Before using RubyMine, my debugging workflow went something like this:
Why isn’t this test passing?. It should’ve passed. Let me add a few
Kernel#putscalls to see what’s going on. Hmmm, ok, it’s still failing. I’m going to need some more output. Man, these tests take forever to run. Syntax error?!. Ugh, typo…
Debugging like this isn’t fun; especially when pairing. Fortunately, RubyMine can help. RubyMine includes a standard debugger that has minimal setup and works out of the box. I still don’t enjoy debugging, but RubyMine has made it much less painful. In this post, we’ll look at debugging in RubyMine on OS X.
Setting Breakpoints
Add or remove breakpoints with command + F8.
View existing breakpoints with command + shift + F8.
Starting the Debugger
Debug the current program with control + shift + D. This will automatically open the Debug tool window (command + 5).
Use control + D to re-run the last debug session. View recent debug sessions with control + alt/option + D.
Examining a Program
Examine variables in the Debug tool window’s variables pane.
Use command + N in the Debug tool window’s Watches pane to watch a specific variable. backspace will delete a watch.
Use alt/option + F8 to evaluate arbitrary expressions. control + space triggers autocompletion.
Instead of using the Debug tool window, examine a variable inline by placing your cursor on it and pressing command + alt/option + F8.
Stepping through a Program
Step into a method with F7. Step over a method with F8. Step out of a method with shift + F8.
Use your cursor as a temporary breakpoint with alt/option + F9. Continue your debug session with F9.
Stop #puts’ing
If you’re using an IDE, take time to learn its debugger. Don’t litter your code with Kernel#puts and friends. Instead, set a breakpoint, start the debugger, examine some objects, and slowly step through your problems.
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