phacility/phabricator · error · Exception

Almanac service, device, property, network and namespace nam

Error message

Almanac service, device, property, network and namespace names may not contain multiple consecutive hyphens.

What it means

Seventh rule of AlmanacNames::validateName(): the name may not contain '--' (multiple consecutive hyphens). DNS labels disallow consecutive hyphens except in special xn-- forms, and Phabricator rejects them uniformly for all Almanac object names.

Source

Thrown at src/applications/almanac/util/AlmanacNames.php:50

          'may not have any segments containing only digits.'));
    }

    if (preg_match('/\.\./', $name)) {
      throw new Exception(
        pht(
          'Almanac service, device, property, network and namespace names '.
          'may not contain multiple consecutive periods.'));
    }

    if (preg_match('/\\.-|-\\./', $name)) {
      throw new Exception(
        pht(
          'Almanac service, device, property, network and namespace names '.
          'may not contain hyphens adjacent to periods.'));
    }

    if (preg_match('/--/', $name)) {
      throw new Exception(
        pht(
          'Almanac service, device, property, network and namespace names '.
          'may not contain multiple consecutive hyphens.'));
    }

    if (!preg_match('/^[a-z0-9].*[a-z0-9]\z/', $name)) {
      throw new Exception(
        pht(
          'Almanac service, device, property, network and namespace names '.
          'must begin and end with a letter or number.'));
    }
  }

}

View on GitHub (pinned to 5720a38cfe)

Solutions

  1. Collapse runs when sanitizing: $name = preg_replace('/-+/', '-', $name);
  2. Fix the literal name: 'web--01' -> 'web-01'.
  3. Use a single regex replacement of '/[^a-z0-9.-]+/' so whole runs become one hyphen, not several.

Example fix

// before
$name = preg_replace('/[^a-z0-9.-]/', '-', 'web__01'); // 'web--01' -> throws

// after
$name = preg_replace('/[^a-z0-9.-]+/', '-', 'web__01'); // 'web-01'
Defensive patterns

Strategy: validation

Validate before calling

if (preg_match('/--/', $name)) {
  throw new Exception('Name contains consecutive hyphens.');
}
// Prevent at construction time:
$name = preg_replace('/-+/', '-', $name);

Type guard

function hasNoConsecutiveHyphens($name) {
  return strpos($name, '--') === false;
}

Try / catch

try {
  AlmanacNames::validateName($name);
} catch (Exception $ex) {
  if (preg_match('/multiple consecutive hyphens/', $ex->getMessage())) {
    $name = preg_replace('/-+/', '-', $name); // collapse, re-run all rules
    AlmanacNames::validateName($name);
  } else {
    throw $ex;
  }
}

Prevention

When it happens

Trigger: Submitting names like 'web--01' or 'a--b', most often after a sanitizer replaces a run of bad characters with hyphens (e.g. 'web__01' or 'web / 01' becoming 'web--01').

Common situations: Naive slugification replacing each invalid character individually; joining components with '-' where one side already ends in '-'.

Related errors

AI-assisted analysis of phacility/phabricator@5720a38cfe (2026-08-21). Data as JSON: /api/errors/3890435b11fb46c5. Report an issue: GitHub.