The adoption of strict concurrency in Swift is not an easy process in some projects. Implicit assumptions we usually make are often challenged by the compiler, and we don’t know how to solve them in many cases - leading to frustration among us, developers. The amount of keywords also doesn’t help: tasks, sendability, isolation domains and boundaries, actors, preconcurrency, and the list goes on.

If you’ve been active on Mastodon, in the iOS development world, there’s a person that is frequently mentioned in questions or errors about Swift’s strict concurrency: Matt Massicotte. While working on his open-source projects, he recognized the opportunity to migrate them and deepen his understanding of structured concurrency.

In this 4th episode of Dev Conversations, he joins us to talk about his experience with Apple platforms even before the introduction of OS X; a bit about his work on improving the iPhone’s battery life in the late 2000s, and also the early days at Crashlytics.

But the main focus of the conversation is Swift 6’s strict concurrency. We discuss the factors one should consider before adopting it, the feelings we face when encountering enigmatic errors, and also suggest practical solutions and strategies to upgrade to strict checking with peace of mind.

• Website
• GitHub
• Mastodon

• ConcurrencyRecipes
• Queue
• MainOffender
• Chime

• Swift.org: Migrating to Swift 6
• Talk @ Swift TO: The Bleeding Edge of Swift Concurrency
• Should You Enable Swift’s Complete Concurrency Checking?
• Problematic Swift Concurrency Patterns
• Making Mistakes with Swift Concurrency
• Crossing the Boundary

• Swift 6 + Concurrency = Peace: Talk by Muralidharan Kathiresan at SwiftConnection 2024

Adam Fowler and Joannis Orlandos are both active members of the Swift Server Workgroup. Adam is known for his contributions to Soto (a community supported Swift SDK for AWS), and to the VS Code Extension for Swift, amongst other packages. Joannis was a contributor and core team member at Vapor, and is involved in many Server Side Swift projects: he created MongoKitten (a MongoDB Driver for Swift), and is a maintainer in RediStack and CoreOffice.

In the last few months, they have been working together on a new major version of a lean and modular web framework in Swift: Hummingbird 2.

In this Dev Conversations episode, Adam and Joannis join a chat where we talk about the evolution of Soto, working with Swift in VS Code and how Dev Containers are helpful, and how not, Hummingbird 2. As Joannis told his jounery in the Swift on Server world, we discussed the key differences between Hummingbird and Vapor, lessons learned along the process, and how the two frameworks help each other and the Swift community as a whole.

• Website
• GitHub
• Mastodon
• Soto (Website)
• Soto (GitHub)
• VS Code Swift Extension

• GitHub
• Swift On Server
• X
• Mastodon
• ServerSide.swift 2024: Introduction to Hummingbird 2
• ServerSide.swift 2019: API Performance A Macro Talk About Micro Decisions

• Website
• Discord
• GitHub
• Examples Repo

Dave Verwer is well known in the iOS developer community, mostly for his iOSDevWeekly.com newsletter, which he’s been publishing for more than a decade. In the recent years, Dave and Sven A. Schmidt have been working on the Swift Package Index - a website that does much more than just listing Swift packages. It shows, for each listed package, a matrix of supported platforms, Swift versions, and also allows launching a playground with a package to try it out!

After listening to some of their podcast episodes, and peeking at the organization repositories on GitHub, I was sure it could yield a great talk about the different pieces they have built when creating the website. The Vapor server, the tools to digest packages, documentation hosting for package, the infrastructure that supports it all…

Sven and Dave both kindly accepted my invite to join another Dev Conversations episode. We chatted about its history, all the pieces behind the scenes, the state of Swift 6’s strict concurrency. Wrapping up, we also discussed how demanding this project became, and how essential is the community support, from GitHub Sponsors to the companies that contribute to it (MacStadium, Microsoft, and since 2023, Apple).

• Website and Blog
• Discord
• GitHub
• Podcast
• Ready for Swift 6
• Post: Switching to ephemeral macOS build runners
• Mastodon
• Percy by BrowserStack

• Website
• GitHub
• iOSDevWeekly.com
• Talk: How I Accidentally Ended Up Running The Largest Open-Source Vapor Website

• Website
• GitHub
• Mastodon

The first time I spoke with Andrew was in the first half of 2024, while I was checking out his Swift runtime for Vercel Functions. What I didn’t know then, was the fact he is the developer behind Swift Cloud. It initially launched as a hosted platform, but Andrew just announced and released a new vision for Swift Cloud: an open source framework to deploy Swift server applications, that is agnostic to the cloud provider and the application type (Vapor, Hummingbird, Lambda). The great thing about it is the infrastructure code abstracts lower level concepts and technologies (such as Dockerfiles), enabling the developer to describe in Swift the server infrastructure.

I messaged Andrew around a month ago, before his Swift Cloud announcement, asking to interview him for this series. Not only he right away agreed, but he was kind enough to help reviewing the hands on article covering Swift Cloud, and constantly listening feedback about its API.

Today he joins us for the first recorded episode Dev Conversations. Here we talk about his career, from an intern on the early days of WhatsApp in 2012, until his current position at Vercel and his work and future vision for Swift Cloud.