New PkgEval failures after merging #42339 ([Distributed] Worker local race condition between put! and fetch for Futures)

[KristofferC]

Putting this on the 1.8 milestone so it is not forgotten.

#42339 (comment)

[krynju]

Seems like some issue with unwrapping nothing values specifically.
I'll try to investigate/fix it this weekend

Here's an MWE:

julia> using Distributed

julia> addprocs(1)
1-element Vector{Int64}:
 2

julia> fetch(remotecall(() -> 10, 2))
10

julia> fetch(remotecall(() -> nothing, 2))
ERROR: ArgumentError: No value arguments present
Stacktrace:
 [1] something()
   @ Base .\some.jl:99   
 [2] something(::Nothing)
   @ Base .\some.jl:100  
 [3] fetch(r::Future)    
   @ Distributed C:\cygwin64\home\krynjupc\julia\usr\share\julia\stdlib\v1.8\Distributed\src\remotecall.jl:638
 [4] top-level scope
   @ REPL[3]:1

[krynju]

Ok this was actually a simple one. I overlooked the return logic in fetch and was attempting to do something(nothing) at some point in code

Here's the PR #43398

[Sacha0]

Thanks Krystian! :)