xsbti.Position: add startOffset and endOffset

A position now has a start, an end, and a point (the existing `offset`),
just like it does in the Scala compiler. This information is especially
useful for displaying squiggly lines in an IDE.

This commit and the next one are required for https://github.com/sbt/zinc/pull/571

build.sbt

@@ -124,6 +124,8 @@ lazy val utilLogging = (project in internalPath / "util-logging")
       exclude[DirectMissingMethodProblem]("sbt.internal.util.SuccessEvent.copy*"),
       exclude[DirectMissingMethodProblem]("sbt.internal.util.TraceEvent.copy*"),
       exclude[DirectMissingMethodProblem]("sbt.internal.util.StringEvent.copy*"),
+      // Private final class constructor changed
+      exclude[DirectMissingMethodProblem]("sbt.util.InterfaceUtil#ConcretePosition.this"),
     ),
   )
   .configure(addSbtIO)

internal/util-interface/src/main/java/xsbti/Position.java

@@ -18,4 +18,8 @@ public interface Position
 
 	Optional<String> sourcePath();
 	Optional<File> sourceFile();
+
+	// Default values to avoid breaking binary compatibility
+	default Optional<Integer> startOffset() { return Optional.empty(); }
+	default Optional<Integer> endOffset() { return Optional.empty(); }
 }

internal/util-logging/src/main/scala/sbt/util/InterfaceUtil.scala

@@ -36,6 +36,7 @@ object InterfaceUtil {
       case None    => Optional.empty[A]()
     }
 
+  // Overload to preserve binary compatibility
   def position(
       line0: Option[Integer],
       content: String,
@@ -45,7 +46,28 @@ object InterfaceUtil {
       sourcePath0: Option[String],
       sourceFile0: Option[File]
   ): Position =
-    new ConcretePosition(line0, content, offset0, pointer0, pointerSpace0, sourcePath0, sourceFile0)
+    position(line0, content, offset0, pointer0, pointerSpace0, sourcePath0, sourceFile0, None, None)
+
+  def position(
+      line0: Option[Integer],
+      content: String,
+      offset0: Option[Integer],
+      pointer0: Option[Integer],
+      pointerSpace0: Option[String],
+      sourcePath0: Option[String],
+      sourceFile0: Option[File],
+      startOffset0: Option[Integer],
+      endOffset0: Option[Integer]
+  ): Position =
+    new ConcretePosition(line0,
+                         content,
+                         offset0,
+                         pointer0,
+                         pointerSpace0,
+                         sourcePath0,
+                         sourceFile0,
+                         startOffset0,
+                         endOffset0)
 
   def problem(cat: String, pos: Position, msg: String, sev: Severity): Problem =
     new ConcreteProblem(cat, pos, msg, sev)
@@ -75,7 +97,9 @@ object InterfaceUtil {
       pointer0: Option[Integer],
       pointerSpace0: Option[String],
       sourcePath0: Option[String],
-      sourceFile0: Option[File]
+      sourceFile0: Option[File],
+      startOffset0: Option[Integer],
+      endOffset0: Option[Integer]
   ) extends Position {
     val line = o2jo(line0)
     val lineContent = content
@@ -84,6 +108,8 @@ object InterfaceUtil {
     val pointerSpace = o2jo(pointerSpace0)
     val sourcePath = o2jo(sourcePath0)
     val sourceFile = o2jo(sourceFile0)
+    override val startOffset = o2jo(startOffset0)
+    override val endOffset = o2jo(endOffset0)
   }
 
   private final class ConcreteProblem(