Merge pull request #2972 from armanbilge/fix/js-write-writable-hang-on-end

Fix hanging in `writeWritable` on unacked 'end'

Author: mpilquist

io/js/src/main/scala/fs2/io/ioplatform.scala

@@ -158,13 +158,18 @@ private[fs2] trait ioplatform {
             case None => Pull.done
           }
 
-          go(in).stream.onFinalizeCase[F] {
-            case Resource.ExitCase.Succeeded =>
-              if (endAfterUse)
+          val end =
+            if (endAfterUse)
+              Stream.exec {
                 F.async_[Unit] { cb =>
                   writable.end(e => cb(e.toLeft(()).leftMap(js.JavaScriptException)))
                 }
-              else F.unit
+              }
+            else Stream.empty
+
+          (go(in).stream ++ end).onFinalizeCase[F] {
+            case Resource.ExitCase.Succeeded =>
+              F.unit
             case Resource.ExitCase.Errored(_) | Resource.ExitCase.Canceled =>
               // tempting, but don't propagate the error!
               // that would trigger a unhandled Node.js error that circumvents FS2/CE error channels

io/js/src/test/scala/fs2/io/IoPlatformSuite.scala

@@ -27,6 +27,8 @@ import fs2.Fs2Suite
 import fs2.io.internal.facade
 import org.scalacheck.effect.PropF.forAllF
 
+import scala.concurrent.duration._
+
 class IoPlatformSuite extends Fs2Suite {
 
   test("to/read Readable") {
@@ -92,4 +94,25 @@ class IoPlatformSuite extends Fs2Suite {
     }.attempt
   }
 
+  test("unacknowledged 'end' does not prevent writeWritable cancelation") {
+    val writable = IO {
+      new facade.stream.Duplex(
+        new facade.stream.DuplexOptions {
+          var autoDestroy = false
+          var read = _ => ()
+          var write = (_, _, _, _) => ()
+          var `final` = (_, _) => ()
+          var destroy = (_, _, _) => ()
+        }
+      )
+    }
+
+    Stream
+      .empty[IO]
+      .through(writeWritable[IO](writable))
+      .compile
+      .drain
+      .timeoutTo(100.millis, IO.unit)
+  }
+
 }