Bringing Old Legacy Apps To PHP 7 and Beyond - ZendCon 2016

Most developers don't get the luxury of working on a greenfield project using a web framework of their choice. Often times we find ourselves inheriting a legacy codebase or a web app written years ago on a now-defunct web framework. The initial temptation might be, "I'll just rewrite all this in x framework." But hold on my framework friend, a rewrite is costly and is rarely the correct answer. We'll discuss strategies to give that legacy codebase a complete makeover in PHP 7 with incremental changes that keep the business running while improving security, stability, and maintainability of the codebase.

Transcript

1. Bringing Old Legacy Apps To
   October 19th, 2016
   Sammy Kaye Powers
   @SammyK
   PHP 7 & Beyond
   

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2. Codebase
   @SammyK #zendcon2016 joind.in/talk/6d127
   

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3. View Slide

4. I’ll just rewrite
   this in
   ____________!
   @SammyK #zendcon2016 joind.in/talk/6d127
   

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5. I’ll just rewrite
   this in
   ____________!
   @SammyK #zendcon2016 joind.in/talk/6d127
   

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6. I’ll just rewrite
   this in
   ____________!
   Laravel
   @SammyK #zendcon2016 joind.in/talk/6d127
   

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7. I’ll just rewrite
   this in
   ____________!
   @SammyK #zendcon2016 joind.in/talk/6d127
   

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8. rewrite from
   scratch?
   Why not
   @SammyK #zendcon2016 joind.in/talk/6d127
   

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9. Functionality
   Existing Codebase Fancy-pants rewrite
   

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10. Functionality
    Existing Codebase Fancy-pants rewrite
    

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11. Functionality
    Existing Codebase Fancy-pants rewrite
    

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12. Functionality
    Existing Codebase Fancy-pants rewrite
    

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13. Functionality
    Existing Codebase Fancy-pants rewrite
    

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14. Refactoring
    Martin Fowler
    http://martinfowler.com/books/refactoring.html
    

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15. “Legacy”
    /leɡəsē/
    • Requires an EOL version of PHP
    • No automated tests
    • Has outdated dependencies
    • No autoloading
    • No sign of “single responsibility”
    

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17. “Legacy”
    We’ll assume
    …means any code that
    can be improved
    @SammyK #zendcon2016 joind.in/talk/6d127
    (at least for this talk)
    

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18. Expectations
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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19. elePHPant
    How to eat an
    

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20. ZERO
    Step
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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21. Around
    Poke
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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22. Around
    Poke
    • Composer &/or autoloading?
    • Documentation? (Look for hidden docs!)
    • Framework/Dependencies? (How out-dated?)
    • How is database layer implemented?
    • How is config handled?
    • How are front-end assets handled?
    • Are there tests?
    • Production env (PHP version)
    

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23. Analysis
    Static
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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24. phploc
    

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25. phploc
    

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26. phpcpd
    

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27. Consider the
    Stakeholders
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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28. Consider the Stakeholders
    I’ll need 80
    hours to
    refactor the
    user auth & ACL
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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29. Consider the Stakeholders
    • Most critical security holes
    • Most critical bugs
    • Most critical features
    • Use data from static analysis
    Make a plan
    

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30. ONE
    Step
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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31. Environment
    Get it running on your local
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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32. From Docker to
    production
    Chris Tankersley
    @SammyK #zendcon2016 joind.in/talk/6d127
    Today @ 5:15PM in Artist 3
    

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33. Git
    Get with
    master
    original
    local-config
    

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34. 5.(wat)
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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35. Fix all the errors
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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36. View Slide

37. TWO
    Step
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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38. 7.0
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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39. 7.0
    ✓Performance
    increase
    PHP 7
    features
    ✓
    

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40. 7.0
    

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41. BC
    is totes amaze
    

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42. PHP 7.0 enlightenment
    The path to
    7.0
    5.6
    

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43. PHP 7.0 enlightenment
    The path to
    7.0
    5.5
    

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44. PHP 7.0 enlightenment
    The path to
    7.0
    5.4
    

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45. PHP 7.0 enlightenment
    The path to
    7.0
    >= 5.3
    

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46. THREE
    Step
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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47. Fix all the PHP 7 errors
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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48. PHP 7.0
    Quick tricks to refactor to
    (in order of ease)
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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49. PHP 7.0 “Gotchas”
    ASP and script PHP
    tags removed
    <% %>
    <%= %>
    
    

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50. PHP 7.0 “Gotchas”
    removed
    php://input
    $HTTP_RAW_POST_DATA
    instead read from
    $HTTP_RAW_POST_DATA =
    file_get_contents('php://input');
    

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51. PHP 7.0 “Gotchas”
    PHP-4-style constructors
    deprecated
    class foo {
    function foo() {}
    }
    

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52. PHP 7.0 “Gotchas”
    PHP-4-style constructors
    deprecated
    class foo {
    function __construct() {}
    }
    

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53. PHP 7.0 “Gotchas”
    Some
    functions
    got the ax
    ereg*
    functions
    

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54. PHP 7.0 “Gotchas”
    “There’s a shim for that!”
    

