turing complete with a stack of 0xdeadbeef

Writing

I mostly write about Swift, Objective-C, iOS, open source, and other software development topics. Sometimes I write about the ethics of tech, labor, and politics. I also write personal essays and notes on what I'm currently reading.

Useful label-based GitHub Actions workflows

24 August 2021

My current team has started using GitHub Actions to automate some tedious tasks for pull requests. In particular, we use labels on GitHub to categorize pull requests or highlight important metadata about them. Most of the time, a machine can figure out which labels are appropriate to add or remove. This is a great use case for GitHub Actions.

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Different ways to observe properties in Swift

08 August 2021

After I wrote and released Foil, my library for implementing a property wrapper for UserDefaults, one of the criticisms on Twitter was that a mechanism for observing such properties should have been included. I disagreed. In the post I argued that this was easy enough for clients to handle on their own, but more importantly that there are too many options for how to do this and I didn’t think Foil should impose any one of them on clients.

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Fixing a hard-to-find bug in Dark Mode

15 July 2021

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!

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Debugging a DiffableDataSource CellProvider

11 July 2021

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.

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Is SwiftUI ready?

01 July 2021
Updated: 11 September 2021

I’ve been following what’s going on with SwiftUI since it was released with iOS 13 at WWDC 2019 and have even taken extensive notes, but I have avoided using it. As I wrote before, I mainly wanted to avoid dealing with bugs and workarounds that might make me less productive compared to using UIKit, which I know quite well. I’m very interested in learning and using it, I’m just hesitant given some of Apple’s history, like early years of Swift. I have no doubt that SwiftUI will be the future of Apple platform development, the question is when that future will arrive. This year the framework is debuting its third major release in iOS 15. How far has SwiftUI come, and is it ready for building serious apps?

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RSS feeds, Jekyll, and absolute versus relative URLs

06 June 2021
Updated: 09 June 2021

Lately I’ve been upgrading and making improvements to my website and blog. As part of that work, I was updating and refining how my RSS feed gets generated with Jekyll. And then I realized something that I had not given much thought to previously. When including the full content of blog posts in an RSS feed, if you link to other posts or pages on your site should you be using absolute URLs or are relative URLs ok?

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To distribute in the Mac App Store, or not

Is the app sandbox worth it? 02 June 2021

For the past few weeks I have been debating on whether or not to distribute a new Mac app via the Mac App Store or independently. I have arrived at a crossroads in development where I need to make this decision. I am mostly code-complete for my MVP 1.0 release. The question I am facing is how I want to spend the remainder of my time to cross the finish line.

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Three months of Big Sur

01 June 2021
Updated: 09 June 2021

I upgraded to Big Sur three months ago. I know I’m (fashionably?) late to this party, but here I am. This is the longest I have ever waited to upgrade macOS. It feels weird, considering WWDC is next week where we will see what is next for macOS. Big Sur still feels new to me, and announcing the next major release already feels too soon. I was avoiding Big Sur based on various reports about bugs and instability. There were not any ‘killer’ features I was eager to have, thus the main reason I upgraded was because Xcode 12.5 required it.

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Resources for learning SwiftUI

07 April 2021

A few months ago, I shared my notes and resources for learning about compilers and LLVM. It turned out to be pretty popular and folks seemed to find it useful. So I decided to do it again, but this time for SwiftUI. However, unlike learning about compilers and LLVM, I am not declaring bankruptcy with learning SwiftUI. While I have still not written a single line of SwiftUI code, I know I eventually will.

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Migrating OmniFocus to a new Mac

31 March 2021

One aspect of using OmniFocus involves maintaining an archive of your data (if you choose). Over time — think years of using OmniFocus as your main task management tool — your local database of projects and tasks will grow very large, because OmniFocus keeps a record of everything you have completed or dropped. You can think of it as archiving your emails instead of putting them in the trash.

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Xcode tips for everyone

22 March 2021

Lately, it feels like every few days someone is sharing a new Xcode tip on Twitter or on their blog. They range from hidden settings to features I simply never knew about. I started saving links and planned to add a new “Xcode tips” section to my TIL repo on GitHub to reference later. But as I started, I realized that the resulting markdown file would not be easily discoverable or shareable. I thought, wouldn’t it be nice if the iOS and macOS developer community had a single place to find and share Xcode tips?

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Using pipes in Swift scripts

18 March 2021
Updated: 22 March 2021

I have a few Swift scripts to automate tedious tasks for maintaining my blog. I updated one today to use pipes. It took me a minute to figure out, because it did not feel very intuitive. I’m not sure if I feel that way because the interface is actually that clunky, or if I’m just inexperienced with Swift scripting. In any case, here’s how it works.

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Xcode UI testing reliability tips for iOS

17 March 2021
Updated: 18 March 2021

Xcode’s UI testing framework has had its ups and downs over the years. Most recently, it has been much more robust and reliable in my experience. However, tests still tend to flake sometimes. Here are some ways that I have been able to reduce flakiness in UI tests.

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Resources for learning about compilers and LLVM

28 December 2020

Today I cleaned up my various projects and todo’s in OmniFocus. I am always collecting links and resources for potential project ideas, or for general learning. Sometimes, however, it is best to acknowledge that I will likely never have enough free time to even begin some of these endeavors.

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What type is self in a Swift self-executing anonymous closure used to initialize a stored property?

The answer might surprise you 22 December 2020

In JavaScript, this pattern is called an Immediately Invoked Function Expression (IIFE) or a Self-Executing Anonymous Function. Swift doesn’t have an “official” name for this, but IIFE works as well as “immediately executed anonymous closure” or “self-executing anonymous closure”. (Thanks to folks on Twitter for helping with this.)

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Obscure bridgeOS crash

22 December 2020

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.

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Useful Danger rules for Bitrise

20 December 2020

This is a quick follow-up to my previous post. The client project I’m working on is also using Bitrise for CI, which I must say is quite good. If you are looking for a hosted CI service I would highly recommend checking them out.

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Running multiple instances of Danger

15 December 2020

For a client project that I’ve been working on, I recently integrated Danger to automate pull requests for the team. I initially setup a single Dangerfile to run on CI, but soon after we had the need to split it up in order to run danger more than once for a single CI run.

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