Eurucamp 2015: Deep Diving: How to Explore a new Codebase

As a developer, diving in a new code base is not uncommon: you’ve just been hired, you change projects, you want to help an open source project, the open source library your project depends on is buggy, etc. It’s like swimming through a underwater cave, you don’t know what treasures or monsters you’ll find, if the path is treacherous, or if it’s a true labyrinth where you’ll get lost. However, if you plan your visit, you can prepare, equip yourself, and survive to find the gem you’re looking for…

code snippet to trace the whole call graph from a piece of code https://gist.github.com/toch/82fd93ca449500d21f00

Transcript

1. Deep Diving:
   How to Explore a
   New Codebase
   Andy Spearing © 2009
   

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2. _toch
   toch
   Hi, I'm
   Christophe
   

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3. @matylda © 2011
   Intro
   

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4. @matylda © 2011
   The most
   common
   task
   

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5. continuous typing
   

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6. View Slide

7. but
   continuous reading
   Jono Witts © 2008
   

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8. Each written line
   is read
   at least 1 time
   Gavin St. Ours © 20013
   

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9. ● 300 dev days
   ● 14633 LOC
   ● 634595 Changed lines
   ● → 634595 / 14633 ~ 43 changed LOC / LOC
   

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10. For 1 final line,
    I read at least
    43 lines.
    

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11. View Slide

12. How to
    Dive
    into a project
    Stuart Hamilton © 2008
    

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13. DO NOT
    Wander
    without a plan
    Felix Esteban © 2004
    

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14. Journey
    Needs
    Plan
    Peter Southwood © 20011
    

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15. Plan
    1. Goal
    2. Map
    3. Equipment & Dive
    4. Next?
    Peter Southwood © 20011
    

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16. 1.
    Goal
    Peter Southwood © 20011
    

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17. ➔ fix a bug
    ➔ implement a feature
    ➔ write some doc
    ➔ style the code
    ➔ refactor a small piece of code
    ➔ simply use it
    

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19. http_proxy=http://127.0.0.1 \
    ruby -e "
    require 'open-uri'
    open(
    'http://google.com',
    proxy: nil
    )
    "
    

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20. ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:878:in `initialize': Connection
    refused - connect(2) (Errno::ECONNREFUSED)
    from ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:878:in `open'
    from ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:878:in `block in connect'
    from ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/timeout.rb:52:in `timeout'
    from ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:877:in `connect'
    from ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:862:in `do_start'
    from ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:851:in `start'
    from ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:313:in `open_http'
    from ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:708:in `buffer_open'
    from ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:210:in `block in open_loo
    from ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:208:in `catch'
    from ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:208:in `open_loop'
    from ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:149:in `open_uri'
    from ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:688:in `open'
    from ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:34:in `open'
    from -e:1:in `'
    

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21. 2.
    Map
    Peter Southwood © 20011
    

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22. Find the Map
    ➔ Repository URI
    ➔ Project URI
    ➔ Intro Doc: README
    

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23. Find the Map
    ● https://github.com/ruby/ruby
    ● https://bugs.ruby-lang.org/
    ● https://github.com/ruby/ruby/blob/trunk/
    README.md
    

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24. Find the Legend
    

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25. a
    Legend
    

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26. Find the Legend
    ➔ CONTRIBUTING Guideline
    

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27. Find the Legend
    ➔ CONTRIBUTING Guideline
    https://github.com/ruby/ruby/blob/trunk/
    CONTRIBUTING.md
    

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28. Find the Legend
    ➔ CONTRIBUTING Guideline
    https://github.com/ruby/ruby/blob/trunk/
    CONTRIBUTING.md
    

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29. Find the Legend
    ➔ CONTRIBUTING Guideline
    ➔ Directory Structure
    

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30. Find the Legend
    ➔ CONTRIBUTING Guideline
    ➔ Directory Structure
    

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31. Find the Legend
    ➔ CONTRIBUTING Guideline
    ➔ Directory Structure
    ➔ Talk to other contributors, maintainers
    

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32. Find the Legend
    ➔ CONTRIBUTING Guideline
    ➔ Directory Structure
    ➔ Talk to other contributors, maintainers
    ➔ Participate to the dev meeting
    

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33. If blocked?
    ➔ ASK!
    

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34. Boris Dimitrov © 20009
    3.
    Equipment
    & Dive
    

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35. Get a Toolbelt
    ➔ Pick an Editor
    

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36. xkcd
    

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37. Get a Toolbelt
    ➔ Pick an Editor
    ➔ Bundle
    

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38. $ cd GitLab
    $ bundle viz
    

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39. $ cd GitLab
    $ bundle viz
    

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40. $ cd GitLab
    $ bundle viz
    

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41. Get a Toolbelt
    ➔ Pick an Editor
    ➔ Bundle
    ➔ Run Tests
    

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42. Get a Toolbelt
    ➔ Pick an Editor
    ➔ Bundle
    ➔ Run Tests
    ➔ Others
    

