Nim: asyncCheck works fine on Linux and Windows - not on Mac.

[sergiotapia]

@dom96 asked me to create a small sample illustrating the issue.

https://github.com/sergiotapia/async-check

The code runs well on Linux and Windows, the echos in the {.async} function are seen as expected.

On Mac, we see no echos, despite Jester serving responses.

nim -v
Nim Compiler Version 1.2.2 [MacOSX: amd64]
Compiled at 2020-06-25
Copyright (c) 2006-2020 by Andreas Rumpf

active boot switches: -d:release

I hope this is just an error in my code, but if it's a Nim bug I'm sure you guys will be able to tackle it. I love Nim so far!

[snej]

Reproduced this with Nim 1.2.2 on macOS 10.15.5.
Tried to reproduce with latest devel, but got a compile error in Jester. Is that library not compatible?
/Users/snej/.nimble/pkgs/jester-0.4.3/jester.nim(704, 26) Error: undeclared identifier: 'initInterval'

[Yardanico]

@snej you need jester devel for nim devel :) initInterval -> initDuration (due to removed deprecated stuff from stdlib)

[snej]

Looks like the main thread is blocked in joinThread, which is blocked in pthread_join, and not running any async tasks. Via the sample tool:

Call graph:
    1851 Thread_419617   DispatchQueue_1: com.apple.main-thread  (serial)
    + 1851 start  (in libdyld.dylib) + 1  [0x7fff71ee3cc9]
    +   1851 main  (in async_test) + 62  [0x10c36cc8e]
    +     1851 NimMain  (in async_test) + 42  [0x10c36cc4a]
    +       1851 NimMainInner  (in async_test) + 9  [0x10c36c9b9]
    +         1851 NimMainModule  (in async_test) + 590  [0x10c36cc0e]
    +           1851 serve__uyVGO9b8GZDPA7YPHmJyO1w  (in async_test) + 1557  [0x10c363115]
    +             1851 run__UlykqHUJzrYfskoCKJB7AQ  (in async_test) + 1043  [0x10c354a93]
    +               1851 joinThreads__khVjhz9bVAEzWbLJTwAvaVA  (in async_test) + 158  [0x10c2f2f7e]
    +                 1851 joinThread__b7SXibO9bv1Wvu9ani9anuO5gsystem  (in async_test) + 32  [0x10c2f2fc0]
    +                   1851 _pthread_join  (in libsystem_pthread.dylib) + 347  [0x7fff720e95c2]
    +                     1851 __ulock_wait  (in libsystem_kernel.dylib) + 10  [0x7fff7202655e]

[dom96]

Ooh, thanks for trying this out @snej. I didn't get a chance to yet.

My guess from looking at this though is that this may be a httpbeast bug. Can you try compiling with -d:useStdlib?

[sergiotapia]

If I use -d:useStdlib would that avoid using httpbeast? We're trying to determine if the bug is in that application?

[Yardanico]

@sergiotapia yes, it'll avoid using httpbeast. dom96 is trying to determine if it's a nim async bug, jester bug or httpbeast bug

[sergiotapia]

Trying now.

[sergiotapia]

@dom96 @Yardanico @snej

Using this in my nim.cfg, the applications works fine on Mac now.

-d:ssl
-d:useStdlib
--threads:on

[sergiotapia-papa]

@dom96 What should I do here? Does this mean I can't ship my app with it using httpbeast until the bug is fixed in that project?

[dom96]

Yep. What kind of app is this?

[Araq]

You can make your config conditional like so:

-d:ssl
--threads:on
@if macosx:
  # pending bug #15019 
  -d:useStdlib
@end

[sergiotapia-papa]

Thanks @Araq and @dom96

This is a small app that is meant to always be running on your machine, and regularly crawl html websites and rss feeds, and import records into a sqlite database. A self-hosted torrent search engine.

https://github.com/sergiotapia/torrentinim