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Why I use a debugger

blog.pnkfx.org

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Re: Why I use a debugger

#41

Post by foxfluff »

kotxig wrote: post #38
cool-RR wrote: post #30

I feel like many of the commenters here haven't experienced enough corporate environments. I love using a debugger for open-source projects I work on and web apps I used to do for clients, but when you're working for a big company it's usually difficult to impossible to attach a debugger. Almost all of them have such convoluted setups that you'd need to use remote debugging, which is difficult to configure. You can b…

The reason debuggers are often hard to use in these environments is because people who don't routinely use debuggers to do their job do not see the value of them, and so organizations do not prioritize your ability to do this. The tone of the comments here in general is sceptical of the use of debuggers and this is exactly why you can't use them in some FAANG's - it's not a popular belief even though to anyone who do…

I use vim but I don't think it's a superpower and it's rare for me to need its advanced features. I doubt vim is giving me any edge over $other_editor, I just happen to find it ergonomic and a good fit for me. Maybe I don't use it well enough?

Likewise, I don't feel debuggers are a superpower. It's rare for them to "save the day". It's just a tool that I sometimes go for. The last time I remember using a debugger was a few months ago to figure out a memory leak. hexdump would've worked just as well.

Re: Why I use a debugger

#42

Post by willcipriano »

foxfluff wrote: post #35
willcipriano wrote: post #26

Earlier quoted context omitted.

Whatever works for you man, but if you spend two plus weeks on a bug in a if statement that would've been obvious at a first glance with a debugger, I'm not going to feel like we are contributing at the same level. It's like we are tasked with digging a ditch together and you want to use a tea spoon instead of a shovel.

> a bug in a if statement that would've been obvious at a first glance with a debugger If you already knew which if statement to look at, it's irrelevant whether you use a debugger or printf(). Actually, it becomes even less relevant when you have thousands of dynamically allocated objects running the same statement but only one of them goes wonky and you only know which one it is later at runtime. In the end you end…

> If you already knew which if statement to look at, it's irrelevant whether you use a debugger or printf().

That's exactly when it matters, when you don't know where the problem is. You have a big ball of spaghetti business logic and a customer object that is passing through it. At some point the customers total balance is screwed up. You can:

- Read a lot of code and guess where that happens and set a printf or two, if you find it great, if not read more and set more printf's

- Set a watcher on the customers total, and review the logic each place it is modified and ensure it is correct before moving on

The first way you have to build the project over and over again, and you might miss something. The second way guarantees you find the problem eventually, and you only end up building a few times. If we have a project with a 5 minute build time, and a really thorny problem this can be a massive difference.

That isn't to mention the value of doing this in concert with the creation of a unit test that recreates the bug to further reduce the bugfix feedback loop.

Re: Why I use a debugger

#43

Post by School-Cotton »

cool-RR wrote: post #30

I feel like many of the commenters here haven't experienced enough corporate environments. I love using a debugger for open-source projects I work on and web apps I used to do for clients, but when you're working for a big company it's usually difficult to impossible to attach a debugger. Almost all of them have such convoluted setups that you'd need to use remote debugging, which is difficult to configure. You can b…

I worked for Facebook and Amazon and used a debugger at both places regularly, on several layers of the stack.

Re: Why I use a debugger

#45

Post by rocgf »

foxfluff wrote: post #37
rocgf wrote: post #36

Earlier quoted context omitted.

Allow me to doubt that this is possible on a regular basis. Anyone can get bouts of error-free code. It happens on a regular basis that I write dozens of lines of code and everything just works, without any debugging. However, it's not just the code you write, there are also bugs in code that someone wrote 5 years ago. Or a bug in a library that you have no idea about. A lot of times, these can be solved with a debug…

"Doesn't need debugger" isn't same as "error-free code." You can solve bugs by thinking about / reading code. I'd say that's the way I solve the vast majority of my bugs. Also "using a debugger" and "debugging" are not synonymous.

Scratching your left ear with your right hand doesn't mean that pelicans can't fly.

Or, in other words, you just said a bunch of seemingly-relevant keywords, but without actually making any sense. Your comment looks a lot like what GPT-3 might have to say about this discussion.

