I joined Lightbend (then Typesafe) in March, 2014. After six incredible years April 7, 2020 was my last day at Lightbend. I am grateful that I got the opportunity to work with an amazing group of people at Lightbend, partners, customers, and various people I got to meet at conferences. Looking back, before COVID-19 times, it's almost surreal that I was flying to Europe, Asia, and North America every few months to attend conferences and tech meetings.

Last week I wrote about #8820, my proposal to add user-land compiler warnings in Scala. The example I had was implementing ApiMayChange annotation. This was ok as a start, but a bit verbose. If we want some API status to be used frequently, it would be cool if library authors could define their own status annotation. We're going to look into doing that today.

You know those big napa cabbage no one is probably buying?

They make a tasty stew called 扁炉 (bianlu or "pienlo") supposedly from Guangxi region in China, and has a cult following in Japan. I make a vegetarian version of it.

As a library author, I've been wanting to tag methods in Scala that can trigger custom warnings or compiler errors. Why would I want to intentionally cause a compiler error? One potential use case is displaying a migration message for a removed API. A week ago, I sent #8820 to scala/scala proposing the idea of @apiStatus that enables user-land compiler warnings and errors.

Spotify: https://open.spotify.com/playlist/0PHmoJCo6yesLCHC1cFaBJ?si=mg6tqCRYTzWx...
YouTube: https://www.youtube.com/playlist?list=PLSUh6oJ5ZotVTZp7NrT2vq7Y9npLmn1ty
4h 35m

The relationship given to Int and Long should be exactly the same as the relationship third-party library like Spire can write UInt or Rational with the first-class numeric types.

• We should make 1 == 1L an error under strictEquality
• We should allow custom types to participate in constant expression conversion using FromDigits

• Scala 2.x uses universal equality which allows comparison of Int and String. Dotty introduces "multiversal" strictEquality that works similar to Eq typeclass.
• Currently both Scala 2.x and Dotty use Java's == to compare unboxed primitive types. This mixes comparison of Int with Float and Double etc.
• Float is narrower than Int, and Double is narrower than Long.
• Because Scala transparently boxes Int into java.lang.Integer as (1: Any), it implements cooperative equality for == and ##, but not for equals and hashCode, which emulates widening for boxed primitive types. Many people are unaware of this behavior, and this could lead to surprising bugs if people believed that equals is same as ==.
• We might be able to remove cooperative equality if we are willing to make unboxed primitive comparison of different types 1L == 1 an error.

giter8.version

I added a small app called giter8-launcher for Giter8 0.12.0. The purpose of the app is to make the behavior of the Giter8 template more predictable. Today, template authors may create a template for some version of Giter8 X, but the users might use some other version of Giter8 Y that ships with "sbt new."

Spotify: https://open.spotify.com/playlist/2EHJoRDsHC7SADeMGP2UDk?si=pgypMooVTQ-s...
YouTube: https://www.youtube.com/playlist?list=PLSUh6oJ5ZotXojw-eMeoubAGXM3mF23SJ
3h 38m

This is part 2 of the post about sbt-projectmatrix, an experimental plugin that I've been working to improve the cross building in sbt. Here's part 1. I've just released 0.4.0.

• sbt-projectmatrix enables parallel building of multiple Scala versions and JVM/JS/Native cross building.
• VirtualAxis allows flexible inter-matrix dependencies between Scala-Java matrix, and custom cross-library axis.