For the love of code: Modernizing WordPress, plugins, and themes

Presented on June 21st 2019 at WordCamp Europe, Berlin, Germany.
https://2019.europe.wordcamp.org/
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Now that WordPress has committed to a minimum requirement of PHP 7 by the end of 2019, we can all start looking at modernizing the code we maintain. Removing hacks to support old versions is easy, but how can code be improved when it just works on PHP 7? Namespaces, generators, Intl are just a few of the features introduced since PHP 5.2, not to mention scalar type declarations and all the other awesomeness that came with PHP 7. But what does it all mean, and how can you take advantage of these goodies? Join Juliette to learn to identify where to make quick fixes, when to look into refactoring, and how to make your code faster, better and more secure by using modern PHP.

Transcript

1. For the Love of Code:
   Modernizing WordPress, plugins and themes
   Juliette Reinders Folmer
   Tweet about it: @jrf_nl #ForTheLoveOfCode #WCEU
   

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2. Olivier Gobet
   

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3. PHP Supported Versions
   

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4. WordPress versus PHP
   4.2 4.3 4.4 5.0 5.1 5.2 5.3 5.4 5.5 5.6 7.0 7.1 7.2 7.3 7.4
   WP 2.0 Dec 2005
   WP 2.5 Mar 2008
   WP 3.2 July 2011 5.2.4
   ...
   WP 5.2 May 2019 5.6.20
   WP 5.? Dec 2019
   

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5. Let's
   Modernize
   All The Things!!
   

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6. But the
   code
   works
   fine on
   PHP 7...
   munozgo
   

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7. Lower Memory
   Usage
   Enhanced
   Interoperability
   New Features
   Future
   Maintainability
   Improve(d)
   Security
   Better
   Performance
   Why Modernize ?
   

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8. EricBerthe 
   kconnors 
   

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9. The fact that
   code runs on
   PHP 5.6+,
   does not make
   it PHP 5.6+
   code
   BryanHanson
   

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10. Let's Rewrite from
    Scratch!
    

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11. Let's not
     Halts Progress
     Maintaining BC will be
    much more difficult
    quicksandala
    

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12. All Code
    is Legacy Code
    as soon as it is written
    

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13. mxruben
    

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14. What Needs to be Done ?
    Fix
    Incompati-
    bilities
    Use What
    Can Already
    be Used
    Clean Up Modernize
    Implement
    Quick Fixes
    Selectively
    Refactor
    

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15. Fix Existing
    Incompatibilities
     PHP -l (lint)
     PHPCompatibility
     phan
     php7cc
     php7mar
     php-compat-info
    Seemann
    

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16. Use What Can Already
    be Used
    PHP Native features
    like:
     Autoloading
     Exceptions with
    try/catch
     instanceof
     Filter
     SPL (Stnd PHP Library)
     mysqli or PDO
     Class name based type
    declarations
     Array type declarations
    WP Polyfilled features
    like:
     Sodium
     CSPRNG (random_bytes(),
    random_int())
     Various MbString functions
     hash_equals()
     JsonSerializable interface
     spl_autoload_register()
     array_replace_recursive()
     is_iterable()
     is_countable()
    

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17. Clean Up
    (code-level)
    

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18. Remove Hacks
    and Polyfills
     version_compare()
     extension_loaded()
     class_exists()
     method_exist()
     function_exists()
     defined()
     phpversion()
     class_alias()
     PHP_VERSION_ID
     PHP_MAJOR_VERSION
     PHP_MINOR_VERSION Lilla Frerichs
    

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19. Use case-insensitive
    searches.
    

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20. Look Behind:
    Code for the now, but
    allow for the past
    Look Forward:
    Code for the lowest
    common denominator
    and allow for the future.
    

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21. Looking Forward vs Looking Behind
    if ( version_compare( phpversion(), '7.0', '>' ) ) {
    // Modern code.
    }
    // Old code.
    if ( version_compare( PHP_VERSION_ID, '59999', '<=' ) ) {
    // Back-fill for missing feature. Remove when ...
    }
    // More modern code.
    

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22. Clean Up
    (application-level)
    

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23. Use PHPUnit 5.4+ // Works with PHPUnit 3/4/5.
    class MyTest extends
    PHPUnit_Framework_TestCase { }
    // Works with PHPUnit 5.4/6/7.
    use PHPUnit\Framework\TestCase;
    class MyTest extends TestCase { }
    v Compatible with:
    8 PHP 7.2, 7.3, 7.4
    (support ends Feb 2021)
    7 PHP 7.1, 7.2, 7.3
    (support ends Feb 2020)
    6 PHP 7.0, 7.1, 7.2
    5 PHP 5.6, 7.0, 7.1
    4 PHP 5.3, 5.4, 5.5, 5.6
    

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24. Use Composer
    {
    "name": "organization/my-plugin",
    "description": "A plugin...",
    "keywords": ["wordpress"],
    "license": "GPL-2.0-or-later",
    "type": "wordpress-plugin",
    "require": {
    "php": "^5.6.20 || ^7.0",
    },
    "require-dev": {
    "humbug/php-scoper": "^0.6.0"
    },
    "autoload": {
    "classmap": [
    "src/"
    ]
    }
    }
     ... but prevent
    dependency conflicts
    

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25. Modernize
    

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26. Best Practices
     Focus on function, not
    syntax
    GaborfromHungary
    

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27. Best Practices
     Focus on function, not
    syntax
     Test Driven
    Refactoring
    GaborfromHungary
    

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28. Test Driven Refactoring
    Are there tests ? Do the tests actually
    cover the code ?
    Are the tests not
    just testing the
    "happy path" ?
    