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43. Get a Toolbelt
    ➔ ST3
    ➔ Apply a Patch & Use it
    ➔ MRI WIKI DeveloperHowto
    ➔ Sign up to Ruby Redmine
    

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44. Use your Toolbelt
    ➔ Run the App & Use it
    

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45. http_proxy=http://127.0.0.1 \
    ruby -e "
    require 'open-uri'
    open(
    'http://google.com',
    proxy: nil
    )
    "
    

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46. Use your Toolbelt
    ➔ Run the App & Use it
    ➔ Read the Code
    

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47. $ wc -l *.rb
    1001 common.rb
    257 ftp.rb
    1676 generic.rb
    106 http.rb
    22 https.rb
    260 ldap.rb
    20 ldaps.rb
    280 mailto.rb
    3622 total
    open-uri
    

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48. ➔ Find proxy management
    ➔ Understand how open_http works
    ➔ Spot the bug
    URI
    

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49. ➔ Trace the Calls
    Dive into URI
    

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50. def get_call_graph_on
    scope = {}
    trace = TracePoint.new(:call, :line) do |tp|
    case tp.event
    when :call then puts "#{tp.path}:#{tp.lineno} #{tp.defined_class}::#{tp.method_id} called from " \
    "#{scope[:path]}:#{scope[:lineno]} #{scope[:class]}::#{scope[:method_id]}"
    when :line then scope = {
    event: :line,
    lineno: tp.lineno,
    path: tp.path,
    class: tp.defined_class,
    method_id: tp.method_id
    }
    end
    end
    trace.enable
    yield
    trace.disable
    end
    

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51. require 'open-uri'
    get_call_graph_on do
    open(
    'http://google.com',
    proxy: nil
    )
    end
    

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52. ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:28 Kernel::open
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:746 #::parse
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:209 URI::Parser::parse
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:120 URI::Parser::split
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:659 #::scheme_list
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:659 #::scheme_list
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/http.rb:83 URI::HTTP::initialize
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:173 URI::Generic::initialize
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:342 URI::Generic::set_scheme
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:523 URI::Generic::set_userinfo
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:556 URI::Generic::split_userinfo
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:617 URI::Generic::set_host
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:709 URI::Generic::set_port
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:842 URI::Generic::set_path
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:907 URI::Generic::set_query
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:970 URI::Generic::set_opaque
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:779 URI::Generic::set_registry
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:1013 URI::Generic::set_fragment
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:36 URI::Generic::default_port
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:29 #::defaul
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:36 URI::Generic::default_port
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:29 #::defaul
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:709 URI::Generic::set_port
    

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53. ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:28 Kernel::open
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:746 #::parse
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:209 URI::Parser::parse
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:120 URI::Parser::split
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:659 #::scheme_list
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:659 #::scheme_list
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/http.rb:83 URI::HTTP::initialize
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:173 URI::Generic::initialize
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:342 URI::Generic::set_scheme
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:523 URI::Generic::set_userinfo
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:556 URI::Generic::split_userinfo
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:617 URI::Generic::set_host
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:709 URI::Generic::set_port
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:842 URI::Generic::set_path
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:907 URI::Generic::set_query
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:970 URI::Generic::set_opaque
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:779 URI::Generic::set_registry
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:1013 URI::Generic::set_fragment
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:36 URI::Generic::default_port
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:29 #::defaul
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:36 URI::Generic::default_port
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:29 #::defaul
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:709 URI::Generic::set_port
    

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54. ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:659 #::scheme_list
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:659 #::scheme_list
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/http.rb:83 URI::HTTP::initialize
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:173 URI::Generic::initialize
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:342 URI::Generic::set_scheme
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:523 URI::Generic::set_userinfo
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:556 URI::Generic::split_userinfo
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:617 URI::Generic::set_host
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:709 URI::Generic::set_port
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:842 URI::Generic::set_path
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:907 URI::Generic::set_query
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:970 URI::Generic::set_opaque
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:779 URI::Generic::set_registry
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:1013 URI::Generic::set_fragment
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:36 URI::Generic::default_port
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:29 #::defaul
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:36 URI::Generic::default_port
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:29 #::defaul
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:709 URI::Generic::set_port
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:687 OpenURI::OpenRead::open
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:130 #::open_uri
    

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55. ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:29 #::defaul
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:709 URI::Generic::set_port
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:687 OpenURI::OpenRead::open
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:130 #::open_uri
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:120 #::scan_open_opt
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:111 #::check_options
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:166 #::open_loop
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:376 OpenURI::Buffer::initialize
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:707 URI::HTTP::buffer_open
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:253 #::open_http
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:571 URI::Generic::userinfo
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:3
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:183 MonitorMixin::mon_enter
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:1118 #::find_u
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:889 #::suffixe
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/specification.rb:1168 #unresolved_deps
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:194 MonitorMixin::mon_exit
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:244 MonitorMixin::mon_check_owner
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:3
    

