fix: shorten diagnostic ranges for scala-cli

Previously, all diagnostic ranges where implicitly expanded to the
start/end of a token which meant that scala-cli dependency update
diagnostics would span a whole line which could possibly be misleading
if multiple dependencies where specified on the same line.

metals/src/main/scala/scala/meta/internal/metals/Diagnostics.scala

@@ -260,25 +260,30 @@ final class Diagnostics(
       d: Diagnostic,
       snapshot: Input,
   ): Option[Diagnostic] = {
-    val result = edit.toRevised(d.getRange).map { range =>
-      val ld = new l.Diagnostic(
-        range,
-        d.getMessage,
-        d.getSeverity,
-        d.getSource,
+    val result = edit
+      .toRevised(
+        range = d.getRange,
+        adjustWithinToken = d.getSource() == "scala-cli",
       )
-      // Scala 3 sets the diagnostic code to -1 for NoExplanation Messages. Ideally
-      // this will change and we won't need this check in the future, but for now
-      // let's not forward them.
-      if (
-        d.getCode() != null && d
-          .getCode()
-          .isLeft() && d.getCode().getLeft() != "-1"
-      )
-        ld.setCode(d.getCode())
-      ld.setData(d.getData)
-      ld
-    }
+      .map { range =>
+        val ld = new l.Diagnostic(
+          range,
+          d.getMessage,
+          d.getSeverity,
+          d.getSource,
+        )
+        // Scala 3 sets the diagnostic code to -1 for NoExplanation Messages. Ideally
+        // this will change and we won't need this check in the future, but for now
+        // let's not forward them.
+        if (
+          d.getCode() != null && d
+            .getCode()
+            .isLeft() && d.getCode().getLeft() != "-1"
+        )
+          ld.setCode(d.getCode())
+        ld.setData(d.getData)
+        ld
+      }
     if (result.isEmpty) {
       d.getRange.toMeta(snapshot).foreach { pos =>
         val message = pos.formatMessage(

metals/src/main/scala/scala/meta/internal/parsing/TokenEditDistance.scala

@@ -27,8 +27,15 @@ sealed trait TokenEditDistance {
    * - it should only return `None` in the case when the sources don't tokenize.
    *   When the original token is removed in the revised document, we find instead the
    *   nearest token in the original document instead.
+   *
+   * If `adjustWithinToken` is true and the original and revised range are both contained within
+   * a single (matching) token, then adjust the returned range to match the start/end offsets of
+   * the input range with respect to the token.
    */
-  def toRevised(range: l.Range): Option[l.Range]
+  def toRevised(
+      range: l.Range,
+      adjustWithinToken: Boolean = false,
+  ): Option[l.Range]
   def toRevised(originalOffset: Int): Either[EmptyResult, Position]
   def toRevised(
       originalLine: Int,
@@ -94,7 +101,10 @@ sealed trait TokenEditDistance {
 object TokenEditDistance {
 
   case object Unchanged extends TokenEditDistance {
-    def toRevised(range: l.Range): Option[l.Range] = Some(range)
+    def toRevised(
+        range: l.Range,
+        adjustWithinToken: Boolean = false,
+    ): Option[l.Range] = Some(range)
     def toRevised(originalOffset: Int): Either[EmptyResult, Position] =
       EmptyResult.unchanged
     def toRevised(
@@ -116,7 +126,10 @@ object TokenEditDistance {
   }
 
   case object NoMatch extends TokenEditDistance {
-    def toRevised(range: l.Range): Option[l.Range] = None
+    def toRevised(
+        range: l.Range,
+        adjustWithinToken: Boolean = false,
+    ): Option[l.Range] = None
     def toRevised(originalOffset: Int): Either[EmptyResult, Position] =
       EmptyResult.noMatch
     def toRevised(
@@ -145,7 +158,10 @@ object TokenEditDistance {
       extends TokenEditDistance {
 
     private val logger: Logger = Logger.getLogger(this.getClass.getName)
-    def toRevised(range: l.Range): Option[l.Range] = {
+    def toRevised(
+        range: l.Range,
+        adjustWithinToken: Boolean = false,
+    ): Option[l.Range] = {
       range.toMeta(originalInput).flatMap { pos =>
         val matchingTokens = matching.lift
 