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55. PHP 7.0 “Gotchas”
    “There’s a shim for that!”
    ereg* functions
    bbrala/php7-ereg-shim
    eregi($pattern, $sub, &$match)
    preg_match('/'.$pattern.'/i', $sub, $match)
    

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56. PHP 7.0 “Gotchas”
    Another
    one bites
    the dust
    ext/mysql
    functions
    

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57. PHP 7.0 “Gotchas”
    “There’s a shim for that!”
    ext/mysql functions
    dshafik/php7-mysql-shim
    

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58. PHP 7.0 “Gotchas”
    Caveats though…
    ext/mysql functions
    dshafik/php7-mysql-shim
    $con = mysql_connect(…);
    $connected = is_resource($con);
    

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59. PHP 7.0 “Gotchas”
    Another bird
    with the
    PHP 7.0 stone
    ext/mssql
    functions
    instead use
    sqlsrv_*(), odbc_*(), PDO
    

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60. PHP 7.0 “Gotchas”
    A few others
    for the
    chopping
    block
    Some
    ext/mcrypt
    functions,
    et. al.
    

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61. PHP 7.0 “Gotchas”
    Scalar Type
    Declarations
    New reserved keywords:
    string, int, bool, float
    

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62. View Slide

63. PHP 7.0 “Gotchas”
    Uniform
    Variable Syntax
    Change in evaluating indirect expressions
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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64. PHP 7.0 “Gotchas”
    Uniform Variable Syntax
    $$foo['bar']['baz']
    

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65. PHP 7.0 “Gotchas”
    Uniform Variable Syntax
    $foo = ['bar' =>
    ['baz' => ‘apple']];
    $apple = 'PHP 5.x I see...';
    var_dump($$foo['bar']['baz']);
    string(16) "PHP 5.x I see..."
    5.x
    

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66. PHP 7.0 “Gotchas”
    Uniform Variable Syntax
    Notice: Array to string conversion in /
    foo.php on line 6
    Notice: Undefined variable: Array in /
    foo.php on line 6
    7.x
    

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67. PHP 7.0 “Gotchas”
    Uniform Variable Syntax
    $$foo['bar']['baz']
    5.x
    

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68. PHP 7.0 “Gotchas”
    Uniform Variable Syntax
    $$foo['bar']['baz']
    5.x
    

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69. PHP 7.0 “Gotchas”
    Uniform Variable Syntax
    ${'apple'}
    5.x
    

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70. PHP 7.0 “Gotchas”
    Uniform Variable Syntax
    $apple
    5.x
    string(16) "PHP 5.x I see..."
    

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71. PHP 7.0 “Gotchas”
    Uniform Variable Syntax
    $$foo['bar']['baz']
    7.x
    

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72. PHP 7.0 “Gotchas”
    Uniform Variable Syntax
    $$foo['bar']['baz']
    7.x
    

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73. PHP 7.0 “Gotchas”
    Uniform Variable Syntax
    ${['bar' => ['baz' => ‘apple']}
    [‘bar’]['baz']
    7.x
    

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74. PHP 7.0 “Gotchas”
    Uniform Variable Syntax
    ${‘Array’}[‘bar’]['baz']
    7.x
    

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75. PHP 7.0 “Gotchas”
    Uniform Variable Syntax
    $$foo['bar']['baz']
    7.x
    

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76. PHP 7.0 “Gotchas”
    Uniform Variable Syntax
    ${$foo[‘bar’]['baz']}
    7.x
    

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77. PHP 7.0 “Gotchas”
    $$foo['bar']['baz']
    ${$foo['bar']['baz']}
    ($$foo)['bar']['baz']
    5.x
    7.x
    Uniform Variable Syntax
    

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78. FOUR
    Step
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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79. Code!
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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80. Tests
    TESTS
    Tests
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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81. PHPUnit?
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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82. Acceptance
    Tests
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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83. Codeception
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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84. Behavior-driven
    testing framework
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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85. Composer +
    Autoloading
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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86. @SammyK #zendcon2016 joind.in/talk/6d127
    

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87. Feature
    (User Story)
    

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88. Scenario
    

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89. @SammyK #zendcon2016 joind.in/talk/6d127
    

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90. Scenario
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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91. View Slide

92. FIVE
    Step
    “The Refactoring Loop”
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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93. refactorLoop:
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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94. Start
    small
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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95. View Slide

96. Make sure there’s a test
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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97. @SammyK #zendcon2016 joind.in/talk/6d127
    Refactor
    

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98. Run your tests
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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99. goto refactorLoop;
    @SammyK #zendcon2016 joind.in/talk/6d127
    

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100. lets you refactor like a
     BEAST
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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101. PHPUnit
     Don’t forget about
     

