turing complete with a stack of 0xdeadbeef
I previously wrote about implementing Dark Mode in an older codebase, specifically how Dark Mode works (or doesn’t) with CGColor. I recently fixed a bug in the same project that was difficult to track down because it manifested in such a strange way. After finding the problematic code, I realized that it is an extremely common scenario in iOS codebases — so you might have this bug in your code as well!
I was recently working on a project that uses modern collection views on iOS — that is, using diffable data sources, snapshots, and cell providers. I hooked up all the components and my collection view was working, or so I thought. I started to notice some very odd, unpredictable behavior when the collection view was updated. Some of the time, the cells were updated correctly. Other times, I would see duplicates and missing data. Here’s what went wrong.
Previously, I wrote about Time Machine “error 45”, an obscure bug in macOS Catalina. I still have no idea what was causing backups to fail, nor what “error 45” means. However, I am happy to report that I think this issue has been fixed in Big Sur.
This post is mostly for posterity, for anyone currently experiencing these bugs on macOS, and to praise Titanium Software’s excellent Mac utility app OnyX.
The Touch Bar on my MacBook started freezing and experiencing UI glitches recently. It was completely unresponsive. At the time, the only way I knew to fix it was to reboot my entire machine, which felt ridiculous. Luckily, there is a better way.
This is a first for me. I returned to my MacBook after leaving it for a couple of hours, and it was shutdown even though I left it powered on. The machine was idle. I didn’t have any specific tasks running. I figured it might have been a macOS kernel panic, but upon rebooting I discovered that the crash was caused by bridgeOS.
This is a brief follow-up to the post I wrote about Time Machine failing on macOS Catalina.
When I first upgraded to macOS Catalina, there was a “Relocated Items” folder on the desktop. Well, actually it was an alias to /Users/Shared/Relocated Items/. This was expected, given the new “security features” in Catalina, which includes a new read-only system volume. What I did not expect was to see this folder reappear with every single update.
Core Data is probably loved as much as it is shunned by iOS developers. It is a framework of great power that often comes with great frustration. But it remains a popular tool among developers despite its pitfalls — likely because Apple continues to invest in it and encourages its adoption, as well as the availability of the many open-source libraries that make Core Data easier to use. Consider unit testing, and Core Data gets a bit more cumbersome. Luckily, there are established techniques to facilitate testing your models. Add Swift to this equation, and the learning curve gets slightly steeper.