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29. Best Practices
     Focus on function, not
    syntax
     Test Driven
    Refactoring
     Don't attempt to do
    everything at once
    GaborfromHungary
    

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30. Approaches to Modernizing
    Horizontal
    • File by file
    • Component-led
    Vertical
    • Fix by fix
    • PHP feature-led
    

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31. Best Practices
     Focus on function, not
    syntax
     Test Driven
    Refactoring
     Don't attempt to do
    everything at once
     Use the tools available
    GaborfromHungary
    

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32. Tools
    Psalm
    PHPStan
    Phan
    Exakat
    PHPModernizer
    (upcoming)
    Rector
    PHPStorm
    Inspections
    PHPMD
    (Mess Detector)
    and many more...
    

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33. Spread Operator
    Iterators &
    Generators
    Traits
    Namespaces
    Constant Scalar
    Expressions
    Quick Fixes
    Short Ternary &
    Null coalesce
    Type
    Declarations
    5.3 5.4 5.6
    5.3, 7.0, 7.4 5.0, 5.4, 7.0 – 7.2
    5.6 5.2 - 5.5
    5.3 - 7.4
    

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34. Namespaces
    Seemann
    5.3
    

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35. Logical Grouping
    of Code
    

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36. Before You Start
     Think
     Autoloading ?
    - PSR-0 (deprecated)
    - PSR-4
    - Custom
    - Classmap
    ngrigor
    

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37. What Do Namespaces Apply to ?
     Functions
     Classes
     Traits
     Interfaces
     Constants declared
    with const keyword
     Variables
     Constants declared
    with define()
     Non-PHP native
    constructs:
    - hook names
    

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38. How Does it Work ?
    Namespace
    always applied
    • Classes
    • Traits
    • Interfaces
    Fallback to global
    namespace
    • Functions
    • Constants
    Namespace
    irrelevant
    • Magic
    Constants
    

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39. FQN:
    Fully\Qualified\Name
    \Fully\Qualified\Name
    

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40. How Does it Work ?
    Namespace
    always applied
    • Classes
    • Traits
    • Interfaces
    Fallback to global
    namespace
    • Functions
    • Constants
    Namespace
    irrelevant
    • Magic
    Constants
    Must use FQN or
    use statement
    May use FQN or
    use statement
    N/A
    

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41. Namespaces
    class NSExample extends Base_Example {
    public function do_something( $input ) {
    return str_pad( $input, 10, '-', STR_PAD_LEFT );
    }
    }
    $ns_example = new NSExample();
    

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42. Namespaces
    namespace MyNS;
    class NSExample extends Base_Example {
    public function do_something( $input ) {
    return str_pad( $input, 10, '-', STR_PAD_LEFT );
    }
    }
    $ns_example = new NSExample();
    

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43. Namespaces
    namespace MyNS;
    class NSExample extends \Base_Example {
    public function do_something( $input ) {
    return \str_pad( $input, 10, '-', \STR_PAD_LEFT );
    }
    }
    $ns_example = new NSExample();
    

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44. Import Use Statements
    namespace MyNS;
    use Base\Example;
    use function str_pad;
    use const STR_PAD_LEFT;
    class NSExample extends Example {
    public function do_something( $input ) {
    return str_pad( $input, 10, '-', STR_PAD_LEFT );
    }
    }
    $ns_example = new NSExample();
    5.3
    5.6
    

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45. PHP 7 Opcode Cached Functions
     is_null()
     is_bool()
     is_long()
     is_int()
     is_integer()
     is_float()
     is_real()
     is_string()
     is_array()
     is_object()
     is_resource()
     assert()
     strlen()
     defined()
     call_user_func()
     call_user_func_array()
     boolval()
     intval()
     floatval()
     doubleval()
     strval()
     chr()
     ord()
     in_array()
     count()
     get_class()
     get_called_class()
     gettype()
     func_num_args()
     func_get_args()
     array_slice()
     sizeof()
     array_key_exists()
    7.2
    7.1
    7.4
    7.0
    

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46. Type Declarations
    5.0, 5.4, 7.0 – 7.2
    Sgarton
    

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47. Type Declarations
     5.0: Parameter Type
    Declarations
     7.0: Return Type
    Declarations
     7.0: Strict Types
     7.1: Nullable Types
    5.0 Class/Interface name based
    5.1 array
    5.2 self
    parent
    5.4 callable
    7.0 bool, int, float, string
    7.1 iterable, void
    7.2 object
    

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48. Type Declarations
    function get_tax_posts( $taxonomies = null, $limit = 5) {
    _deprecated_function( __FUNCTION__, '5.x', 'wp_get_tax_posts' );
    $taxonomies = (array) $taxonomies;
    $limit = (int) $limit;
    ...
    return $post_data;
    }
    function wp_get_tax_posts( ?array $taxonomies = null, int $limit = 5)
    : array {
    ...
    return $post_data;
    }
    return wp_get_tax_posts( $taxonomies, $limit );
    

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49. But.... There is so Much More !
    Finally
    Garbage
    Collector
    Nested
    Exceptions
    Closures
    Goto
    Late Static
    Binding
    OpCache
    Nowdocs
    

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50. And Then There's PHP 7....
    Expectations
    with assert()
    Unicode
    Escapes
    Group Use
    Declarations
    More
    Exception
    Types
    More
    Catchable
    Errors
    Uniform
    Variable
    Syntax
    Null
    Coalesce
    (equals)
    Scalar Type
    Hints & Return
    Type Hints
    

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51. And Yet More 7.x Goodies!
    Spread in
    arrays
    Multi
    catch
    Parameter
    type
    widening
    Short lists,
    keyed lists
    iterable,
    object & void
    types
    Nullable
    types
    Exceptions
    on Fatals
    Class
    constant
    visibility
    

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52. Keep
    Educating
    Yourself
    

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

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