From header is not correctly handled

I discovered this issue when a client's site stopped sending out emails because of a badly formed from string: there was no space between the name and the email address. This meant that the way angle brackets are handled in this module *requiring* a space broke things. The preg_match here is a better way of doing things, and I went ahead and fixed the side note you mentioned @sammuell at the bottom of #1. Here's a patch that cleans the code up, fixes my issue and probably related issues.

I added a new protected function to the class and perhaps this makes it more readable and consistent:

    // Check if the provided $name_and_address already has the one of the following formats and split them up.
    // - some name <address@example.com>
    // - "another name" <address@example.com>
    // - <address@example.com>
    $comp = array();
    if (preg_match('/^"?([^"\t\n]*)"?\s*<([^>\t\n]*)>$/', $name_and_address, $matches)) {
      $comp['name'] = trim($matches[1]);
      $comp['addr'] = trim($matches[2]);
    }
    return $comp;
  }  //  End of _smtp_get_components().

Re-rolled the last patch with some improvements, most notably such that the method returns immediately if the supplied string is already a valid email address. Reduced number of variables being used too.

OK, one more time!

I think this needs to be submitted again to be retested?

Rerolled.

Once there are some more tests committed to the module it'll be easier to test to make sure this works as intended.

The code changes here are almost identical to the issue in Drupal 8 which has already been committed #2627432: Clean up name and email address handling