Demo seeking to understand WordPress/gutenberg#58467 (comment)

Requires Docker

To run:

./run-test.sh

This will run the same code (php a.php) in different PHP versions.

You'll see them log something like the following:

Running test from: 7.0.33
Called /a.php
Ran to completion, created class instance: A
---
Running test from: 7.4.33
Called /a.php
Ran to completion, created class instance: A
---
Running test from: 8.3.2
Called /a.php
Ran to completion, created class instance: A

If the A class is removed from a.php (e.g. rename A to A_), we'll see:

Running test from: 7.0.33
Called /b.php
Ran to completion, created class instance: A
---
Running test from: 7.4.33
Called /b.php
Ran to completion, created class instance: A
---
Running test from: 8.3.2
Called /b.php
Ran to completion, created class instance: A