The Debug Dance - An Intro To Step Debugging - php[world] 2018

This talk was given at php[world] 2018.

Using `var_dump()` to debug your app has its benefits, but there are more comprehensive and efficient ways to debug those particularly illusive bugs. Enter step debugging. We'll be using Xdebug & the PhpStorm IDE to step through our PHP apps line by line and see how much more power step debugging gives us over the conventional `var_dump()` technique. We'll also touch on debugging from the command line. Learn to dance in PHP with step debugging.

Transcript

1. legacy.joind.in/24817
   @SammyK #phpworld
   Sammy Kaye Powers
   Dance
   The
   Washington, D.C. - 2018
   An Intro To
   Step Debugging in
   

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2. legacy.joind.in/24817
   @SammyK #phpworld
   CLOSER
   :)
   Get
   

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3. Thanks to Our
   Sponsors
   2018
   

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4. legacy.joind.in/24817
   @SammyK #phpworld
   Download the
   slides
   legacy.joind.in/24817
   

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5. legacy.joind.in/24817
   @SammyK #phpworld
   Does not work for
   

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6. legacy.joind.in/24817
   @SammyK #phpworld
   What is
   Debugging?
   Finding and fixing unexpected behavior in code
   

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7. So you write
   Some Code
   

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8. Does not work
   

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9. legacy.joind.in/24817
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   You could check the
   Error logs
   

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10. legacy.joind.in/24817
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    All the things
    var_dump()
    

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11. legacy.joind.in/24817
    @SammyK #phpworld
    

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12. legacy.joind.in/24817
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    OR
    

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13. legacy.joind.in/24817
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    Use a
    ‘er
    

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14. legacy.joind.in/24817
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    Kate Gregory “ I'm not saying, ‘don't
    use printf()’, [...] but
    I think it's insane to
    use printf() on day
    one of learning C++.
    [...] I would first say
    use the debugger.
    Episode 30: Stop Teaching C
    (When Teaching C++)
    

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15. legacy.joind.in/24817
    @SammyK #phpworld
    …now is the perfect time to learn
    Step Debugging
    BNEW!
    Professional
    

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16. legacy.joind.in/24817
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    Some step-debugging
    Jargon
    

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17. legacy.joind.in/24817
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    a signal that tells the debugger to pause the execution of your code
    Breakpoint
    

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18. legacy.joind.in/24817
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    run to the next breakpoint
    Resume Program
    

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19. legacy.joind.in/24817
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    advance to the next line in the same scope
    Step Over
    

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20. legacy.joind.in/24817
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    if the next line is a function call, enter the function
    Step Into
    

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21. legacy.joind.in/24817
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    run to the end of the current function
    Step Out
    

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22. legacy.joind.in/24817
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    shows the execution path to the point where the code was paused
    Frames
    I… don’t have a cool drawing for “frames”…
    

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23. legacy.joind.in/24817
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    &
    Environment
    Setup
    

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24. legacy.joind.in/24817
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25. legacy.joind.in/24817
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    https://xdebug.org/docs/remote
    Debug client (DBGp protocol)
    

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26. legacy.joind.in/24817
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    Setup
    

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27. #1
    Start listening to
    debugging connections
    

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28. #2
    Set a
    Breakpoint
    

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29. legacy.joind.in/24817
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    Done!
    

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30. legacy.joind.in/24817
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    Setup
    

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31. configured
    installed
    installed
    

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32. on
    Homebrew
    Install +
    $ brew install php
    $ pecl install xdebug
    

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33. on
    APT
    Install +
    $ add-apt-repository -y \
    ppa:ondrej/php
    $ apt-get update
    $ apt-get install php7.2-xdebug
    

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34. https://xdebug.org/docs/install
    Install +
    

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36. legacy.joind.in/24817
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    Configure
    

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37. $ php --ini
    

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38. $ php --ini
    

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39. $ sudo vi /usr/local/etc/php/
    7.2/conf.d/ext-xdebug.ini
    

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40. $ php -i | grep xdebug
    

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41. legacy.joind.in/24817
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    Start a session
    or
    CLI
    

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42. legacy.joind.in/24817
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    Query Param
    XDEBUG_SESSION_START
    

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43. legacy.joind.in/24817
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    Cookie
    XDEBUG_SESSION
    

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    @SammyK #phpworld
    

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    @SammyK #phpworld
    

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46. legacy.joind.in/24817
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    Env Variable
    export XDEBUG_CONFIG="idekey=foo"
    CLI
    

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47. legacy.joind.in/24817
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    Env Variable
    set XDEBUG_CONFIG="idekey=foo"
    CLI
    

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48. legacy.joind.in/24817
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    Don’t forget to unset
    set XDEBUG_CONFIG=
    unset XDEBUG_CONFIG
    when you’re done
    

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49. legacy.joind.in/24817
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    alias debug-on='export
    XDEBUG_CONFIG="ide_key=foo"'
    alias debug-off='unset
    XDEBUG_CONFIG'
    Bash alias
    

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50. legacy.joind.in/24817
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    Run some code!
    &
    CLI
    

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51. legacy.joind.in/24817
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    PHP’s Built-in
    Web Server
    run locally using
    

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52. legacy.joind.in/24817
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    Built right into the CLI SAPI!
    $ php -S 127.0.0.1:8888
    

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53. legacy.joind.in/24817
    @SammyK #phpworld
    

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54. legacy.joind.in/24817
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    learn?
    What did we
    

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55. legacy.joind.in/24817
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    +
    

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56. legacy.joind.in/24817
    @SammyK #phpworld
    

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57. legacy.joind.in/24817
    @SammyK #phpworld
    

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58. legacy.joind.in/24817
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    CLI
    

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59. legacy.joind.in/24817
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    Debugging In Action
    

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60. legacy.joind.in/24817
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61. legacy.joind.in/24817
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    In production
    

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62. But wait!
    * (see me after class for more info)
    

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63. Sammy Kaye Powers
    Thanks!
    /24817
    @SammyK
    SammyK.me
    Host of @PHPRoundtable
    legacy.
    

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