parafib error: MPSC channel size was 512

[lessneek]

$ nim -v                          
Nim Compiler Version 1.1.1 [Linux: amd64]
Compiled at 2020-02-08
Copyright (c) 2006-2019 by Andreas Rumpf

active boot switches: -d:release

parafib.nim:

import weave

proc fib(n: int): int =
  # int64 on x86-64
  if n < 2:
    return n

  let x = spawn fib(n-1)
  let y = fib(n-2)

  result = sync(x) + y

proc main() =
  var n = 20

  init(Weave)
  let f = fib(n)
  exit(Weave)

  echo f

main()

nim c --threads:on ./parafib.nim

Error: unhandled exception: ~/.nimble/pkgs/weave-0.1.0/weave/memory/memory_pools.nim(625, 8) `sizeof(ChannelMpscUnboundedBatch[ptr MemBlock]) == 272` MPSC channel size was 512 [AssertionError]

[mratsim]

Works for me on one of the commits from yesterday, will try updating to see if there is a regression.
Was your compiler installed through choosenim?

[mratsim]

Recompiled on the latest commit, it still works

My guess is that somehow the compiler you compiled on 2020-02-08 was from before:

• PR: {.align.} pragma is not applied if there is a generic field nim-lang/Nim#13122
• commit: nim-lang/Nim@abea803

[mratsim]

Sorry, actually the issue is the following:

• you are using Weave 0.1.0, it is not compatible with the devel from after commit nim-lang/Nim@abea803
• You need to install Weave devel as well: nimble install weave@#master for compatibility with the latest Nim devel.