From 1eb834a2f98c31677e899ffcc80259a10d78cfe7 Mon Sep 17 00:00:00 2001
From: Eugene Kabanov <eugene.kabanov@status.im>
Date: Tue, 5 Mar 2024 18:33:46 +0200
Subject: [PATCH] Fix `or` deadlock issue. (#517)

* Fix `or` should not create future with OwnCancelSchedule flag set.

* Fix `CancelledError` missing from raises list when both futures has empty raises list.

* Fix macros tests.
---
 chronos/internal/asyncfutures.nim |  9 ++++-----
 tests/testbugs.nim                | 13 +++++++++++++
 tests/testmacro.nim               |  2 +-
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/chronos/internal/asyncfutures.nim b/chronos/internal/asyncfutures.nim
index 1a2be757..de6debaf 100644
--- a/chronos/internal/asyncfutures.nim
+++ b/chronos/internal/asyncfutures.nim
@@ -786,7 +786,7 @@ template orImpl*[T, Y](fut1: Future[T], fut2: Future[Y]): untyped =
   fut2.addCallback(cb)
 
   retFuture.cancelCallback = cancellation
-  return retFuture
+  retFuture
 
 proc `or`*[T, Y](fut1: Future[T], fut2: Future[Y]): Future[void] =
   ## Returns a future which will complete once either ``fut1`` or ``fut2``
@@ -801,7 +801,7 @@ proc `or`*[T, Y](fut1: Future[T], fut2: Future[Y]): Future[void] =
   ## completed, the result future will also be completed.
   ##
   ## If cancelled, ``fut1`` and ``fut2`` futures WILL NOT BE cancelled.
-  var retFuture = newFuture[void]("chronos.or")
+  var retFuture = newFuture[void]("chronos.or()")
   orImpl(fut1, fut2)
 
 
@@ -1665,10 +1665,9 @@ proc `or`*[T, Y, E1, E2](
     fut1: InternalRaisesFuture[T, E1],
     fut2: InternalRaisesFuture[Y, E2]): auto =
   type
-    InternalRaisesFutureRaises = union(E1, E2)
+    InternalRaisesFutureRaises = union(E1, E2).union((CancelledError,))
 
-  let
-    retFuture = newFuture[void]("chronos.wait()", {FutureFlag.OwnCancelSchedule})
+  let retFuture = newFuture[void]("chronos.or()", {})
   orImpl(fut1, fut2)
 
 proc wait*(fut: InternalRaisesFuture, timeout = InfiniteDuration): auto =
diff --git a/tests/testbugs.nim b/tests/testbugs.nim
index fc4af3a4..3f2f4e42 100644
--- a/tests/testbugs.nim
+++ b/tests/testbugs.nim
@@ -135,6 +135,16 @@ suite "Asynchronous issues test suite":
     await server.closeWait()
     return true
 
+  proc testOrDeadlock(): Future[bool] {.async.} =
+    proc f(): Future[void] {.async.} =
+      await sleepAsync(2.seconds) or sleepAsync(1.seconds)
+    let fx = f()
+    try:
+      await fx.cancelAndWait().wait(2.seconds)
+    except AsyncTimeoutError:
+      return false
+    true
+
   test "Issue #6":
     check waitFor(issue6()) == true
 
@@ -152,3 +162,6 @@ suite "Asynchronous issues test suite":
 
   test "IndexError crash test":
     check waitFor(testIndexError()) == true
+
+  test "`or` deadlock [#516] test":
+    check waitFor(testOrDeadlock()) == true
diff --git a/tests/testmacro.nim b/tests/testmacro.nim
index 9b19c689..d646303a 100644
--- a/tests/testmacro.nim
+++ b/tests/testmacro.nim
@@ -491,7 +491,7 @@ suite "Exceptions tracking":
     proc testit2 {.async: (raises: [IOError]).} =
       raise (ref IOError)()
 
-    proc test {.async: (raises: [ValueError, IOError]).} =
+    proc test {.async: (raises: [CancelledError, ValueError, IOError]).} =
       await testit() or testit2()
 
     proc noraises() {.raises: [].} =