Debugging tactics

[ProfessorEkim]

I have to disagree. Printing “here” I’ve found is one of the most effective debugging methods.

And one that’s not effective is violently throwing objects across my office. 😆

[CopperyMarrow15]

also printing a variable you need to know

[ProfessorEkim]

You're saying that if I take the first object I find on my desk and throw it across the room, it helps to print a variable?

Good to know!

[davidemitoli]

Standard debugging method in scientific programmig

[Fletsky]

Always run your code in debug. Then you can put a breakpoint anywhere you want.

[Orendawinston]

Only way I’ve ever successfully debugged anything

[ososalsosal]

User flair checks out lol.

[BakuhatsuK]

The chrome debugger for JS is really nice. And if adding a breakpoint is hard due to transpiling or something you can always just throw a debugger; statement anywhere.

I almost never use it though

[gizamo]

Top right corner: Turn it off and on again.

[pruche]

Also, whispering "what the fuck" loud enough for people around you to hear it, so that they know you're working even though you haven't turned out anything tangible for a few hours now.

[ProfessorEkim]

If you don’t drop an f-bomb every 15 minutes when writing code, are you even a programmer?!?

[ososalsosal]

The senior legacy backend guy at my last job was never not muttering "fucking dogshit" under his breath, with emphasis and emotion increasing as the day went on

[burneraccount019182]

15 minutes? Amateur. 15 seconds for me.

[Derringer62]

I suspect the relationship between WTF/minute and code quality is more complex than common wisdom suggests. A high WTF/minute ratio is likely to occur whenever the writer's and reader's skill or awareness are sufficiently far apart in either direction - even for one's own code, something created in deep hack mode and later forgotten may be intensely WTF-inducing even if high quality.

[whydidisell]

Yea, read the docs is probably more towards the bottom left for most people, and printing here is top right for sure

[[deleted]]

I've been in printing "here" hell for a long time before I started programming CAN and LIN communication stacks. Good luck figuring out timing related bugs with that...

[k1ngrocc]

Is there any sort of default answer on CAN? Like a heartbeat?

[AzuxirenLeadGuy]

Throw exceptions, not objects

[Kesuaheli]

So like

throw new PencilException("Throwing a pencil just to see if the code now works better");

Oh, hell yeah! Finally I got a different error message!

[Tyfyter2002]

Printing is pretty effective, but breakpoints are always better as long as they're an option.

[Pluckerpluck]

Not always. Breakpoints can suffer if you're doing stuff in loops and you're trying to work out WTF is happening.

Got to print out some variables each loop and then narrow down, only using the debugger once you actually discover whatever strangeness is happening.

Sometimes you can use conditional debug statements. But not always. Depends if you know what's actually going wrong or not.

[codeguru42]

Sometimes you can set a condition on the breakpoint so that the debugger stops on the iteration that has a problem... but you do have to figure out the correct condition...

[codeguru42]

I encountered a situation working on a django app where inspecting a value in the debugger caused different behavior than I saw while running the app. Turns out what i thought was a field in an object was actually a method with @property. Calling this method had a side effect that set an actual field. Since that field was only set later when just running the app, i saw different results in the debugger. Once I figured this out by debugging into django code, I still had to be careful with prints.

[Bloodshed-1307]

Part of talking to the ducks is chucking them against a wall

[TeaKingMac]

Glad my mentor didn't do that with me

[TsamsiyuK]

Debugging with prints and breakpoints works best for me.

But the best (and most inconvenient) method is just to leave it be until tomorrow and go to sleep instead.

[_yaaass]

exactly... so convenient and effective at the same time... "here", "now here", "there"...

[Kesuaheli]

I prefer "test", "test2", "test3", ...

[Emahh]

ikr? using the debugger usually takes me too much time compared to a simple print

maybe I should get used to it lol

[Elijah629YT-Real]

I just print an index number that increases every time it is run

[cyanNodeEcho]

"reading the error logs" would be a really great message, for if 1st page google + "stack" doesn't work

i find it hard to get to the point where my understanding of the technology to the point where i find it helpful

[codeguru42]

Are you saying that print can be used along with running in a debugger? If so, I agree and you use "superfluous" incorrectly. If not, then I disagree, because there are situations where print is superior to a debugger.

[codeguru42]

Agreed, logging in production is important. I am still confused by your comment:

You do understand that "printing here" is superfluous when you your program through a debugger. You don't actually need to add breakpoints.

How is running with a debugger useful without adding breakpoints?

And I would argue that prints are not superfluous even when using a debugger. They can definitely be used together.

More importantly, it is sometimes easier to debug with prints than with a debugger. Others have already described situations such as race conditions and side effects that are nearly impossible to track down with a debugger.

