Especially painful being a cybersecurity engineer;

Did something wrong with an if-statement.

Caused authentication to break completely; anyone could login as any user.

Was fixed veeeeeeery quickly 😅 (yes, was already live)

Trying to exit a bash script with 'halt'

on a friday afternoon

ran w/ root

on a internal prod-vm

which I did not had the permissions to turn on again

Three months into a new job, as a senior developer (12+ years experience) and updated an import application.

With one small update query that didn't account for a possible NULL value for a parameter, so it updated all 65 million records instead of the 15 that belonged to that user.

Took 3 people and 4 days to put all the data back to it's original state.

Went right back to using the old version of the apllication, still running 2 years later. It's spaghetti code from hell with sql jobs and multiple stored procedures creating dynamic SQL, but I'm never touching it again.

When working with hardware some mistakes can be literally painful. Thankfully this was all during undergrad and I'm only around computer hardware now lol.

>Misprogrammed a software kill switch so a sensor that should not have been sending data was actually sending data which caused the system to activate a piston that went WHAM! into the face of a teammate working on replacing some part of it...

>Misprogrammed a controller so it drew too much power from the supply and the puny supply wires literally burst into flame and fell across my arm.

>Spun a 9000rpm CNC spindle the wrong way and caused an attached screw to go rocketing upwards instead of downwards and almost break the (pretty expensive) thing (uh...we were trying to use it as a power screwdriver essentially but I set the rpm to about 100x what I wanted and the direction wrong so yeah).

>Switched a -1 with a +1 in a robot's control system sending it careening into a teammate's leg... let's just say mecanum wheels are paaaainful.

I once added a semicolon at the end of a line when coding in Python.

I’ve brought shame on my family.

My most painful coding error?

```
#!/bin/bash
APP_PREFIX=${1}

#Clean built bin dir before re-compiling
rm -rf ${APP_PREFIX}/bin

make compile
```

One time, I was working with an org that got a new senior executive from Microsoft. He decided we needed to throw out our application's java stack and replace it with SharePoint. The code error was committing anything other than my immediate resignation.

Took me 6+ full days.

The feature does not work. Repro is unknown, so only prod is experiencing the issue.. Which rules out the debugger option. Sometimes there's an entry seen in logs: "java.lang.StringIndexOutOfBoundsException". Nothing more - just that. No stack, no class, no nothing. Is it my code that's buggy? Is it some config? Integration? Unexpected response...? A bug in a lib? Is dimm faulty ir maybe server's shared libs are off?

Turns out I used a closing parentheses instead a closing curly bracket in an error message that's supposed to be interpolated...

String message = "{some-business-rule-related-error-message-key)";

took me 6+ full days... But I found it. Took the rest of that Friday off to walk in a park and enjoy my life :)

While coding in C, I once forgot to add a semicolon at the end of a while loop polling a register value.
The logic required me to make it zero as soon as it read non-zero and continue the rest of the process. Hence the 'while' that missed the semicolon ended up being a single instruction assignment to the same volatile register that I kept polling. This caused synchronisation issue with the FPGA, and my code got stuck in an uncertain infinite loop.
Took me 2 days and a silly, yet valid question from my teammate to figure out the cause of this stupid bug.

Most painful code error you've made?

More than I probably care to count.

One in particular where I was asked to integrate our code and converted the wrong value..ex

The correct code was supposed to be ...

var serviceBusMessage = new Message() {ID = dto.InvoiceId ...}

but I wrote ..

var serviceBusMessage = new Message() {ID = dto.OrderId ...}

At the time of the message bus event, the dto.OrderId is zero (it's set after a successful credit card transaction in another process)

Because of a 'true up' job that occurs at EOD, the issue went unnoticed for weeks. One day the credit card system went down and thousands of invoices needed to be re-processed, but seemed to be 'stuck', and 'John' was tasked to investigate, found the issue, and traced back to the code changes.

