The compiler interface should expose sourcePositionMappers so that Scala 3 can render messages with the proper positions

[smarter]

steps

See scala/scala3#14691

problem

On the compiler side, we implement CompilerInterface2 in https://github.com/lampepfl/dotty/blob/main/sbt-bridge/src/dotty/tools/xsbt/CompilerBridge.java, but as far as I know this interface doesn't expose the sourcePositionMappers.

expectation

I guess we need a CompilerInterface3 with an extra argument.

notes

xsbti.compile.CompileOptions has a field sourcePositionMapper, but this class only appears in xsbti.compile.Inputs which itself only appears in xsbti.compile.IncrementalCompiler which as far as I can tell is unrelated to CompilerInterface2 (in fact I have no idea who is supposed to implement IncrementalCompiler).

[smarter]

@adpi2 If you miss working on sbt ^ :).

[tototoshi]

I had a chance to talk with @eed3si9n today. He was wondering if this issue should be resolved on the sbt side. I was also thinking about the possibility.

I have an idea. Now the position mapping using sourcePositionMappers is done by ManagedLoggedReporter in sbt. This class is provided by sbt's compilerReporter key.
If I change sbt-twirl to use compilerReporter instead of sourcePositionMapper, I think it would be possible to solve the original problem.

Unfortunately, the compilerReporter key is marked as private and cannot be replaced by the user. I don't know the reason for this and will have to look into it.