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13489 :: malebolgia dosen't work along with zero_functional (SIGSEGV)

• aj3423 (orginal) [2025-11-02T00:10:53+01:00] view original

  The following program uses both malebolgia and zero_funcional, it crashes. I don't know which one causes the problem because:

  • zero_functional works fine if I replace malebolgia with nim-taskpools or asyncdispatch.
  • malebolgia works fine if I use sequtils.mapIt instead of zero_functional.map.

  But they just don't work along with each other.

  
  import malebolgia
  # import taskpools
  import zero_functional
  
  type
    Boss* = ref object of RootObj
      name*: string
    
    Task* = ref object
      fromBoss*: string
  
  proc generateTasks*(boss: Boss): seq[Task] =
    
    return @["dummy_string"] -->>
      map(Task(
        fromBoss: boss.name,
      ))
  
  
  proc working(ds: ptr Boss) =
    discard ds[].generateTasks()
  
  
  proc main() =
    
    let boss = Boss()
    
    
    # crashes with malebolgia
    var tasks: seq[Task]
    var m = createMaster()
    m.awaitAll:
      m.spawn working(addr boss)
    
    # Taskpool works fine
    # var pool = Taskpool.new(5)
    # pool.spawn working(addr boss)
    # pool.syncAll()
    # pool.shutdown()
  
  main()
  Run

  The error:

  
  Building test/test using c backend
        Info: compiling nim package using /root/.local/share/grabnim/current/bin/nim
   Nim Output # test.nim:15
          ... # @["dummy_string"].zfun:
          ... #   map(Task(fromBoss: boss.name))
          ... (proc (): auto =
          ...   {.push, hint[XDeclaredButNotUsed]: off.}
          ...   proc iterType(): auto =
          ...     for it0 in @["dummystring"]:
          ...       let it1 = when compiles(Task(fromBoss: boss.name)(it0)):
          ...         Task(fromBoss: boss.name)(it0)
          ...       else:
          ...         Task(fromBoss: boss.name)
          ...       result = (it0, it1)
          ...   {.pop.}
          ...   var res: seq[type(iterType()[1])]
          ...   result = zfInit(res)
          ...   for it0 in @["dummystring"]:
          ...     let it1 = when compiles(Task(fromBoss: boss.name)(it0)):
          ...       Task(fromBoss: boss.name)(it0)
          ...     else:
          ...       Task(fromBoss: boss.name)
          ...     zfAddItemChk(result, -1, it1, "seq[string]", "", false))()
  Traceback (most recent call last)
  /run/media/root/e/nim/4/src/test.nim(41) test
  /run/media/root/e/nim/4/src/test.nim(12) main
  /root/.local/share/grabnim/nim-devel/lib/system/orc.nim(527) nimDecRefIsLastCyclicDyn
  /root/.local/share/grabnim/nim-devel/lib/system/orc.nim(509) rememberCycle
  /root/.local/share/grabnim/nim-devel/lib/system/orc.nim(156) unregisterCycle
  SIGSEGV: Illegal storage access. (Attempt to read from nil?)
  Run

  The above code is generated by the debugging operator -->> from `zero_functional, I think it will be simplified to:

  
  @[Task(fromBoss: boss.name)]
  Run

  So I don't see any problem here.

  Any idea what causes the problem? I know how to work around it, but how to fix it (or them)?

  Nim version: 2.3.1 devel OS: Linux

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• Araq (orginal) [2025-11-02T05:40:42+01:00] view original

  Reduce your program further so that zero_functional is not involved but your program dies the same way. Then the problem should be easier to spot.

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• aj3423 (orginal) [2025-11-02T07:31:13+01:00] view original

  zero_functional is removed, its macro can be simplified to this:

  
  import malebolgia
  
  type
    Boss* = ref object of RootObj
      name*: string
    
    Task* = ref object
      fromBoss*: string
  
  proc generateTasks*(boss: Boss): Task =
    return (proc (): Task =
      result = Task(fromBoss: boss.name)
    )()
  
  
  proc working(ds: ptr Boss) =
    discard ds[].generateTasks()
  
  
  proc main() =
    let boss = Boss()
    
    var tasks: Task
    
    var m = createMaster()
    m.awaitAll:
      m.spawn working(addr boss)
  
  main()
  
  Run

  It seems to be caused by the closure return (proc (): .... It can't be simplified further, it doesn't crash if anything else is removed.

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• Araq (orginal) [2025-11-02T08:10:45+01:00] view original

  What happens if you replace malebolgia with createThread? I bet the crash persists.

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• aj3423 (orginal) [2025-11-02T08:37:16+01:00] view original

  Yes, createThread also crashes:

  
  proc main() =
    let boss = Boss()
    
    var t: Thread[ptr Boss]
    createThread(t, working, addr boss)
    joinThread(t)
  Run

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• Araq (orginal) [2025-11-02T09:18:02+01:00] view original

  Well now you can report it on github as the test has no dependencies! :-)

  It's either an ORC bug or a subtle mistake on your part, I don't know yet.

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• aj3423 (orginal) [2025-11-02T12:29:49+01:00] view original

  Aha, will do, thank you.

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