Migrating from PHP 5.6 to 8.0: Handling Deprecated Features and Compatibility Issues
I'm relatively new to this, so bear with me. I'm integrating two systems and Recently started working on migrating our MVP from PHP 5.6 to 8.0, and I’m running into compatibility issues that weren't obvious during initial testing... One major area of concern is the deprecation of certain features and functions that our existing code relies on. For instance, the use of the `mysql_*` functions is widespread in our legacy codebase. I’ve been replacing these with `mysqli` and `PDO` methods, but I still see some warnings related to incompatible type hints in my function signatures, especially those that return arrays. Here’s a snippet where the return type is causing issues: ```php function getUsers(): array { $result = mysqli_query($this->connection, 'SELECT * FROM users'); if ($result) { return mysqli_fetch_all($result, MYSQLI_ASSOC); } return []; } ``` The `getUsers` function throws a warning if the `mysqli_query` fails and subsequently returns `null` instead of an empty array. Another thing I noticed during development is the `create_function()` usage throughout our code. I’ve replaced these with anonymous functions, but I’m not sure if this is the best practice moving forward, as there are still instances where variables remain accessible outside their intended scope, which I suspect could lead to complications. In addition, I’m trying to enhance performance by switching to named parameters in method calls, which I believe may improve code readability and maintenance. However, I worry about backward compatibility issues with older libraries that don’t support this feature. Lastly, our unit tests are failing since they were written with PHPUnit 6, and upgrading to PHPUnit 9 has introduced stricter type checks. For example, one of our tests now fails with: ``` TypeError: Return value of Tests\Unit\UserTest::testUserCreation must be of the type void, none returned ``` How can I resolve these issues effectively while ensuring our new code is robust and maintainable? Any insights on best practices or strategies for handling these migrations would be greatly appreciated! My team is using Php for this CLI tool. Has anyone else encountered this?