What causes "Condition references a rule which does not exist!" in phacility/phabricator?

Edit the rule and remove or re-point the 'references rule' condition to an existing rule.

phacility/phabricator · error · HeraldInvalidConditionException

Condition references a rule which does not exist!

Error message

Condition references a rule which does not exist!

What it means

For CONDITION_RULE / CONDITION_NOT_RULE ('linked/other rule' conditions), the condition value is the PHID of another Herald rule; the adapter looks it up with $engine->getRule($condition_value). A null result — the referenced rule does not exist or was not loaded into the engine — throws HeraldInvalidConditionException. Most commonly the referenced rule was deleted while this rule still points at it.

Source

Thrown at src/applications/herald/adapter/HeraldAdapter.php:593

              pht('First regular expression is invalid!'));
          }
          if ($key_matches) {
            $value_matches = @preg_match($value_regexp, $value);
            if ($value_matches === false) {
              throw new HeraldInvalidConditionException(
                pht('Second regular expression is invalid!'));
            }
            if ($value_matches) {
              return true;
            }
          }
        }
        return false;
      case self::CONDITION_RULE:
      case self::CONDITION_NOT_RULE:
        $rule = $engine->getRule($condition_value);
        if (!$rule) {
          throw new HeraldInvalidConditionException(
            pht('Condition references a rule which does not exist!'));
        }

        $is_not = ($condition_type == self::CONDITION_NOT_RULE);
        $result = $engine->doesRuleMatch($rule, $this);
        if ($is_not) {
          $result = !$result;
        }
        return $result;
      case self::CONDITION_HAS_BIT:
        return (($condition_value & $field_value) === (int)$condition_value);
      case self::CONDITION_NOT_BIT:
        return (($condition_value & $field_value) !== (int)$condition_value);
      default:
        throw new HeraldInvalidConditionException(
          pht("Unknown condition '%s'.", $condition_type));
    }
  }

View on GitHub (pinned to 5720a38cfe)

Solutions

Edit the rule and remove or re-point the 'references rule' condition to an existing rule.
If you must delete a rule, first check whether other rules' conditions reference its PHID.
For bulk hygiene, query herald_condition for values equal to deleted rule PHIDs and clean them up.

Defensive patterns

Strategy: validation

Validate before calling

// Before saving a rule that references another rule:
$ref = id(new HeraldRuleQuery())
  ->setViewer(PhabricatorUser::getOmnipotentUser())
  ->withPHIDs(array($referenced_rule_phid))
  ->executeOne();
if (!$ref) {
  // do not save the condition - the referenced rule does not exist
}

Prevention

Before deleting a Herald rule, search other rules for conditions referencing its PHID.
After imports/migrations, verify rule-reference conditions still resolve.

When it happens

Trigger: Rule A has a 'rule' condition referencing rule B (by PHID); rule B is deleted or disabled beyond engine visibility; next evaluation of rule A fails with this exception and A stops applying.

Common situations: Deleting rules that are still referenced by other rules; moving a rule's content into a new rule and deleting the old one; migrations where referenced PHIDs do not exist in the target instance.

Related errors

AI-assisted analysis of phacility/phabricator@5720a38cfe (2026-08-21). Data as JSON: /api/errors/e5cbcafc7e342664. Report an issue: GitHub.