Fix not enough memory on i386. (#467)

* Fix waitFor() should not exit earlier last callback will be scheduled.

* Tune tests to use less memory.

* Fix `testutils`. There is no more last poll() needed.

* Update chronos/internal/asyncfutures.nim

---------

Co-authored-by: Jacek Sieka <jacek@status.im>

chronos/internal/asyncfutures.nim

@@ -560,9 +560,13 @@ proc waitFor*[T](fut: Future[T]): T {.raises: [CatchableError].} =
   ## **Blocks** the current thread until the specified future finishes and
   ## reads it, potentially raising an exception if the future failed or was
   ## cancelled.
-  while not(fut.finished()):
-    poll()
-
+  var finished = false
+  # Ensure that callbacks currently scheduled on the future run before returning
+  proc continuation(udata: pointer) {.gcsafe.} = finished = true
+  if not(fut.finished()):
+    fut.addCallback(continuation)
+    while not(finished):
+      poll()
   fut.read()
 
 proc asyncSpawn*(future: Future[void]) =

tests/testfut.nim

@@ -54,7 +54,6 @@ suite "Future[T] behavior test suite":
     fut.addCallback proc(udata: pointer) =
       testResult &= "5"
     discard waitFor(fut)
-    poll()
 
     check:
       fut.finished
@@ -80,7 +79,6 @@ suite "Future[T] behavior test suite":
     fut.addCallback cb5
     fut.removeCallback cb3
     discard waitFor(fut)
-    poll()
     check:
       fut.finished
       testResult == "1245"
@@ -1260,12 +1258,12 @@ suite "Future[T] behavior test suite":
         (loc.procedure == procedure)
 
     check:
-      chk(loc10, "testfut.nim", 1227, "macroFuture")
-      chk(loc11, "testfut.nim", 1230, "")
-      chk(loc20, "testfut.nim", 1239, "template")
-      chk(loc21, "testfut.nim", 1242, "")
-      chk(loc30, "testfut.nim", 1236, "procedure")
-      chk(loc31, "testfut.nim", 1243, "")
+      chk(loc10, "testfut.nim", 1225, "macroFuture")
+      chk(loc11, "testfut.nim", 1228, "")
+      chk(loc20, "testfut.nim", 1237, "template")
+      chk(loc21, "testfut.nim", 1240, "")
+      chk(loc30, "testfut.nim", 1234, "procedure")
+      chk(loc31, "testfut.nim", 1241, "")
 
   asyncTest "withTimeout(fut) should wait cancellation test":
     proc futureNeverEnds(): Future[void] =

tests/testhttpclient.nim

@@ -187,11 +187,11 @@ suite "HTTP client testing suite":
     let ResponseTests = [
       (MethodGet, "/test/short_size_response", 65600, 1024,
        "SHORTSIZERESPONSE"),
-      (MethodGet, "/test/long_size_response", 262400, 1024,
+      (MethodGet, "/test/long_size_response", 131200, 1024,
        "LONGSIZERESPONSE"),
       (MethodGet, "/test/short_chunked_response", 65600, 1024,
        "SHORTCHUNKRESPONSE"),
-      (MethodGet, "/test/long_chunked_response", 262400, 1024,
+      (MethodGet, "/test/long_chunked_response", 131200, 1024,
        "LONGCHUNKRESPONSE")
     ]
     proc process(r: RequestFence): Future[HttpResponseRef] {.

tests/testproc.bat

@@ -34,7 +34,7 @@ ping -n 10 127.0.0.1 > NUL
 EXIT 0
 
 :BIGDATA
-FOR /L %%G IN (1, 1, 400000) DO ECHO ALICEWASBEGINNINGTOGETVERYTIREDOFSITTINGBYHERSISTERONTHEBANKANDO
+FOR /L %%G IN (1, 1, 100000) DO ECHO ALICEWASBEGINNINGTOGETVERYTIREDOFSITTINGBYHERSISTERONTHEBANKANDO
 EXIT 0
 
 :ENVTEST

tests/testproc.nim

@@ -214,9 +214,9 @@ suite "Asynchronous process management test suite":
         "tests/testproc.sh bigdata"
     let expect =
       when defined(windows):
-        400_000 * (64 + 2)
+        100_000 * (64 + 2)
       else:
-        400_000 * (64 + 1)
+        100_000 * (64 + 1)
     let process = await startProcess(command, options = options,
                                      stdoutHandle = AsyncProcess.Pipe,
                                      stderrHandle = AsyncProcess.Pipe)

tests/testproc.sh

@@ -12,7 +12,7 @@ elif [ "$1" == "timeout2" ]; then
 elif [ "$1" == "timeout10" ]; then
   sleep 10
 elif [ "$1" == "bigdata" ]; then
-  for i in {1..400000}
+  for i in {1..100000}
   do
     echo "ALICEWASBEGINNINGTOGETVERYTIREDOFSITTINGBYHERSISTERONTHEBANKANDO"
   done

tests/testutils.nim

@@ -75,11 +75,6 @@ suite "Asynchronous utilities test suite":
         pendingFuturesCount() == 2'u
 
       waitFor fut
-      check:
-        getCount() == 1'u
-        pendingFuturesCount() == 1'u
-
-      poll()
       check:
         getCount() == 0'u
         pendingFuturesCount() == 0'u