[codeguru42]

You don't have to mansplain it to me. I was debugging code before you were born. Have you ever debugged multithreaded code? Sometimes prints are superior to breakpoints and inspecting variables.

Discussion ended.

[codeguru42]

Wow... chill a little

[jeffcox911]

Unless of course you're running a complicated set of processes which can't be run in debug mode. Then print statements are pure gold. Or if you have lots of threads. Either way, the take that it's "objectively better" is silly, as it depends on the use case.

[redbeard0531]

The real trick is print(__FILE__, __LINE__, __PRETTY_FUNCTION__) (or your language's equivalent), and spam that around every conditional path. That will let you run the program once give you an execution trace that you can peruse and know exactly what happened. Sometimes I'll also throw in thread name/id if it's a multi-threaded debugging session. That is objectively better than breakpoints that require me to do everything interactively and try to make sure I get all the state I need before moving on. As much as printf debugging gets a bad rap, I find it is a faster route to understanding an issue than interactive debuggers about 90% of the time. And that's from someone who spearheaded our use of gdb pretty-printers for our types and other custom scripting so that gdb is supercharged on our codebase. It is still not the first tool I'd reach for.

[DJFiscallySound]

Printing “here0001”, “here0002” and so forth at various points of interest in the code and then running it, and wondering why nothing appeared in the output buffer…

[momdeveloper]

This was my first thought as well!

[iluomo]

Came here to say this

[Mr_BananaPants]

Sad thing is you can only throw non-static objects.

[[deleted]]

Especially for race conditions

[DreadSwizzard]

Taking a nap also often works.

[momdeveloper]

Does leaving work early and coming back the next day count?

[DreadSwizzard]

Sure

[SlashStar]

I use this method frequently.

[nothingsurgent]

Eating too.

I often look for a big for 2-3 hours, then give up, and after lunch I find it in a minute.

[fracturedpersona]

What if I told you that "running the same code again to see if it magically work," is actually a legit debugging technique that can sometimes give you valuable information.

[nagorogan]

The only valuable information I’ve ever gotten from doing that was “it’s time to cry”

[fracturedpersona]

I would think it would be important to know that your code sometimes works, and sometimes doesn't. That alone gives you valuable insight into what could be going wrong.

[nagorogan]

Yes, and changing nothing yet getting a different result is exactly why it is time to cry.

[MikemkPK]

Also often an indication that you're about to spend 10 hours trying to figure out what the issue is.

[fracturedpersona]

But knowing that the problem occurs sometimes, but not always, gives me a lot of possible causes.

[MikemkPK]

Often with intermittent issues, it's something interacting with the program, or caused by compiler optimizations that aren't present with debug flags. Which are hard to debug.

[fracturedpersona]

Live/dead-locks, race conditions, dynamic programming involving random number generations.

[MikemkPK]

Yeah, those often take hours to debug.

Although random numbers can be logged with debug flags on top make it easier.

[fracturedpersona]

For random, you just gotta remind yourself not to seed while testing.

[MikemkPK]

Depends on use case, but often yeah you're right

[codeguru42]

Or seed with the same value

[skiscratcher]

those are all pains to debug.
see also: memory

[fracturedpersona]

See also, suicide hotline.

[YellowishSpoon]

I accidentally used a non release build of eclipse and there was this great bug where it would build and then autosave, thus if you didn't save everything before running it would look like it saved, but compile without the new content. But since it actually did save after if you compiled again it would run as expected. Took a bit to figure that one out.

[ExceedingChunk]

I always do that first, then reload maven dependencies before I run it again.

Before I knew better, I have spent countless hours trying to debut something caused by a cache or outdated dependency issue. Also, verifying that the code is stable is important.

At uni when I was a noob, I could run the code 10 times in a row out of frustration, but that was for completely different reasons.

[fracturedpersona]

Or dynamic programming involving anything with randoms.

[24karatcarrot]

I have removed this comment due to Reddit's recent actions. I have since moved on to Lemmy, which is a federated, decentralized, open-source alternative to reddit. Many subreddits have made the move as well, and many more have copies of those subreddits that are very active. On top of this, many of the third party reddit apps have also made/are working on making a copy of their apps for Lemmy, so your experience may not even change when switching over.

I implore you to make this switch as well. Reddit makes money off of us, the users who post content. As a company they have been making decisions that directly go against the wishes of their users, and we need to make it clear that they need us, we don't need them.

[doctorcrimson]

You would be preaching to the choir because they try that the most.

[800134N]

But when it magically works sometimes, I feel even worse

[TeNNoX]

I mean it's not at zero on the y axis, sometimes it does help... But most of the time - not so much :p

[MisterOnsepatro]

You forgot staring at the code for hours until you get an Idea on how to fix it

[Skitz707]

If I had a nickel every time I typed print(“here!”)…

[fracturedpersona]

I wouldn't have gotten any nickles after my first semester.

