No, clearly not. Take a look major components rewritten in recent years, such as Xcode code editor, new build system, Dock, those are crashing way more than their ObjC/C counterparts for whatever reason. A crash is a crash. You may claim that errors here are “less fundamental”, but the fact remains that the new software crashes more than the old.

Right. Users don't give a hoot what language the software is written in, what design patterns you're using, if you're functionally immutable. The code is there to serve a purpose. If it crashes, it fails; the root cause doesn't really matter to the user.

This feeling that “man dock.app is crashing more” followed by a few otool queries showing more Swift libraries gives me a vague suspicion that Swift rewrites have been leading to more end user noticeable crashes. I’d find it interesting to see some actual statistics on it in the form of “x crashes per 1 hour of program usage”. Perhaps it’d actually be lower than Obj-C but it doesn’t feel that way. Is it due to Swift error handling or just to rewrites? This would be an ideal time to get such statistics ! As it’s not often a giant platform starts switching to a new language and offer the chance to gather real stats rather than bikesheading or doing undergrad cohort experiments would be very interesting.

Sure, if it's a good old whole-program-crash either way, that means they're equivalent severity. It's not my intention to softball Swift with some nebulous idea of what counts as a proper 'fundamental' bug.

In defence of Swift, it could still be that they spent less time bug-hunting than when they were developing in Objective-C, to reach the same, or inferior, level of program correctness.

Also, we're comparing a new product to a mature one. Were the original Objective-C programs stable in their first release?

My point isn’t to say Swift is bad. I personally don’t like it, but that isn’t the point. In my original comment, I wanted to say that rewriting software just because of a new language is probably a bad idea.

Apple could have continued using the existing software, rather than just throw away stable code for the sake of new devs to use a new language.

Agree completely - I'm not convinced that Swift is so much better than Objective-C that it makes sense to throw out mature production code.

Mandatory link to Spolsky's blog post on exactly this:

https://www.joelonsoftware.com/2000/04/06/things-you-should-...