steps

Unreleased xsbti.FileChanges looks like

/** A collection of TextEdits that belong to a given URI. */
public interface FileChanges {

  /** The URI that the edits belong to. */
  URI uri();

  /** The edits belonging to the URI. */
  List<TextEdit> edits();
}

problem

At the BSP level, SourceItem is tracked as URI.

expectation

We probably should use Optional[String] and Optional[File] like we do currently in Position - https://github.com/sbt/sbt/blob/v1.9.0-RC2/internal/util-interface/src/main/java/xsbti/Position.java#L25-L27:

public interface Position {
....

  Optional<String> sourcePath();

  Optional<File> sourceFile();

notes

Inside the compiler, source files are represented as virtual SourceFiles, and currently we send information from the compiler to Zinc:

• in https://github.com/sbt/zinc/blob/v1.9.0-RC2/internal/compiler-bridge/src/main/scala/xsbt/DelegatingReporter.scala (for Scala 2.x).
• or in https://github.com/lampepfl/dotty/blob/3.3.0-RC6/sbt-bridge/src/dotty/tools/xsbt/PositionBridge.java#L83-L102 (for Scala 3.x)

using Optional[String] and Optional[File].

At the BSP server level in https://github.com/sbt/sbt/blob/v1.9.0-RC2/main/src/main/scala/sbt/internal/server/BuildServerReporter.scala we already know the association between source files and problems (after the compilation is done), and BSP server also knows how to convert the source file into URI that it told the BSP client.