On-demand Notifications addressed to multiple recipients are broken after PR #24606

[pmatseykanets]

• Laravel Version: 5.6.26
• PHP Version: 7.2
• Database Driver & Version: irrelevant to this issue

Description:

PR #24606 unfortunately broke on-demand notifications addressed to multiple recipients.

Up until this PR the following worked just fine

Notification::route('mail', ['user1@example.com', 'user2@example.com'])
    ->notify(new InvoicePaid($invoice));

After this PR the notification is being sent only to the last recipient - user2@example.com.

framework/src/Illuminate/Notifications/Channels/MailChannel.php

Line 181 in 9c684dc

protected function getRecipients($notifiable, $notification, $message)

is returning only the last item in the array because it's being overwritten here

framework/src/Illuminate/Notifications/Channels/MailChannel.php

Line 190 in 9c684dc

: [$email => $recipient];

Steps To Reproduce:

• Issue an on-demand notification addressed to multiple users as in the example above
• See in the log driver or by other means (MailHog etc) that it has been sent only to the last recipient

[laurencei]

Closing as PR with fix was merged