If you have an invalid API key or anything else that may cause a server error when using the API, in sendTemplate(), the $result returned is actually an instance of GuzzleHTTP/ServerException, not an array, which is not allowed in PHP 8.1.
It's a bit weird, as in Mailchimp's transactional API in vendor/mailchimp/transactional/lib/Configuration.php, in the post() function the sendTemplate() is using, it's designed in a way that it either returns the response body as an array, or if there's a RequestException, it returns the exception, so we cannot catch the RequestException in our code either...
// send request
try {
$client = $this->getRequestClient();
$response = $client->request('POST', $postUrl, $options);
$resp = $response->getBody();
$contentType = $response->getHeaderLine('content-type');
if (strpos($contentType, 'application/json') !== false) {
return json_decode($resp);
}
return $resp;
} catch (RequestException $e) {
return $e;
}
To resolve, we can either change the sendTemplate() function to return "mixed", or check if the result is an exception and log an error. I've done the latter, and will just add my code, but this may need some more thought.
This relates to issue: https://www.drupal.org/project/mailchimp_transactional/issues/3279838 🐛 TypeError: Drupal\mailchimp_transactional\API::send(): Return value must be of type array, ConnectException returned Needs review
Closed: duplicate
1.0
Code
The issue particularly affects sites running on PHP version 8.1.0 or later.
Closing this as https://www.drupal.org/project/mailchimp_transactional/issues/3279838 🐛 TypeError: Drupal\mailchimp_transactional\API::send(): Return value must be of type array, ConnectException returned Needs review basically is the same problem, and at the moment, patch #7 fixes the problem.