John: "There is a bug in the event bus, looks like you used the wrong key and all the keys are zero."
Me: "Oh crap, I made that change weeks ago. No one noticed?"
John: "Nah, its not a big deal. The true-up job cleans up anything we missed and in the rare event the credit card system goes down, like now. No worries, I can fix the data and the code."
<about an hour later I'm called into a meeting>
Mgr1: "We're following up on the credit card outage earlier. You made the code changes that prevented the cards from reprocessing?"
Me: "Yes, it was my screw up."
Mgr1: "Why wasn't there a code review? It should have caught this mistake."
Mgr2: "All code that is deployed is reviewed. 'Tom' performed the review."
Mgr1: "Tom, why didn't you catch that mistake."
Tom: "I don't know, that code is over 5 years old written by someone else. I assumed it was correct."
Mgr1: "Aren't there unit tests? Integration tests?"
Tom: "Oh yea, and passed them all. In the scenario, the original developers probably never thought the wrong ID would be passed."
Mgr1: "What are you going to do so this never happens again?"
Tom: "Its an easy addition to the tests. Should only take 5 minutes."
Mgr1: "No, what are *you* going to do so this never happens again?"
Me: "It was my mistake, I need to do a better job in paying attention. I knew what value was supposed to passed, but I screwed up."
Mgr2: "No harm no foul. We didn't lose any money and no customer was negativity affected. Credit card system may go down once, or twice a year? Nothing to lose sleep over. Thanks guys."

A week later Mgr1 fires Tom.

I feel/felt like a total d-bag.

Talking to 'John' later about it, turns out Tom's attention to detail and 'passion' was lacking in other areas. Understandable since he has 2 kids + one with special-needs, and in the middle of a divorce, taking most/all of his vacation+sick time (which 'Mgr1' dislikes people taking more than a few days off, that's another story) and 'Mgr1' didn't like Tom's lack of work ethic (felt he needed to leave his problems at home). The outage and the 'lack of due diligence' was the last straw.

An hour of "WHY ISN'T ANYTHING WORKING" followed by ashamedly squashing 20+ local commits and actually remembering to git push the result that time.

I once made an oopsie in an API for a logistics provider (one of the biggest in Germany...).

To understand the oopsie...

Based on input data a string must be created containing several hex / string / formatted values.

Think of ...

$return .= sprintf("%02X", ...)

I think there were around 15 to 20 lines, although more complicated.

The bug happened because I had a brainfart.

What was previously one line with... Many many many many variables, I had to split into multiple lines since internal stuff changed and it was impossible to change this oneliner of hell with >50 formatting codes.

Of course we didn't test everything.
XD

What we didn't test was - funnily enough - wether the casting was correct in all cases.

I misplaced a formatting code.

And we had a major brainfart because we tested integer, but not double / float values....

We sent for a long time packages much cheaper than allowed (took thw logistics provider nearly 3-4 months to realize this :) ).

Spot the difference:

@highlight
print sprintf("%01.2s", $money).PHP_EOL;

print sprintf("%01.2f", $money).PHP_EOL;

i was helping a friend with their coding assignment - snake game.

we spent about 45 minutes of trying to figure out why the snake's self-collisions are not working.

then we realized that she's using two separate arrays/grids - one for the food, one for the snake itself.

she was checking both for food collisions and self-collisions on the food array.

it was very painful to realize it took me so embarassingly long to notice it.

Two words that instill fear in any database developer: Cartesian Join.

I didn’t realize what was happening until the DBA paid me a personal visit asking what I was running that had cached over a billion rows.

I don't have a "most painful error".

The real pain for me is the

WHY ISN'T THIS WORKING

I'VE DONE THIS 1000 TIMES BEFORE

THIS ISN'T HARD

THIS SHOULDN'T TAKE THIS LONG...

It's just the worst combo of events / feelings / leads to the hopeless depths of imposter syndrome and etc.

