Asking questions - Speaker Deck

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On asking questions @fglc2

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Sooner or later, trouble will strike

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Sooner or later, trouble will strike Don’t Panic

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Isolate the problem • Narrow down ‘It’s not working’ to something more speciﬁc • “My data isn’t being saved in the database”: is it because of the form, the controller or the model? • Can you recreate the problem in the rails console? • Error messages: which line of code is responsible?

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Decode your exceptions • The exception tells you what went wrong and where (check just before too) • The stack trace gives you more information on where in your program you are

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NoMethodError: undefined method `length' for nil:NilClass # ./app/models/compiled_outfit.rb:310:in `block in results_to_candidate_outfits' # ./app/models/compiled_outfit.rb:301:in `collect' # ./app/models/compiled_outfit.rb:301:in `results_to_candidate_outfits' # ./app/models/compiled_outfit.rb:211:in `candidate_outfits' # ./app/models/compiled_outfit.rb:182:in `outfits' # ./app/models/compiled_outfit.rb:423:in `outfits_for_garment' # ./spec/models/compiled_outfit_spec.rb:106:in `block (5 levels) in ' # ./spec/spec_helper.rb:142:in `block (2 levels) in ' # -e:1:in `'

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Gather information • Use your log ﬁles: development.log records all requests, parameters, SQL queries • Use the debugger to interact with code as it runs • Log extra information def do_thing(parameter) Rails.logger.info "do_thing called with #{parameter}” ... end

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Rubber ducking • Walk through each line of your program • Explain to an (imaginary) rubber duck what that line is, what the values of variables are, what all the method calls it does are • Forces you to think about your code and any assumptions made (question them!)

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I’m still stuck

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Help the reader recreate your problem

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Simplify the problem • Try to recreate a small self contained example • Remove non pertinent bits • Make sure your simpliﬁcation hasn’t removed the problem

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Banish “it doesn’t work” • What did it do? • What did you expect it to do (& why?)

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Context is king • Describe what you were attempting - don’t lead with a wall of code • Include error messages, stack traces (and how they related to the code you post) • Describe your investigations & attempts to ﬁx this • Provide information such as ruby or rails versions, OS

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Where to ask? • Stack Overﬂow (and other sites in the Stack Exchange family) • Mailing Lists, forums • IRC channels • codebar or other face-to-face events

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Further reading • http://www.catb.org/esr/faqs/smart-questions.html • http://stackoverﬂow.com/help/how-to-ask • http://stackoverﬂow.com/help/mcve