[5.8] Use a library for email validation

[phroggyy]

Summary

This PR aims to resolve #13215 and similar problems users may experience when trying to send emails with non-ascii characters. The current version of Laravel is dependent on Swiftmailer ^6.0, which added support for RFC5630 email addresses. However, the email validation rule in the current version of Laravel relies on PHP's built-in email validation, which is based on the 1982 RFC822 according to the official documentation.

Thus, the aim here is just to bring the framework's validation inline with what we support in terms of SMTP sending (through Swiftmailer).

Breaking Changes

This PR will result in a breaking change – emails that (incorrectly) were considered invalid will now be considered valid. e.g hej@bär.se. Any applications that have been relying on the strict RFC822 validation will thus need updating (e.g users that run their own antiquated email servers).

Impact: Low

Notes

• Note that the included dependency is already required by Swiftmailer.
• Using new EmailValidator rather than $this->container->make() was a conscious decision to reduce backwards compatibility issues, as $this->container is only defined if the validator factory is used

[staudenmeir]

Why do we need egulias/email-validator as a separate dependency when it comes with Swift Mailer?

[phroggyy]

@staudenmeir because any library should declare its own dependencies. If Swiftmailer stops depending on that package, we need to make sure we're still pulling it in.

[X-Coder264]

@phroggyy You must add the new dependency to the illuminate/validation package composer.json too (as the validation component can be used outside of a full Laravel framework app).

[phroggyy]

Good one @X-Coder264. Done.

[taylorotwell]

Thanks

[coquer]

@taylorotwell do you think it is a good idea to fork this to 5.4? there is so many big projects that can't be upgraded to php 7 and still stuck in 5.4.x and would benefit from this a ton

[driesvints]

@jycr753 heya sorry but 5.4 is EOL and won't be getting any more updates. It's important that you upgrade to the latest versions to get bug and security fixes as well as make use of the latest features.

[ymotorwala]

This causes https://stackoverflow.com/questions/58725526/validation-of-an-email-address-in-laravel

Laravel 7 seems to have a workaround of using 'email:rfc' but laravel 6 does not.
I guess Laravel 6 too should have this workaround as it is LTS

[driesvints]

@ymotorwala Laravel v6 isn't maintained anymore. Please upgrade to Laravel 9.