From: Max Muermann <max@...>
Date: 2006-07-07T09:52:24+09:00
Subject: Re: debugging proposal

A few points I'd like to make on the "do we or don't we need a debugger"
debate. These are my personal opinions and not intended to upset
anybody:

1. a debugger is very helpful in understanding other people's code
(which includes frameworks like Rails). It can be valuable learning
tool, in my opinion.

2. "I don't need a debugger" or "I have never really needed a debugger"
are not valid reasons for not providing one. I don't use debuggers much,
but it's nice to know there is one, if I need it.

3. I would really like to use Ruby for most of my professional software
development. Unfortunately, IT managers are too often sold on tools,
which creates the perception that the maturity of the tools is an
indication of the value of the programming language. Now, while I
wholeheartedly disagree with that, I cannot singlehandedly change this
perception. If *I* was an IT manager in control of a project, that would
be a different story, but I earn my livelihood by being a software
consultant.

4. At the moment, my perception is that Ruby is mostly used by very
clever and very experienced people (not including myself in that). When
Ruby adoption becomes more widespread, especially in more commercial
environments (so I can actually write Ruby code for a living), there
will be inexperienced developers writing Ruby programs. My view is that
the more experienced a developer is, the less reliance they will have on
a debugger, but for all the others, a debugger is often a very valuable
tool.

5. A debugger is *not* a replacement for unit testing! (Neither are unit
tests a full replacement for a debugger, but they certainly do alleviate
the need for one)

6. A fully-featured, performant UI-based debugger will help (me, at
least) in evangelising Ruby. On two separate occasions, I have spoken to
colleagues and got feedback along the lines of "Yeah, but I couldn't
figure out why my program didn't work and it didn't have a proper
debugger, so I went back to XYZ".

7. I needed something interesting to do and this seems like a decent way
for me to understand the internals of Ruby.

Cheers,
Max


> The times that I need a debugger for my ruby code match 
> exactly to the times my ruby code is far too complicated, 
> poorly factored, or poorly tested.
> 
> Here's what debugging usually entails when I partake of it:
> 
> 1) Code breaks
> 2) mess around to find the breakage via the debugger
> 3) Fix
> 4) Goto 1
> 
> Sometimes step 2 will be the same every time because my fix 
> wasn't right, but sometimes it will be slightly different.  
> Having to repeatedly type the same (or similar) things into 
> the debugger is really, really annoying.
> 
> Unless step 2 is automatic, unit testing will beat out using 
> a debugger.  (And when it is automatic don't you have a test case
> anyways?)  With test cases I can be reasonably assured I'll 
> find a problem before I need to think about using the 
> debugger.  With just a debugger I get neither automatic 
> protection nor repeatability.
>