PHPUnit Exception when running in Github Actions testing PHP 7.4

[udidol]

Describe the bug

We run CI tests using Github actions.
Part of our tests are PHPUnit tests, which are run using the setup-php package V2.
We test different PHP versions, and we get an Exception only on PHP 7.4:

Exception : Serialization of 'ReflectionClass' is not allowed

This is an identical issue to one also opened in Mockery: mockery/mockery#1038

Is it possible the PHP build for 7.4 used in your package is not fully up to date?

Version

• I have checked releases, and the bug exists in the latest patch version of v1 or v2.
• v2
• v1

Runners

• GitHub Hosted
• Self Hosted

Operating systems

Linux Ubuntu

PHP versions

7.4

To Reproduce

https://github.com/elementor/elementor/blob/master/.github/workflows/phpunit.yml

Expected behavior

We expect such an error to not be thrown... This seems to be a bug in early PHP 7.4 RCs.

Screenshots/Logs

Additional context

Are you willing to submit a PR?

[shivammathur]

The current PHP 7.4 version is 7.4.30.

[udidol]

@shivammathur Do you have any idea what this issue could be caused by?

[shivammathur]

I'm not sure, but this is not related to setup-php, so closing the issue.