LOADING

Migration Without Tears: 2,000 Projects, One New LTS

In this talk, I will present insights from running the Open Community Build, where we continuously build and migrate nearly 2,000 open-source projects to the newest Scala Next versions, from scratch, every week.

Wojciech Mazur
Scala Compiler/Tooling Engineer @ VirtusLab
About This Talk

Scala 3.3 introduced the first Long-Term Support (LTS) release, setting expectations of stability, incremental improvements, and a predictable migration model - while innovation continued through the Scala Next release line.

Now, three years later, Scala 3.9 becomes the new LTS baseline, marking the next major migration point. But this cycle is fundamentally different: the compiler and tooling can now automate a large portion of migration effort, allowing teams to focus on product development rather than manual refactoring.

In this talk, I will present insights from running the Open Community Build, where we continuously build and migrate nearly 2,000 open-source projects to the newest Scala Next versions, from scratch, every week. This effort surfaces real-world compatibility issues long before they reach users, providing a unique perspective on how migrations behave at scale.

You’ll learn:

- How to approach migration to 3.9 LTS using compiler automation

- The most common problems observed when upgrading

- What breaks in practice, and how to fix it efficiently

- How Community Build feedback loops accelerate ecosystem stability

- Strategies for migrating libraries, applications, and whole ecosystems

This talk is not a feature overview of Scala 3.9, but a practical field report from running large-scale migrations every week. You will leave with a clear, repeatable migration strategy - and confidence that the compiler can handle more of the heavy lifting.

more great talks

Might Be Interesting

Day 1
  —  
8:00 pm
arrow pointing right icon

Scalar Afterparty

Don't miss out on this opportunity to connect with Scalar community and create lasting memories!

Day 1
  —  
3:10 pm
arrow pointing right icon

Controlled Concurrency Testing for Scala

This talk presents McCCT, a new concurrency testing tool developed at KTH by the speakers in the context of an ongoing research project.

Day 1
  —  
12:25 pm
arrow pointing right icon

Protobuf Goes Scala-First

Protobuf is commonly associated with code generation. However, in large projects with tens of thousands of message definitions, this approach can lead to an overwhelming amount of generated code. In this talk, I’ll share my journey in search of a different approach to this problem.

Day 1
  —  
4:15 pm
arrow pointing right icon

Real-Life Scala Capture Checking

This will be a live coding demonstration of Scala's newest feature set: capture checking.

Day 1
  —  
9:00 am
arrow pointing right icon

How can we trust our agents?

In my talk I will argue that we can do much better by relying in a systematic way on types and capabilities.

Day 2
  —  
3:10 pm
arrow pointing right icon

Automating API Busywork with Scala

Writing client-facing APIs involves mundane tasks, whether it be REST, GraphQL, or gRPC. In this talk, I will pick two repetitive tasks during API development and demonstrate how we can utilize Scala to automate the most boring parts.

See All Events
Join us!

We're looking for amazing speakers.
CFP is open till 10.01.2023

Fill in Call for Papers
location icon

Location

Centrum Konferencyjne POLIN, Poland
stay in touch icon

Follow Us

Contact Us