@@ -216,7 +232,10 @@ object TokenEditDistance {
                 val offset = end.revised.start
                 Position.Range(revisedInput, offset - 1, offset)
               } else if (start.revised == end.revised) {
-                start.revised.pos
+                // new range spans one token
+                if (adjustWithinToken)
+                  computeAdjustmentWithinToken(range, start)
+                else start.revised.pos
               } else {
                 val endOffset = end.revised match {
                   case t if t.isLF => t.start
@@ -271,6 +290,28 @@ object TokenEditDistance {
       else if (pos.end <= offset) BinarySearch.Smaller
       else BinarySearch.Greater
 
+    private def computeAdjustmentWithinToken(
+        original: l.Range,
+        matching: MatchingToken[A],
+    ): Position.Range = {
+      val originalStartPositionOpt: Option[Position] =
+        original.getStart().toMeta(originalInput)
+      val originalEndPositionOpt: Option[Position] =
+        original.getEnd().toMeta(originalInput)
+
+      // Original start range - start of the found token
+      val startCorrection =
+        originalStartPositionOpt.fold(0)(_.start - matching.original.start)
+      val endCorrection =
+        originalEndPositionOpt.fold(0)(matching.original.end - _.end)
+
+      Position.Range(
+        revisedInput,
+        matching.revised.start + startCorrection,
+        matching.revised.end - endCorrection,
+      )
+    }
+
     override def toString(): String = s"Diff(${matching.length} tokens)"
   }
 

tests/slow/src/main/scala/tests/scalacli/BaseScalaCLIActionSuite.scala

@@ -8,6 +8,46 @@ import tests.codeactions.BaseCodeActionLspSuite
 class BaseScalaCLIActionSuite(name: String)
     extends BaseCodeActionLspSuite(name) {
 
+  def checkNoActionScalaCLI(
+      name: TestOptions,
+      input: String,
+      expectNoDiagnostics: Boolean = true,
+      kind: List[String] = Nil,
+      scalafixConf: String = "",
+      scalacOptions: List[String] = Nil,
+      scalaCliOptions: List[String] = Nil,
+      configuration: => Option[String] = None,
+      scalaVersion: String = scalaVersion,
+      renamePath: Option[String] = None,
+      extraOperations: => Unit = (),
+      fileName: String = "A.scala",
+      changeFile: String => String = identity,
+      expectError: Boolean = false,
+      filterAction: CodeAction => Boolean = _ => true,
+  ): Unit = {
+    val fileContent = input.replace("<<", "").replace(">>", "")
+
+    checkScalaCLI(
+      name = name,
+      input = input,
+      expectedActions = "",
+      expectedCode = fileContent,
+      expectNoDiagnostics = expectNoDiagnostics,
+      kind = kind,
+      scalaCliOptions = scalaCliOptions,
+      configuration = configuration,
+      scalaVersion = scalaVersion,
+      scalafixConf = scalafixConf,
+      scalacOptions = scalacOptions,
+      renamePath = renamePath,
+      extraOperations = extraOperations,
+      fileName = fileName,
+      changeFile = changeFile,
+      expectError = expectError,
+      filterAction = filterAction,
+    )
+  }
+
   def checkScalaCLI(
       name: TestOptions,
       input: String,

tests/slow/src/test/scala/tests/scalacli/ScalaCliActionsSuite.scala

@@ -20,7 +20,7 @@ class ScalaCliActionsSuite
 
   checkScalaCLI(
     "actionable-diagnostic-update",
-    s"""|//> <<>>using lib "com.lihaoyi::os-lib:${oldOsLibVersion.repr}"
+    s"""|//> using lib "<<>>com.lihaoyi::os-lib:${oldOsLibVersion.repr}"
         |
         |object Hello extends App {
         |  println("Hello")
@@ -37,6 +37,18 @@ class ScalaCliActionsSuite
     expectNoDiagnostics = false,
   )
 
+  checkNoActionScalaCLI(
+    "actionable-diagnostic-out-of-range",
+    s"""|//> <<>>using lib "com.lihaoyi::os-lib:${oldOsLibVersion.repr}"
+        |
+        |object Hello extends App {
+        |  println("Hello")
+        |}
+        |""".stripMargin,
+    scalaCliOptions = List("--actions", "-S", scalaVersion),
+    expectNoDiagnostics = false,
+  )
+
   checkScalaCLI(
     "auto-import",
     s"""|//> using scala "${BuildInfo.scala213}"