[tgma]

Craig Federighi on some podcast once said they conducted dry-runs of the process in previous iOS updates (presumably building the new APFS filesystem metadata in a file without promoting it to the superblock) and checking its integrity and submitting telemetry data to ensure success.

[3eb7988a1663]

You can do all the testing in the world, but clicking deploy on that update must have been nerve wracking.

[Gigachad]

Apple doesn’t just deploy to the whole world in an instant though.

First it goes to the private beta users, then the public beta users, and then it slowly rolls out globally. Presumably they could slow down the roll out even more for a risky change to monitor it.

[tgma]

Sure, but still whoever wrote the patch had his ass on the line even shipping to a batch of beta users. Remember this is Apple not Google where the dude likely got promoted and left the team right after pressing click :)

[SequoiaHope]

Very much worth saying that many of the people what write code at Apple are women. Some of them are my friends.