What’s the most frustrating bug you’ve ever squashed, and how long did it take?

Like 6 months of it appearing and disappearing. It was a pointer issue in code someone "wrote in a weekend".

For me it was certain time bookings not going through into our CRM and also no logs appearing regarding them.

Yeah, turns out it was my fault.
I suppressed the logger during the "section" in which they are processed.

And since logger suppressings are applied pre building, I didn't find anything for like half a month...

...until I went through the generated JS code by hand and eventually found it.

Fuck me...

I was working on an interpreter and got stuck, very stuck. I don't accept that and move after a hour to next project. So, that happened many times before figuring out that the " token consumed also the char behind it. So aaa="bbb" was OK. {"aa":"bb"} didn't parse. It can't be an issue with the tokonization that's working perfect for weeks right? Hmm, the : is new, it must be that one. Hmm, it doesn't parse it.. Oh fuck, does it get parsed completely in a different branch? It is consumed. Had to be. Sigh, what a hell. With aa="bb" went well because the \n just got consumed. The tests only checked if it just parsed. Not if it was bb instead of b.

Other one was like:
Pony * pony = (Pony *)malloc(sizeof(pony)). See what I did there? It caused issue at random place in code completely unrelated. I found it fast by extreme luck.

Have you ever tried to make a complex synchronous library including complex UX interaction work with React? It does not play well. Took me a month to find the bug, 3 minutes to fix it.

@retoor
I’m sure you sweated when you wrote your bug in that thread.

QA reported that something doesn‘t work and no matter what I did, I couldn‘t reproduce it.
It always worked on my side.
It took me weeks of releasing blind guess fixes to the test system and none of them worked.
Then I decided to refactor a big chunk of the app where this problem seems to appear and that finally fixed it.

It‘s always the ones that are not reproducible or occur sporadically.
Those make you question your sanity.