But all of the engineers passed LeetCode, how could this be?
If you want to criticize something, criticize the testing that let this change through, not the developer who made it. We were all young and inexperienced once, we've all had bad days, and we've all written crap code. This is only unique because it affected a lot of people.
The large amount of people affected reinforces your parent comment's argument. Something that has the potential to affect an immense amount of people should be treated with a relative amount of care. Writing crap code and pushing carelessly would be a far more significant failure of judgement if that code were in the Facebook SDK than if it were in Johnny's Hello World App.
It's also worth noting the difference between writing code with a minor change in behavior that when pushed to production causes an unexpected domino-effect of obfuscated cascading failures across multiple different services that eventually impacts an immense amount of people, vs. directly writing code that crashes on the client side and impacts an immense amount of people. This is the latter.
Criticise the process that let it through.
Why was the testing not sufficient? Was it even tested at all? Maybe a developer just "pushed it straight to master"? Why/how can they do that (hypothetically)
It's not that they aren't smart or don't learn but that FB's performance review process rewards optimizing for growth over reliability/sustainability.
e: you can downvote me but I lived it so you won't change my mind :)
Which begs the question why test engineers with leetcode trivia bullshit. You are yourself emphasizing why their interview process (and they are just one of many offenders) is so bananas inappropriate.
https://www.darkcoding.net/software/facebooks-code-quality-p...
https://blog.timac.org/2017/0410-analysis-of-the-facebook-ap...
Granted, perhaps things have gotten better in the last five years.
It's certainly possible for an enormous engineering company to have poor code quality or poor engineering practices, despite having a high interviewing standard. And a criticism of Facebook need not be a criticism of all companies that interview by Leetcode, for instance no one here is criticizing Google, Amazon, or Apple, and all have better reputations for code quality.
[0] https://www.reddit.com/r/iOSProgramming/comments/6upeu6/how_...
[1] https://www.facebook.com/notes/facebook-engineering/under-th...
You’re describing the attitude Facebook takes towards candidates, not the attitude I take towards anything.
Candidates should be saying to Facebook, “ I really hope all of your code is perfect every single time to be acting so high and mighty” and absolutely making a huge deal out of a case like this when it isn’t.