Refactor ensime-server indexer (excerpt)

SearchService.scala

// Proposed code
  override def receive: Receive = {
     // ... snip ...
      for {
        indexed <- Future.sequence(batch.map {
          case (_, f) =>
            if (!f.exists()) Future.successful(f -> Nil)
            else searchService.extractSymbolsFromClassOrJar(f).map(f ->)
        })
          .recoverWith { case t: Throwable => log.error(s"failed to index batch of ${batch.size} files", t); Future.failed(t)}

        _ <- searchService.delete(indexed.map(_._1)(collection.breakOut))
          .recoverWith { case t: Throwable => log.error(s"failed to remove stale entries in ${batch.size} files", t); Future.failed(t) }

        toPersist = indexed.filter(kv => !kv._2.isEmpty)
        _ <- Future.sequence(
          toPersist.map { kv =>
            val file = kv._1
            val syms = kv._2
            searchService.persist(FileCheck(file), syms, commitIndex = true)
              .recoverWith { case t: Throwable => log.error(s"failed to persist entries in $file", t); Future.failed(t) }
          }
        )
      } yield ()
  }
  
  
  // Original source
   override def receive: Receive = {
      // ... snip ...
      Future.sequence(batch.map {
        case (_, f) =>
          if (!f.exists()) Future.successful(f -> Nil)
          else searchService.extractSymbolsFromClassOrJar(f).map(f -> )
      }).onComplete {
        case Failure(t) =>
          log.error(s"failed to index batch of ${batch.size} files", t)
        case Success(indexed) =>
          searchService.delete(indexed.map(_._1)(collection.breakOut)).onComplete {
            case Failure(t) => log.error(s"failed to remove stale entries in ${batch.size} files", t)
            case Success(_) => indexed.collect {
              case (file, syms) if syms.isEmpty =>
              case (file, syms) =>
                searchService.persist(FileCheck(file), syms, commitIndex = true).onComplete {
                  case Failure(t) => log.error(s"failed to persist entries in $file", t)
                  case Success(_) =>
                }
            }
          }

      }
  }