The feature was to parse a set of fairly complex xml files following a legacy schema. Problem was, the way this was done previously did not conform to the schema so it was a guideline at best, which over the course of many years snowballed into an anarchy where clients would send in whatever and it was continuously updated per case as needed. They wanted to start enforcing their new schema while phasing out the old method.

The good news is that parsing and serialization is very testable, so I rounded up what I could find of example files and got to work. Around the same time I asked our client if they had any more examples of typical cases we need to deal with, and sure enough a couple of days later I receive a zip with hundreds of files. They also point out that I should just disregard the entire old set since they decided to outright cut support for it after all if it makes things simpler. Nice.

I finish the feature in a decent amount of time. All my local tests pass, and the CD tests pass when I push my branches. Once we push to our QA env though and the integration tests run, we get a pass rate of less than 10%.

I spend a couple of days trying to figure out what's going on, and eventually narrow it down to some wires being crossed with the new vs. old xml formats. I'm at a loss. I keep trying to chip away at it until I'm left with a minimal example, and I have one of those lean-back moments where you're just "I don't get it". My tests pass locally, but in the QA environment they fail on the same files.

We're now 3 people around my workstation including the system architect, and I'm demonstrating to the others how baffling and black magic this is. I postulate that maybe something is cached in my local environment and it's not actually testing the new files. I even deleted the old ones.

"Are you sure you deleted the right files?"

"Duh of course -- but let me check..."

This literally happened in my current team, and I'm not even an experienced dev yet.
Incident happened like this :
Our team is working on a RCP based on eclipse plugins, which has a headless mode and a GUI mode. Now, in the GUI mode, my manager cum architect thought there are no need of user log files (long story) because the user can see the info on screen, whereas in the headless mode, she wanted me to print the logs onto the console and a log file as well.
Now it just so happened that our team had got a recent addition as a replacement to our lead developer (she left the company) who claimed she had 3 years of expertise and a masters degree, and she was assigned a task. The task was to format a custom file we were generating out of the product (basically dumping info in a file) in a human-readable format. Miss new-addition-masters-degree decided it would be a very good idea to redirect the standard java output stream to a file output stream ( which she used for generating the formatted file ) but somehow never realized that she needed to reset the output stream back to standard output.
Consequences were devastating. I wrote the logic for the logger ( yes, apparently any available logging mechanism won't do it, again, long story ) and had it printing to a file in tmp directory. The logs seemed to be working fine initially but after a few logs, specifically from the point where the formatter started working, all the logs got printed in the formatted file. And this file was supposed to be used by our clients to develop something on top of it. Naturally, I got the heat of it and then naturally, worried and nervous and curious and in a frenzied state of mind, I started debugging.
When I got to the actual fault, I seriously could not decide whether to cry or laugh or call up miss masters and scream at her. I decided to ask her about what the hell she had written and her answer was most of it was written by the developer she replaced, so she didn't know it would cause this much problem. Anyway, I fixed the leak after that and averted the catastrophe.
And that, fellow devs, is the story of how I solved a crisis in my first year at corporate.

Lost 2 days with a non-highlighted error.
Vanilla JS:
Calling a function with a lower case character which shouldn't be lowercase.
I didn't never understood why neither VSCode nor Chrome showed the error.

I was new to C++. Spent a few days debugging a crash caused by an uninitialised variable.

When you have two projects opened and you changing code in one project but running another
And going crazy as you do not see the changes...
Happened 2 times with me 😂😂😂

I fixed a bug properly... Took down an entire application systems, sometimes you just gotta monkey patch that shit.

So it was a 15 year old cold fusion system and chrome had deprecated some window pop up feature, so I tracked it to the shared function that triggered this, fixed it there, tested it and even got it all past qa.

Turned out some of the other modules on the app had some other logic around this that made it not work there, they had implemented the fallback check without any fallback logic.

Time to rollback a 3 week sprint...

