Tackling the ElePHPant in the Room

Presented on June 22nd 2023 at the Brussels PHP meetup, Brussels, Belgium.
https://www.meetup.com/brusselsphp/events/293335070/
---------------------------------------------------------------
Preparing for compatibility with a new PHP version... for some of us it's something to spend some time on every few years or so, for others, like those of us managing open source projects, it's a yearly chore which can take months of work.
PHPCompatibility is one of the tools which can help you find PHP cross-version incompatibilities.
In this talk, Juliette will give an introduction on how PHPCompatibility can help you, but more importantly, will take you behind the scenes and give you some insight into the enormous impact the plethora of syntax enhancements in PHP itself has on tooling like PHPCompatibility.
Fasten your seatbelt and prepare for a wild ride!

Transcript

1. Tackling the ElePHPant
   in the Room
   Juliette Reinders Folmer Tweet about it: @jrf_nl #BrusselsPHP
   Rolf Dobberstein
   

   View Slide

2. Update vs Upgrade
   

   View Slide

3. Making Your Application Compatible
   Tests
   

   View Slide

4. Your Tests
   Are
   Not Good Enough
   

   View Slide

5. Making Your Application Compatible
   Tests
   PHPCS /
   CS-Fixer
   PHPStan /
   Psalm
   Rector
   PHP
   Compatibility
   

   View Slide

6. PHPCompatibility ▪ External standard for
   PHP_CodeSniffer
   ▪ Started in 2010
   by Wim Godden
   ▪ Currently 155 sniffs
   

   View Slide

7. PHPCompatibility ▪ Deprecated: warning
   ▪ Removed: error
   ▪ New: error
   Modular error codes for
   optimal configurability
   

   View Slide

8. Installing PHPCompatibility
   composer config
   allow-plugins.dealerdirect/phpcodesniffer-composer-installer true
   composer require –dev
   phpcompatibility/php-compatibility:"^10.0"
   

   View Slide

9. Running PHPCompatibility
   [vendor/bin/]phpcs –ps .
   --standard=PHPCompatibility
   --runtime-set testVersion 7.3-
   [--extensions=php]
   [--report=full,source]
   

   View Slide

10. TestVersion ?
    Fixed testVersion 7.3
    Range testVersion 7.3-8.1
    Up to testVersion -8.1
    Minimum
    and up
    testVersion 7.3-
    Barbary Dougherty
    

    View Slide

11. Demo ?
    

    View Slide

12. PHPCompatibilityAll
    PHPCompatibility
    PHPCompatibility
    Symfony
    PHPCompatibility
    Paragonie
    PHPCompatibility
    PasswordCompat
    PHPCompatibility
    Joomla
    PHPCompatibility
    WP
    

    View Slide

13. PHP
    and
    PHPCompatibility
    luxstorm
    

    View Slide

14. PHP PHPCompatibility
    

    View Slide

15. PHP 8.2 Partially Supported Callables Deprecation
    "self::method"
    "parent::method"
    "static::method"
    ["self", "method"]
    ["parent", "method"]
    ["static", "method"]
    ["Foo", "Bar::method"]
    [new Foo, "Bar::method"]
    call_user_func($callback, $param);
    $callback()
    

    View Slide

16. Fixed of not ?
    class Foo {
    public function bar() {
    // Do something conditionally if a child class
    // has implemented a certain method.
    if (is_callable('static::methodName')) {
    call_user_func('static::methodName');
    static::methodName();
    }
    }
    }
    

    View Slide

17. PHP PHPCompatibility
    

    View Slide

18. A Look Behind
    The Curtain
    Marina Bridger
    

    View Slide

19. PHPCompatibility
    PHP Tokenizer
    PHP_CodeSniffer
    PHPCompatibility
    Composer PHPCS Plugin
    

    View Slide

20. PHPCompatibility 10.0+
    PHP Tokenizer
    PHP_CodeSniffer
    PHPCSUtils
    PHPCompatibility
    Composer PHPCS Plugin
    

    View Slide

21. Limitations
    ▪ Context: current file
    only
    ▪ No access to runtime
    values (variables)
    Stefan Parnet
    

    View Slide

22. Getting Ready: "Normal" Project
    Ensure
    dependencies are
    compatible
    Make own code
    compatible
    

    View Slide

23. Getting Ready: PHP_CodeSniffer
    Adjust existing
    sniffs to allow for
    new PHP version
    Backfill/Polyfill
    new syntaxes
    Ensure
    dependencies are
    compatible
    Make own code
    compatible
    

    View Slide

24. Getting Ready: PHPCompatibility
    Detect new
    incompatibilities
    Adjust existing
    sniffs to allow for
    new PHP version
    Ensure
    dependencies are
    compatible
    Make own code
    compatible
    

    View Slide

25. New syntaxes/tokenizer changes
    PHP 5.5 5.6 7.0 7.1 7.2 7.3 7.4 8.0 8.1 8.2
    New
    operators
    2 3 1 1 1
    New
    constructs
    4 1 6 1 1 1 9 4 2
    Other
    relevant
    changes
    1 1 1 4 2 2 2 5 4 3
    

    View Slide

26. Impact of New Syntaxes [1]
    // Deprecated PHP 7.4, removed PHP 8.0.
    is_real($var);
    // False positive prevention:
    $this->is_real($var);
    MyClass::is_real($var);
    MyNamespace\is_real($var);
    // PHP 8.0+ nullsafe object operator…
    $obj?->is_real($var);
    

    View Slide

27. Impact of New Syntaxes [2]
    class Foo {
    // PHP 7.4+ Typed property.
    public string $propA;
    // PHP 7.0+ Scalar type declaration,
    // PHP 7.1+ nullable type.
    public function bar(?int $param) {}
    // Oops...
    public function __construct(public ?int $propB) {}
    }
    

    View Slide

28. Impact of New Syntaxes [3]
    // PHP 8.1+ new hash algorithm.
    hash_init('xxh64');
    // Argh...!
    hash_init(
    flags: HASH_HMAC,
    key: 'mysecret',
    algo: 'xxh64',
    );
    

    View Slide

29. What's Next ?
    ▪ PHPCompatibility 10.0
    expected soon(ish)
    ▪ New contributors
    (and sponsors!)
    welcome!
    Ben Kerckx
    

    View Slide

30. Thanks!
    Any
    questions ?
    Slides: https://speakerdeck.com/jrf
    Feedback: https://joind.in/talk/dafa1
    @jrf_nl @jrfnl
    @jrf_nl@phpc.social
    

    View Slide