fix: Invalidate testQuick on resource file changes

**Problem**
testQuick currently does not invalidate on resource file changes.

**Solution**
This includes resource digests into the input.

main/src/main/scala/sbt/Defaults.scala

@@ -652,7 +652,14 @@ object Defaults extends BuildCommon {
       PluginDiscovery.writeDescriptors(discoveredSbtPlugins.value, resourceManaged.value)
     }).taskValue,
     managedResources := generate(resourceGenerators).value,
-    resources := Classpaths.concat(managedResources, unmanagedResources).value
+    resources := Classpaths.concat(managedResources, unmanagedResources).value,
+    resourceDigests := {
+      val uifs = (unmanagedResources / inputFileStamps).value
+      val mifs = (managedResources / inputFileStamps).value
+      (uifs ++ mifs).sortBy(_._1.toString()).map { case (p, fileStamp) =>
+        FileStamp.toDigest(p, fileStamp)
+      }
+    },
   )
   // This exists for binary compatibility and probably never should have been public.
   def addBaseSources: Seq[Def.Setting[Task[Seq[File]]]] = Nil

main/src/main/scala/sbt/Keys.scala

@@ -180,6 +180,7 @@ object Keys {
   val managedResources = taskKey[Seq[File]]("Resources generated by the build.").withRank(BTask)
   val resourceDirectories = settingKey[Seq[File]]("List of all resource directories, both managed and unmanaged.").withRank(BPlusSetting)
   val resources = taskKey[Seq[File]]("All resource files, both managed and unmanaged.").withRank(BTask)
+  private[sbt] val resourceDigests = taskKey[Seq[Digest]]("All resource files, both managed and unmanaged.").withRank(BTask)
 
   // Output paths
   @cacheLevel(include = Array.empty)

main/src/main/scala/sbt/internal/IncrementalTest.scala

@@ -49,11 +49,12 @@ object IncrementalTest:
     val cp = (Keys.test / fullClasspath).value
     val testNames = Keys.definedTests.value.map(_.name).toVector.distinct
     val converter = fileConverter.value
+    val rds = Keys.resourceDigests.value
     val extra = Keys.extraTestDigests.value
     val stamper = ClassStamper(cp, converter)
     // TODO: Potentially do something about JUnit 5 and others which might not use class name
     Map((testNames.flatMap: name =>
-      stamper.transitiveStamp(name, extra) match
+      stamper.transitiveStamp(name, extra ++ rds) match
         case Some(ts) => Seq(name -> ts)
         case None     => Nil
     ): _*)

main/src/main/scala/sbt/nio/FileStamp.scala

@@ -13,8 +13,10 @@ import java.nio.file.{ Path, Paths }
 import java.util.concurrent.ConcurrentHashMap
 
 import sbt.internal.inc.{ EmptyStamp, Stamper, Hash => IncHash, LastModified => IncLastModified }
+import sbt.internal.inc.JavaInterfaceUtil.given
 import sbt.io.IO
 import sbt.nio.file.FileAttributes
+import sbt.util.Digest
 import sjsonnew.{ Builder, JsonFormat, Unbuilder, deserializationError }
 import xsbti.compile.analysis.{ Stamp => XStamp }
 import xsbti.VirtualFileRef
@@ -103,6 +105,15 @@ object FileStamp {
   private[sbt] final case class LastModified private[sbt] (time: Long) extends FileStamp
   private[sbt] final case class Error(exception: IOException) extends FileStamp
 
+  def toDigest(path: Path, stamp: FileStamp): Digest = stamp match
+    case f: FileHashImpl =>
+      f.xstamp.getHash().toOption match
+        case Some(hash) => Digest.sha256Hash(hash.getBytes("UTF-8"))
+        case None       => Digest.sha256Hash(path)
+    case FileStamp.Hash(hex)       => Digest.sha256Hash(hex.getBytes("UTF-8"))
+    case FileStamp.Error(_)        => Digest.zero
+    case FileStamp.LastModified(_) => Digest.sha256Hash(path)
+
   object Formats {
     implicit val seqPathJsonFormatter: JsonFormat[Seq[Path]] =
       asStringArray(_.toString, Paths.get(_))

sbt-app/src/sbt-test/classloader-cache/resources/test

@@ -4,12 +4,12 @@ $ copy-file changes/updated-main.txt src/main/resources/foo.txt
 
 > run foo.txt updated-main
 
-> test
+> testQuick
 
 $ copy-file changes/updated-test.txt src/test/resources/bar.txt
 
--> test
+-> testQuick
 
 $ copy-file changes/UpdatedResourceTest.scala src/test/scala/scripted/ResourceTest.scala
 
-> test
+> testQuick