The Dark Art of Debugging

A talk about developing the soft-skills required to be a good software debugger.

Transcript

1. The Dark Art of Debugging php[tek] 2015 - Chicago Joe (@eojthebrave) Shindelar https://joind.in/event/view /3183
2. Hi. I’m Joe Shindelar @eojthebrave
3. 5 Minutes - GO! + Bugs are inevitable + Debugging is a science + Replicate, Isolate, Understand, Fix + Practice …
4. So … where do bugs come from?
5. Software: Is a set of written instructions provided for a computer to interpret and use to accomplish a task.
6. Software: Is a set of written instructions provided for a computer to interpret and use to accomplish a task. Bugs: Are the defects that arise when those instructions are incorrectly translated.
7. “There’s a space between zero and one, between the way the machine counts and thinks and the way we count and think. When you search for explanations for software’s bugs and delays and stubborn resistance to human desires, that space is where you’ll find them.” - Scott Rosenberg -Dreaming In Code
8. The ONLY way to be a zero bug programmer is to not write any code.
9. Debugging is a practical application of both technical skills and analytical abilities
10. This presentation is not about tools. But tools play an important roll in debugging. Learn your tools. Use your tools.
11. + Replicate + Isolate + Understand + Fix
12. Ready? Fire! Aim. Give yourself 10 minutes to jump in and dirty- debug. But STOP before you go crazy.
13. STEP ONE Replicate the problem
14. It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. - Sherlock Holmes Quote -A Scandal in Bohemia
15. Replicate + Keep a log
16. Replicate + Keep a log + Get it to fail
17. Replicate + Keep a log + Get it to fail + Lay a trap
18. Replicate + Keep a log + Get it to fail + Lay a trap + Stimulate. Don’t simulate
19. Replicate + Keep a log + Get it to fail + Lay a trap + Stimulate. Don’t simulate + Automate the failure
20. Goal: Generate a list of steps
21. STEP TWO Isolate the problem
22. There is nothing more deceptive than an obvious fact. - Sherlock Holmes Quote - The Bascombe Valley Mystery
23. Isolate + Avoid easter egging
24. Isolate + Avoid easter egging + Check the plug
25. Isolate + Avoid easter egging + Check the plug + Divide & conquer
26. Isolate + Avoid easter egging + Check the plug + Divide & conquer + Change one thing at time
27. Isolate + Avoid easter egging + Check the plug + Divide & conquer + Change one thing at time + Stop thinking and look
28. Goal: Explain what is causing the problem to occur. Include details about application state, time, and inputs.
29. STEP THREE Understand the problem
30. Nothing clears up a case so much as stating it to another person. - Sherlock Holmes Quote - Silver Blaze
31. Understand + Brain games
32. Avoid confirmation bias Beware the availability heuristic
33. Understand + Brain games + Don’t assume anything. Ever
34. Understand + Brain games + Don’t assume anything. Ever + Practice tempered humility
35. Understand + Brain games + Don’t assume anything. Ever + Practice tempered humility + Read the manual
36. “Why bother, I can look it up in the Phone book.” - Einstein
37. Understand + Brain games + Don’t assume anything. Ever + Practice tempered humility + Read the manual + Ask for help
38. Goal: Explain the root cause, and how your proposed fix will solve the problem.
39. STEP FOUR Fix the problem
40. Eliminate all other factors, and the one which remains must be the truth. - Sherlock Holmes Quote - The Sign of Four
41. Fix + Don’t stop until you’re done
42. Fix + Don’t stop until you’re done + Establish causality
43. Fix + Don’t stop until you’re done + Establish causality + Test your fix
44. Goal: Close the ticket!
45. + Replicate + Isolate + Understand + Fix
46. “The greats weren't great because at birth they could paint. The greats were great cause they paint a lot.” - Macklemore
47. The Dark Art of Debugging php[tek] 2015 - Chicago Joe (@eojthebrave) Shindelar https://joind.in/event/view /3183