicate actions
• Invalid JSON file {path}: {error}
• invalid decision-rule JSON: {}

AI-assisted analysis of nextlevelbuilder/ui-ux-pro-max-skill@a38d04c3d5 (2026-08-14). Data as JSON: /api/errors/bc66763b87201d7a. Report an issue: GitHub.