GraalVM native-image with Scala 3 reflection hell

This page summarizes the projects mentioned and recommended in the original post on reddit.com/r/scala
#Scala #Tools #native-image #SBT #Scala3

Our great sponsors
  • SonarLint - Deliver Cleaner and Safer Code - Right in Your IDE of Choice!
  • Scout APM - Less time debugging, more time building
  • SaaSHub - Software Alternatives and Reviews
Our great sponsors

  • sbt-native-image

    Plugin to generate native-image binaries with sbt

    The reason seems to be Scala 3's new encoding for lazy vals, where a reflective access to a variable called bitmap takes place. To demonstrate this, I took the http4s g8 template, set it up with Scala 3.1.0, added sbt native-image, started the nativeImageRunAgent and ran a single request against GET /joke. After stopping the server, the native-image run agent generated the reflective configs that are required for this path of execution. Comparing the generated Scala 2.13 with the Scala 3 configs, yields a bloated version for Scala 3 that contains these additional rules:

  • scala-3-lazy-reflective-access

    Showcase of GraalVM native-image's configuration bloating up with Scala 3

    Here is the sample code, based on the http4s g8 template: https://github.com/taig/scala-3-lazy-reflective-access

  • SonarLint

    Deliver Cleaner and Safer Code - Right in Your IDE of Choice!. SonarLint is a free and open source IDE extension that identifies and catches bugs and vulnerabilities as you code, directly in the IDE. Install from your favorite IDE marketplace today.

  • dotty

    The Scala 3 compiler, also known as Dotty.

    See https://github.com/lampepfl/dotty/issues/13985, maybe the graalvm reflection config format could be enriched to support wildcards if it doesn't already?

NOTE: The number of mentions on this list indicates mentions on common posts plus user suggested alternatives. Hence, a higher number means a more popular project.

Suggest a related project

Related posts