fix(email): prevent Proton SMTP From header folding (#11400)

bootstrap/helpers/notifications.php

@@ -6,6 +6,7 @@ use Illuminate\Mail\Message;
 use Illuminate\Notifications\Messages\MailMessage;
 use Illuminate\Support\Facades\Mail;
 use Symfony\Component\Mime\Address;
+use Symfony\Component\Mime\Email;
 
 function is_transactional_emails_enabled(): bool
 {
@@ -45,6 +46,32 @@ function mail_from_formatted(object $settings): string
     return mail_from_address($settings)->toString();
 }
 
+function mail_from_email(Email $email, object $settings): Email
+{
+    $email->from(mail_from_address($settings));
+    prevent_mail_from_header_folding($email, $settings);
+
+    return $email;
+}
+
+function mail_from_message(Message $message, object $settings): Message
+{
+    $identity = mail_from_identity($settings);
+    $message->from($identity['address'], $identity['name']);
+    prevent_mail_from_header_folding($message->getSymfonyMessage(), $settings);
+
+    return $message;
+}
+
+function prevent_mail_from_header_folding(Email $email, object $settings): void
+{
+    if (strtolower(trim((string) ($settings->smtp_host ?? ''))) !== 'smtp.protonmail.ch') {
+        return;
+    }
+
+    $email->getHeaders()->get('From')?->setMaxLineLength(998);
+}
+
 function send_internal_notification(string $message): void
 {
     try {
@@ -61,14 +88,11 @@ function send_user_an_email(MailMessage $mail, string $email, ?string $cc = null
     if (blank($type)) {
         throw new Exception('No email settings found.');
     }
-    $from = mail_from_identity($settings);
-
     if ($cc) {
         Mail::send(
             [],
             [],
-            fn (Message $message) => $message
-                ->from($from['address'], $from['name'])
+            fn (Message $message) => mail_from_message($message, $settings)
                 ->to($email)
                 ->replyTo($email)
                 ->cc($cc)
@@ -79,8 +103,7 @@ function send_user_an_email(MailMessage $mail, string $email, ?string $cc = null
         Mail::send(
             [],
             [],
-            fn (Message $message) => $message
-                ->from($from['address'], $from['name'])
+            fn (Message $message) => mail_from_message($message, $settings)
                 ->to($email)
                 ->subject($mail->subject)
                 ->html((string) $mail->render())