Allow named pipes / FIFOs when using FileIO #25328

akka-stream/src/main/scala/akka/stream/impl/io/IOSources.scala

@@ -73,7 +73,7 @@ private[akka] final class FileSource(path: Path, chunkSize: Int, startPosition:
           // this is a bit weird but required to keep existing semantics
           if (!Files.exists(path)) throw new NoSuchFileException(path.toString)
 
-          require(Files.isRegularFile(path), s"Path '$path' is not a regular file")
+          require(!Files.isDirectory(path), s"Path '$path' is a directory")
           require(Files.isReadable(path), s"Missing read permission for '$path'")
 
           channel = FileChannel.open(path, StandardOpenOption.READ)