Re: Why I use a debugger

#47

Post by kotxig »

I am surprised to find in these comments that using the debugger routinely and by default isn't a popular idea. I couldn't do my job as well as I do without having the reflex to use the debugger. I shouldn't be surprised though, the last time I watched a coworker roll his face on the keyboard trying to debug something the conversation went something like:

  - Me: Just use the debugger...
  - Him: But it's hard and annoying to use the debugger
  - Me: It's hard and annoying not having the skills or reflex to use the debugger by default
  - Him: ... ok I agree ... continues rolling face on the keyboard and add print statements everywhere
I think much of the sentiment in these comments is sounding like "that's not how I work so I will defend myself". Just learn how to use your debugger and integrate it into your work flow. You don't need a special IDE to use a debugger in most languages if that's the perceived problem.

Re: Why I use a debugger

#48

Post by School-Cotton »

morelisp wrote: post #19
the-alt-one wrote: post #13

How quickly do you guys whip out the debugger when you encounter a bug? I often can figure it out by reading the code (I'm the quickest jump-to-source in the wild west!) quicker than I can from inserting print stmts or hooking up a debugger. I've also decided that I dislike having my IDE be my debugger, I prefer having an entirely separate UI for that. Maybe this is because I use Emacs and DAP mode and gdb is quite p…

I suspect this will be controversial, but I read TPOP at a young age and I think it still summarizes my overall view. The quote from the article continues: Blind probing with a debugger is not likely to be productive. It is more helpful to use the debugger to discover the state of the program when it fails, then think about how the failure could have happened. Debuggers can be arcane and difficult programs, and espec…

> The goal of most IDEs seems to be first help with a debugger / executing code/tests, second help with writing code

We must not be using the same IDEs. To me “IDE functionality” is almost synonymous with “code navigation”: jump to definition, find references, etc., which are purely “code reading” features.

Re: Why I use a debugger

#49

Post by whizzter »

foxfluff wrote: post #35
willcipriano wrote: post #26

Earlier quoted context omitted.

Whatever works for you man, but if you spend two plus weeks on a bug in a if statement that would've been obvious at a first glance with a debugger, I'm not going to feel like we are contributing at the same level. It's like we are tasked with digging a ditch together and you want to use a tea spoon instead of a shovel.

> a bug in a if statement that would've been obvious at a first glance with a debugger If you already knew which if statement to look at, it's irrelevant whether you use a debugger or printf(). Actually, it becomes even less relevant when you have thousands of dynamically allocated objects running the same statement but only one of them goes wonky and you only know which one it is later at runtime. In the end you end…

That's exactly when a GOOD debugger becomes useful, if you can get an hint at what's wrong you can often (if needed and the fault wasn't caught by the debugger) put in a good conditional expression for the breakpoint and only break once it fails, yet if every input looks fine and your code isn't a mutating mess you can set a previous line as the next statement and re-step what happened to create the error condition for the particular object.

Adding traces (probably over several iterations to narrow down things), rebuilding, rerunning and inspecting those traces would've probably taken multiples of the time to build and run everything up to the point of failure.

Re: Why I use a debugger

#50

Post by nicoburns »

rocgf wrote: post #36
mettamage wrote: post #28

Earlier quoted context omitted.

There are programmers that rarely need debuggers because they deeply think about the state of the program at every line of execution. I am not one of them but it is an amazing sight to see. And if they then use a debugger, they are in and out in a jiffy (usually).

Allow me to doubt that this is possible on a regular basis. Anyone can get bouts of error-free code. It happens on a regular basis that I write dozens of lines of code and everything just works, without any debugging. However, it's not just the code you write, there are also bugs in code that someone wrote 5 years ago. Or a bug in a library that you have no idea about. A lot of times, these can be solved with a debug…

> A lot of times, these can be solved with a debugger and a few WTFs or with a week of trying to understand every line of code, it's states and the transition between those states.

In my experience the vast majority of those cases can be solved with quick search of the Github issue tracker to find someone else who has already debugged the issue, followed by an upgrade of the library to a newer version that's already been released to fix the issue, or if you're unlucky manually applying a patch.

Of course, that person's probably used a debugger to solve the issue. And sometimes you need to be that person. But IMO if you're using libraries that regular require you to pull out a debugger, then maybe you ought to be using better libraries.

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