addSubstitution() fails when replaced with an integer

[CyberPunkCodes]

Issue Summary

When replacing a tag with the user's ID, the email failed to send. I narrowed it down to being due to passing the user's ID as an integer.

Example:

// simulate from SQL query
$users = [
  ['id' => 0, 'name' => 'Joe Smith', 'email' => 'joesmith@example.com'],
  ['id' => 1, 'name' => 'Jane Doe', 'email' => 'janedoe@example.com']
];

$apiKey = getenv('SENDGRID_API_KEY');
$sg = new \SendGrid($apiKey);

foreach ( $users as $user )
{
  $mail = new \SendGrid\Mail();
  $from = new SendGrid\Email(FROM_NAME, FROM_EMAIL);
  $mail->setFrom($from);
  $mail->setSubject('Testing out SendGrid');
  
  $content = new \SendGrid\Content('text/plain', 'Hello, your user id is %%id%%.');
  $mail->addContent($content);
  $email = new \SendGrid\Email(null, $user['email']);
  $personalization = new \SendGrid\Personalization();
  $personalization->addTo($email);
  
  $personalization->addSubstitution("%%id%%", $user['id']);  // <-- ERROR HERE
  $mail->addPersonalization($personalization);
  $response = $sg->client->mail()->send()->post($mail);
}

I actually have my code generating batches in 500 emails per batch. The above is a simplified example of what I have.

if I replace $personalization->addSubstitution("%%id%%", $user['id']);
with
$personalization->addSubstitution("%%id%%", (string) $user['id']);
it magically works.

Alternatively, I force the user ID to a string at the top when building the $users array, but the above shows off the bug better ;)

Technical details:

• sendgrid-php Version: master
• PHP Version: 5.6

[wittfabian]

Why do you use "%%id%%" instead of "%id%"?
I am not sure, but I think the documentation provides an example with the "%id%" syntax.

[thinkingserious]

@WadeShuler,

Looks like you have been bitten by a variant of this bug: #337

I'll make sure that we cover all such cases when we push the fix. Thanks!

[thinkingserious]

This has been moved here.