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56. ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:707 URI::HTTP::buffer_open
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:253 #::open_http
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:571 URI::Generic::userinfo
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:3
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:183 MonitorMixin::mon_enter
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:1118 #::find_u
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:889 #::suffixe
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/specification.rb:1168 #unresolved_deps
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:194 MonitorMixin::mon_exit
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:244 MonitorMixin::mon_check_owner
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:3
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:183 MonitorMixin::mon_enter
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:1118 #::find_u
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:889 #::suffixe
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/specification.rb:1168 #unresolved_deps
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:194 MonitorMixin::mon_exit
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:244 MonitorMixin::mon_check_owner
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:3
    

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57. ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:707 URI::HTTP::buffer_open
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/open-uri.rb:253 #::open_http
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:571 URI::Generic::userinfo
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:3
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:183 MonitorMixin::mon_enter
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:1118 #::find_u
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:889 #::suffixe
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/specification.rb:1168 #unresolved_deps
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:194 MonitorMixin::mon_exit
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:244 MonitorMixin::mon_check_owner
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:3
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:183 MonitorMixin::mon_enter
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:1118 #::find_u
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:889 #::suffixe
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/specification.rb:1168 #unresolved_deps
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:194 MonitorMixin::mon_exit
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:244 MonitorMixin::mon_check_owner
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:3
    

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58. ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:244 MonitorMixin::mon_check_owner
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:3
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:183 MonitorMixin::mon_enter
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:1118 #::find_u
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:889 #::suffixe
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/specification.rb:1168 #Specification>::unresolved_deps
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:194 MonitorMixin::mon_exit
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:244 MonitorMixin::mon_check_owner
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:3
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:183 MonitorMixin::mon_enter
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:1118 #::find_u
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:889 #::suffixe
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/specification.rb:1168 #Specification>::unresolved_deps
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:194 MonitorMixin::mon_exit
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:244 MonitorMixin::mon_check_owner
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:3
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:183 MonitorMixin::mon_enter
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:1118 #::find_u
    

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59. ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:194 MonitorMixin::mon_exit
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/monitor.rb:244 MonitorMixin::mon_check_owner
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:660 URI::Generic::hostname
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/http.rb:95 URI::HTTP::request_uri
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:1442 URI::Generic::path_query
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:608 #::new
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:632 Net::HTTP::initialize
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:993 #::proxy_class
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:847 Net::HTTP::start
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:861 Net::HTTP::do_start
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:867 Net::HTTP::connect
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:1012 Net::HTTP::proxy?
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/net/http.rb:1026 Net::HTTP::proxy_uri
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:990 Kernel::URI
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:746 #::parse
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:209 URI::Parser::parse
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:120 URI::Parser::split
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:659 #::scheme_list
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/common.rb:659 #::scheme_list
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/http.rb:83 URI::HTTP::initialize
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:173 URI::Generic::initialize
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:342 URI::Generic::set_scheme
    ~/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/uri/generic.rb:523 URI::Generic::set_userinfo
    

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60. http = klass.new(
    target_host,
    target_port
    )
    

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61. ➔ Trace the Calls
    ➔ Search the Source
    Dive into URI
    

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62. Search the Source
    $ grep -nr "open_http".
    ./open-uri.rb:253: def OpenURI.open_http(buf, target, proxy, option
    ./open-uri.rb:708: OpenURI.open_http(buf, self, proxy, options)
    ./open-uri.rb:717: OpenURI.open_http(buf, self, proxy, option
    

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63. Search the Source
    $ grep -rn "class HTTP " .
    ./net/http.rb:384: class HTTP < Protocol
    ./uri/http.rb:22: class HTTP < Generic
    

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64. Search the Source
    $ EDITOR=subl \
    bundle open gitlab_omniauth-ldap
    

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65. ➔ Trace the Calls
    ➔ Search the Source
    ➔ Get Context with a Test
    Dive into URI
    

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66. Get Context with a Test
    context "without params['markdown_img']" do
    it "returns an error" do
    get_call_graph_on do
    post :upload_image, id: project.to_param, format: :json
    end
    expect(response.status).to eq(422)
    end
    end
    

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67. Use your Toolbelt
    ➔ Run the App & Use it
    ➔ Read the Code
    ➔ Edit the Code
    

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68. http = proxy ?
    klass.new(target_host, target_port) :
    klass.new(target_host, target_port, nil)
    

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69. Use your Toolbelt
    ➔ Run the App & Use it
    ➔ Read & Edit the Code
    ➔ Report a bug
    ➔ Submit a contribution
    

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70. View Slide

71. If blocked?
    ➔ ASK!
    

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72. 4.
    Next?
    Peter Southwood © 20011
    

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73. How long?
    ➔ Keep it reasonable at first
    ➔ From ½ to 1 day
    

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74. Find Next Goal
    ➔ Fix a bug
    ➔ Develop a feature
    ➔ Run Static Analysis Tools
    ➔ Review a PullRequest
    

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75. Iterate
    ➔ :)
    Jean-Marc Kuffer © 2007
    

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76. If blocked?
    ➔ ASK!
    

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77. Outro
    1. Goal
    2. Map
    3. Equipment & Dive
    

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78. ?
    _toch
    toch
    

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