Pfft easy: Segmentation Fault.

I ran a big long-running terraform apply and somehow thought it would still work if I locked my laptop.
When I went back the next day (I know lol) terraform was hanging, had to force stop which screwed up the remote tfstate.
Had to spend a whole day manually deleting about 70 AWS resources that terraform created but had no knowledge of because of the corrupted state.

I once had to write an http interceptor for a distributed api. The interceptor needed to use the request context and the user profile to work out if a particular type of content had previously been accessed. Anyway there were two methods to get the user profile getUserC and getUserD, turns out C stood for cache D stood for database. Of course I called getUserD I effectively wrote a database distributed denial of service tool into our app 😬 we got a call from our customer complaining that their exadata servers where grinding to a complete halt

Maybe not the worst but the worst one I can remember for sure and it happened recently. I may or may not have spent 4 hours with another developer working out why my script didn't work.. to realise that I had swapped the underscore in a method name for a period. No wonder everything came back undefined when I was dotting into a method that didn't exist 🤦🏻‍♀️ my only highlight was that the more experienced dev was there with me and he also couldn't find it for all that time lmao. I did briefly contemplate calling my University and asking them to just take my diploma back, I don't deserve it lmfao

Must've been when I coded something of the core module of a game... into and with the test interface.
I was reminded that by my colleague who initially made this and spent a huge ton of time more than anyone else on the project. I felt a bit powerless while trying to assist in that, but I also felt bad about that error of mine.

...

That or that time when I set my whole system to protected and read-only during a system programming exercise because it ran out of memory real fast.

Null Pointer Check 😟

Any code i write in Android studio.
That piece of shit would just go take a nap in the middle of my coding . I can no longer get response from mouse or buttons
Its bloody painful. I love it

Back in college I was writing a parser for a personal project in python. I was adding nodes to a set, but somewhere down the pipeline, some of the items I added to this set mysteriously disappeared!

I never removed anything from this set, nor did I replace it, so it baffled me that I couldn't find some items in the set.

It turned out the problem was I updated fields in these nodes that were used for taking the node's __hash__, which would prevent them from being found in the set

:|

Not really most painful, but definitely most painful of the recent bunch..
// yup, a bunch.. I've managed to fuck up a little on every thing I did that day :/ little friday the 13th for me, especially as I went on sick leave the next day and had to fixup my fuckups with a friggin migrane..

Anyways, I was fixing fallback to some default value in plsql.. before it didn't check what the input format was and simply relied on certain format, parsed that and converted to number..threw an error, duh!

I fixed it somehow elegantly to check with regex if the format is as expected and if not default to xy value..and if format is as expected to parse out the number..except that when I copied (or typed?! for the sake of me, I cannot recall how the fuck I managed to fuck this up) over the code to the package I didn't see additional [ at the begining, so everything went to the default.. Most embarrassing part is I commented everything, how it should work, use cases, what the input was and what was expected output..and failed to see the friggin extra [..
It was fixed easily, the extra [ stood out later when I saw the code, but it bothers me how I managed to overlook that in the first place. I think I need a vacation.. but have to fix other fuckups first.. :/

Null reference exception wins everytime!!

I was new to Android development back then. One of the project requirements was to implement a feature, that will prevent the users from turning off the phone. Even if the users tries to turn off, the phone shouldn't turn off (specially when the phone battery is sealed). So, I tried a method and it works! But later the users reported that the feature doesn't work! I mean, I can clearly see that the feature works in all the phones I have ever tested. But later I realized that the feature worked in Debug APK but not in Release APK. I mean, seriously? It's not even some kind of pro-guard issues that happens with GSON+Parcelable. So, I did it again using a new method. Again, it works in Debug but not in Release. After trying and failing multiple times, finally I found a solution! May be this bug alone took me almost a week to fix it!

Most painful code!!
Well , it was to write a code in 'C' which will print first N times prime numbers. As a noob , it was really very painful.