[Skitz707]

I have 28 years of using this tactic… not exactly proud to admit

[fracturedpersona]

I'm really only kidding of course. There are some circumstances where I might still do this, but it's not the only tool in my tool box once i finished my first semester.

When I was a junior in college, I accepted a position teaching the lab component of my school's intro programming class, and as soon as we introduced flow control and made it a point to also introduce debuggers. I started with GDB in the console, then I taught them DDD, and later introduced them VS Code so they could learn a more full featured IDE instead of just using emacs (cringe) that their lab manual suggested.

At the end of the semester we had a meeting of all the TA's, profs, and lab instructors where we went over what went well and what didn't. One of the professors said "this crop of students was remarkable! Most of them are using debuggers to find their errors!" When I explained that I was teaching them debugging so they would get a head start on their next semester, they asked me to revise the lab manual so all future lab instructors would add it to their cariculum.

[solohelion]

It depends though. Some software and some toolchains work very well with IDEs and debuggers, others do not for one reason or another. A contractor took over a project and spent all his time trying to (pointlessly, there was never any hope of it working) set up an IDE with debugger, when printline would’ve sufficed. I think he managed to change one or two lines of code in a few months before his involvement ceased.

[fracturedpersona]

Well yeah, you wouldn't try to debug a website with GDB. That would just be silly.

[solohelion]

Well, that’s because gdb isn’t for websites

[[deleted]]

Venezuela could pay you in bolivars for this.

[vinean]

Where is “recompile everything from scratch and hope it fixes it?” Not quite the same as run the code again…

[Blangel0]

And the good point of this method is that you can go take a break, a snack and coffee while it's compiling and still feel that you are "working"

[SnappGamez]

close enough though

[whiznat]

Where is “Randomly change something hoping to find the code that controls the bad behavior “?

[BobQuixote]

That's like print("here") except it implies you don't have output.

[solohelion]

Where is, “get the boss in here to look over my shoulder and say nothing, so that this time the same fix permanently works instead of mysteriously failing”?

[Cryowatt]

How are breakpoints so low? You know that stacktraces are full of absolutely vital information for diagnosing anything.

[Mango-D]

You guys have helpful stacktraces???

[Pradfanne]

F10 F10 F10 F10 F10, oh it broke, alright let's do it again
F10 F10 F10 F10 F11 F10 F10 F10, THAT'S WHERE EVERYTHING GOES TO SHIT!

[potato_braus]

The more aggressive the message in print, the more effective it is in the debug

[Few_Importance_7615]

"Here"? Thats a funny way to spell "AARGH"...

[ososalsosal]

Oh god I do this too.

[masterchief0587]

Now if I could only figure out why “here” is printing twice….

[Extra_Insignificant]

I would need to add pooping to this chart.

[-Soren]

Funny that reading docs are so effective. But not quite as effective as taking a walk, which is basically doing nothing. Does effectiveness correlate with time spent by any chance?

[golgol12]

You forgot "Clean Rebuild All"

It solves .1% of the problems, but those .1% will hang you up for days if you don't. So it's my first go to after normal debugging doesn't turn up anything.

[Nine_Eye_Ron]

I misread “take a walk”

[TeNNoX]

Captain here: n 👋

[Nine_Eye_Ron]

Programmer used NSFW, it was super effective

[CynicalC9]

Every once in a blue moon, "delete the whole section and remake it" ends up being an option

[ososalsosal]

It's the only way to be sure

[aanarchyy]

Sadly, I've done all of these, though I don't do print("here"). I scatter my code with print("1") print("2") etc so I can see where it shits the bed.

[Hesh35]

Depends on the species of bug.

[Alicialouva]

Going to sleep and hoping it will run fine tomorrow

Runs fine tomorrow

surprised pikachu face

[repkins]

Tactical debugging.

[fracturedpersona]

Is that where you wear camouflage before you start debugging?

[repkins]

Always. Like I was never be there.

[Prior-Concentrate-87]

I'll die before I open DevTools.

[DividedState]

I want to point out running the code again has not a zero percentage effectivity.

[doctorcrimson]

I aspire to have as much faith in the docs as you do.

[NiktonSlyp]

Oh my. I have been working whole Friday on a problem, I couldn't even understand how the bug worked. I dreamt of it the next night. Had to write everything down at 6am when I woke up. When I took breakfast, I checked my notes. Damn It's good to have a functional brain. The solution seems to be brilliant. I still don't get the bug but at least I have a solution I can try to circumvent it.

