No more type errors, yay!

src/main/scala-2.12/com/typesafe/sbt/PluginCompat.scala

@@ -25,4 +25,9 @@ private[sbt] object PluginCompat {
   def toNioPath(f: File)(implicit conv: FileConverter): NioPath =
     f.toPath
   def toFile(f: File)(implicit conv: FileConverter): File = f
+
+  def toFileRef(f: File)(implicit conv: FileConverter): FileRef = f
+
+  def selectFirstPredicate: Seq[FileRef] => Boolean = files =>
+    files.forall(_.isFile) && files.map(_.hashString).distinct.size == 1
 }

src/main/scala-3/com/typesafe/sbt/PluginCompat.scala

@@ -13,17 +13,23 @@ private[sbt] object PluginCompat:
   def toNioPath(a: Attributed[HashedVirtualFileRef])(using conv: FileConverter): NioPath =
     conv.toPath(a.data)
   inline def toFile(a: Attributed[HashedVirtualFileRef])(using conv: FileConverter): File =
-    toNioPath(a).toFile()
+    toNioPath(a).toFile
   def toNioPaths(cp: Seq[Attributed[HashedVirtualFileRef]])(using conv: FileConverter): Vector[NioPath] =
     cp.map(toNioPath).toVector
   inline def toFiles(cp: Seq[Attributed[HashedVirtualFileRef]])(using conv: FileConverter): Vector[File] =
-    toNioPaths(cp).map(_.toFile())
+    toNioPaths(cp).map(_.toFile)
   def toSet[A](iterable: Iterable[A]): Set[A] = iterable.to(Set)
   inline def classpathToFiles(classpath: Classpath)(using conv: FileConverter): Seq[File] =
     toFiles(classpath.to(Seq))
   inline def toKey( settingKey: SettingKey[String] ): StringAttributeKey = StringAttributeKey(settingKey.key.label)
   def toNioPath(hvf: HashedVirtualFileRef)(using conv: FileConverter): NioPath =
     conv.toPath(hvf)
   def toFile(hvf: HashedVirtualFileRef)(using conv: FileConverter): File =
-    toNioPath(hvf).toFile()
+    toNioPath(hvf).toFile
+
+  def toFileRef(file: File)(using conv: FileConverter): FileRef =
+    conv.toVirtualFile(file.toPath)
+
+  inline def selectFirstPredicate(using conv: FileConverter): Seq[FileRef] => Boolean = files =>
+    files.forall(toFile(_).isFile) && files.map(_.contentHashStr).distinct.size == 1
 end PluginCompat

src/main/scala/com/typesafe/sbt/web/SbtWeb.scala

@@ -402,10 +402,11 @@ object SbtWeb extends AutoPlugin {
    * Create package mappings for assets in the webjar format. Use the webjars path prefix and exclude all web module
    * assets.
    */
-  def createWebJarMappings: Def.Initialize[Task[Seq[(File, String)]]] = Def.task {
+  def createWebJarMappings: Def.Initialize[Task[Seq[(FileRef, String)]]] = Def.task {
     def webModule(file: File) = webModuleDirectories.value.exists(dir => IO.relativize(dir, file).isDefined)
+    implicit val fc: FileConverter = fileConverter.value
     mappings.value flatMap {
-      case (file, path) if webModule(file) => None
+      case (file, path) if webModule(toFile(file)) => None
       case (file, path)                    => Some(file -> (webJarsPathPrefix.value + path))
     }
   }
@@ -434,7 +435,8 @@ object SbtWeb extends AutoPlugin {
     if (state.value.get(disableExportedProducts).getOrElse(false)) {
       Seq.empty
     } else {
-      Seq(Attributed.blank(exportTask.value).put(toKey(webModulesLib), moduleName.value))
+      implicit val fc: FileConverter = fileConverter.value
+      Seq(Attributed.blank(toFileRef(exportTask.value)).put(toKey(webModulesLib), moduleName.value))
     }
   }
 
@@ -546,9 +548,9 @@ object SbtWeb extends AutoPlugin {
       mappings.groupBy(_._2 /*path*/ ).toSeq flatMap { grouped =>
         val (path, group) = grouped
         if (group.size > 1) {
-          val files = group.map(_._1)
+          val files = group.map(mapping => toFile(mapping._1))
           val deduplicated = firstResult(deduplicators)(files)
-          deduplicated.fold(group)(file => Seq((file, path)))
+          deduplicated.fold(group)(file => Seq((toFileRef(file), path)))
         } else {
           group
         }
@@ -563,18 +565,6 @@ object SbtWeb extends AutoPlugin {
     (fs.toStream flatMap { f => f(a).toSeq }).headOption
   }
 
-  /**
-   * Deduplicator that selects the first file contained in the base directory.
-   *
-   * @param base
-   *   the base directory to check against
-   * @return
-   *   a deduplicator function that prefers files in the base directory
-   */
-  def selectFileFrom(base: File): Deduplicator = { (files: Seq[File]) =>
-    files.find(_.relativeTo(base).isDefined)
-  }
-
   /**
    * Deduplicator that checks whether all duplicates are directories and if so will simply select the first one.
    *

src/main/scala/com/typesafe/sbt/web/package.scala

@@ -14,5 +14,5 @@ package object web {
   /**
    * A function for possibly selecting a single file from a sequence.
    */
-  type Deduplicator = Seq[FileRef] => Option[FileRef]
+  type Deduplicator = Seq[File] => Option[File]
 }