Reduce One Level of Indirection When Generating CI Tests

[khajavi]

Currently, when we want to generate CI Tests, we need to create these two sbt settings manually:

• supportedScalaVersions
• supportedJavaVersions

An example of supportedScalaVersions:

supportedScalaVersions := Map(
      (core.js / thisProject).value.id                  -> (core.js / crossScalaVersions).value,
      (core.jvm / thisProject).value.id                 -> (core.jvm / crossScalaVersions).value,
      (core.native / thisProject).value.id              -> (core.native / crossScalaVersions).value,
      (coreTests.js / thisProject).value.id             -> (coreTests.js / crossScalaVersions).value,
      (coreTests.jvm / thisProject).value.id            -> (coreTests.jvm / crossScalaVersions).value,
      (coreTests.native / thisProject).value.id         -> (coreTests.native / crossScalaVersions).value,
      ...
      ...
      ...
  )

Currently, we must manually create the supportedScalaVersions and supportedJavaVersions settings in sbt when generating CI tests. However, this approach becomes tedious and error-prone, particularly as the number of submodules increases. To address this issue, we need to develop a way to automatically generate these settings by iterating over each project and extracting its settings.

However, we cannot simply use a regular map or flatMap function to iterate over the submodules. Instead, we must leverage internal sbt functionalities and macros to achieve this. The current workaround of manually creating these settings is not a sustainable solution, and we should seek to automate this process for improved efficiency and maintainability.