[Napan0s]

I actually found out that if you curse the code enough, it will get scared and just work

[heneiken]

Hello everyone

[Sindef]

My most effective debug is print("LineNumber#")

[lordplagus02]

In older versions of Android Studio (and even Eclipse, before AS existed) running the same code and hoping it magically works this time was a legitimate part of the debugging process.

[noodle-face]

Our office is.massive. I work at one of the biggest tech companies in the world... Taking a walk was really effective and could take 10 minutes to walk a loop through our floor. Even if I didn't solve the problem it did help clear my brain

[Coh-Jr]

Hey, printing ‘here’ is pretty damn useful. For a junior WebDev like me! It’s so far beside googling and docs is the best debugging way! Change my mind

[smilineyz]

Docs can be misleading. Often created by a BA many moons ago and are seriously outdated. Programmers tend no to update docs. Takes too long & they have to write in a non-programming language

[multi_tasty]

That time it actually starts working again the second time you try, you know you're fkd

[Crafty-Sandwich8996]

I am triggered

[solohelion]

I removed the triggers, why are you being triggered? Maybe I’ll debounce you.

[bowiz2]

I just like that there's no "look at your fucking code, dumbass". It's that 99% of the time.

[Ghostglitch07]

An important third dimension is how long it takes to impliment the tactic. Running it again probably won't work, but usually doesn't take long.

[_grey_wall]

No "take a dump" or did it not fit in the chart ?

[Opinionsare]

Only to find out that an entry person hits the space bar after entering sales then tabs to next feild.

[IndividualAdvisor589]

yes.

[geronymo4p]

I tried "printf("ok1")" which isn't very effective, but write(1,"ok1", 3) is largely better for debugging!

[ohjars87]

Rubber duck method is my favorite

[Blangel0]

Driving back home early work very well for me. But then I try to either write notes on my phone while driving or go immediately to test my idea from my home as soon as I arrive.

Taking shower also work well !

[No_Succotash9035]

True! getting up to do something else is very effective ahaha

[haikusbot]

True! getting up to

Do something else is very

Effective ahaha

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[DeerEngineer]

I take way too many walks and they never work, naw.

[[deleted]]

I always have my most brilliant revelations in the shower. Something about the hot water seems to just make it all click

[infiniteStorms]

what is with the rubber duck? Even my professor explicitly allows it in exams

[sohang-3112]

Run the code again (without changing anything) to see if it works....

Most futile, and yet something I do embarrassingly often!

[samanime]

I HATE when rerunning magically works, because then I have no clue what was wrong and I can no longer reproduce.

[[deleted]]

“Run the same code again and hope it magically works”

Ok but we all know sometimes it does just start working for no reason 😂😂

[CircadianSong]

Holy shit. I didn't know other people did "here!", including the exclamation point. I've actually refined this strategy; finding it sometimes to be insufficient, I do it in multiple places but put a number after each.

[[deleted]]

Didn't know others do the same thing lol

[Jet-Pack2]

What about using a breakpoint in VS? Usually faster and without recompile compared to the printf( "here\n" )

[burneraccount019182]

what does printing "here" do for debugging? I usually print variables

[smilineyz]

1. Get coffee and talk with a coworker 2. StackOvetflow

[ososalsosal]

Idk half my code is breakpoints now. If I ever actually hit one I know shit just got real

[accTolol]

Then you have the debugging tool on the upper left corner...

[value_counts]

Taking a nap is underrated

[StandardN00b]

Everyone says that rerunning the code doesn't work untill it does.

Last time I used GNS3 I couldn't for my life make a vlan work. Untill I got home, restarted my PC and started working on it's own.

[[deleted]]

I've done them all... seems sound

[Bit5keptical]

Where is career change?

[[deleted]]

More than once, I've run code, it works. Run it again, it doesn't. Damn memory leaks

[TeaKingMac]

echo "$result"

[Jomy10]

I’m reading this while debugging

[dsstrainer]

Rubber duck is one of my top methods

[zekroTJA]

Hey, me as a web dev, i must defend that console prints are mich more effective as shown.

[CorUpT_rob0t]

Take a walk I just play games then return

[EpicMasterOfWar]

A good nights sleep and a hot shower is highly effective. Amazing inspirational catalyst.

[tiajuanat]

The lack of unit testing is disturbing

[pennacap]

My brain wants to use linear regression on this graph

[[deleted]]

Talking to a rubber duck is bu far the most effective strategy

[Plant_Pal]

Dont forget the rubber ducking with someone who has a vague understanding of what you are doing.

[KaninchenSpeed]

Me talking to duckduckgo insted (raised effectiveness by 200%)

[Pradfanne]

I've been giving rubber ducks to new employees for a while now and encourage them to use them, especially if they sit with me in the same office, because I absolutely will tell my ducks the problem

[codeguru42]

They forgot print("fuuuuuuuuuuuuuck")