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102. PHP 7.0
     Features
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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103. random_int()
     random_bytes()
     PHP 7.0 Features
     CSPRNG!!
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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104. JOURNEY
     MY
     CENTER
     TO
     THE
     OF
     #ShamelessPlug
     Tomorrow @ 11:30am
     in Festival 2
     

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105. PHP 7.0 Features
     Scalar Type
     Declarations
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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106. PHP 7.0 Features
     Scalar Type Declarations
     function foo(string $name,

     int $age,

     bool $isGreat,

     float $income)

     { /* */ }
     

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107. PHP 7.0 Features
     Scalar Type Declarations
     function foo(string $name,

     int $age,

     bool $isGreat,

     float $income)

     { /* */ }
     

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108. 99.99999999999942
     I got
     problems but
     float $income
     NEVER USE
     FLOATS
     FOR MONEY!
     

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109. PHP 7.0 Features
     Return type
     declarations
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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110. PHP 7.0 Features
     Return type declarations
     /**

     * @return Collection

     */

     public function foo()

     {

     }
     

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111. PHP 7.0 Features
     /**

     * @return Collection

     */

     public function foo()

     {

     }
     Return type declarations
     

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112. PHP 7.0 Features
     public function foo(): Collection

     {

     }
     Return type declarations
     

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113. PHP 7.0 Features
     Null coalesce
     operator
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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114. PHP 7.0 Features
     $bar = isset($_GET[‘foo’]) ?
     $_GET[‘foo’] : null;
     Null coalesce operator
     $bar = $_GET[‘foo’] ?? null;
     

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115. PHP 7.0 Features
     Insane speed
     improvements
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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116. And
     beyond?
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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117. PHP 7.1
     Considering
     RC3
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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118. PHP 7.1 considerations
     deprecated
     ext/mcrypt
     Soon to be...
     

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119. Void return
     types
     PHP 7.1 considerations
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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120. public function foo(): void

     {

     }
     Void return types
     PHP 7.1 considerations
     

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121. Nullable
     types
     PHP 7.1 considerations
     @SammyK #zendcon2016 joind.in/talk/6d127
     (kinda like union types for null)
     

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122. Nullable types
     function foo(string $name)

     { /* */ }
     PHP 7.1 considerations
     

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123. Nullable types
     function foo(?string $name)

     { /* */ }
     PHP 7.1 considerations
     

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124. Nullable types
     function foo(string $name = null)

     { /* */ }
     foo();
     PHP 7.1 considerations
     

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125. Nullable types
     foo();
     function foo(?string $name)

     { /* */ }
     foo(null);
     PHP 7.1 considerations
     

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126. Nullable types
     function foo(): ?string {
     return null;
     }
     PHP 7.1 considerations
     

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127. Class constant
     visibility
     PHP 7.1 considerations
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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128. Class constant visibility
     class Foo {

     public const FOO = 0;
     protected const BAR = 1;
     private const BAZ = 2;
     }
     PHP 7.1 considerations
     

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129. `iterable`
     pseudo-type
     PHP 7.1 considerations
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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130. `iterable` pseudo-type
     function foo(iterable $a)

     { /* */ }
     PHP 7.1 considerations
     $b = [];
     foo($b);
     class C implements Iterator {}
     $b = new C;
     foo($b);
     

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131. `iterable` pseudo-type
     PHP 7.1 considerations
     class D implements IteratorAggregate {}
     foo(new D);
     Traversable
     Or instance of
     

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132. Some tools
     I like
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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133. vlucas/phpdotenv
     .env
     No peeking!
     No peeking!
     

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134. Some tools I like
     pimple/pimple
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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135. Some tools I like
     monolog/monolog
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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136. Some tools I like
     nikic/fast-route
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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137. Some tools I like
     illuminate/database
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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138. Some tools I like
     symfony/console
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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139. Create a PHP
     application without a
     framework
     https://github.com/PatrickLouys/no-framework-tutorial
     Patrick Louys
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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140. Big-picture
     Refactoring
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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141. Constant refactoring
     is the key to managing
     legacy
     codebases
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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142. Constant refactoring
     is the key to managing
     legacy
     codebases
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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143. Resources
     013: TDD & BDD In PHP
     Soon: Acceptance
     Testing with Behat
     017: Modernizing Legacy
     Codebases in PHP
     November 3rd @ 12:00PM CDT
     

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144. Modernizing Legacy
     Applications in PHP
     https://leanpub.com/mlaphp
     Paul M. Jones
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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145. Refactoring
     Martin Fowler
     http://martinfowler.com/books/refactoring.html
     @SammyK #zendcon2016 joind.in/talk/6d127
     

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146. Takk!
     (thanks)
     @SammyK
     SammyK.me
     Host of @PHPRoundtable
     @ChiPHPUG
     West Coast Swing
     Hire me! :)
     /talk/6d127
     

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