Adding a private lazy val introduces a binary incompability in Scala 3

[MaciejG604]

Discovered in com-lihaoyi/os-lib#239

When building with Scala 3.1.3
Changing:

package object bar {
  val foo = compute
}

to

package object bar {
  private lazy val _foo = compute
  def foo = _foo
}

Breaks binary compatibility. Is this expected?

[SethTisue]

Offhand I don't know. Have you looked at the bytecode? MiMa doesn't understand source-level constructs — it's looking at bytecode.

It would also help discussion to know: what is the complete, exact message MiMa prints? What precisely is it complaining about?

[lefou]

Here is the reported issue:

 Found 1 issue when checking against com.lihaoyi:os-lib_3:0.9.2
 * static method <clinit>()Unit in object os.package does not have a correspondent in current version
   filter with: ProblemFilter.exclude[DirectMissingMethodProblem]("os.package.<clinit>")

https://github.com/com-lihaoyi/os-lib/actions/runs/6959284130/job/18942155280