Make accesses to __iNtErNaL_running_procs thread-safe

[giordano]

__iNtErNaL_running_procs is a global state, and in a multi-threaded scenario it's unsafe to directly push! to it. A simple lock around it solves the issue. Without this, I got occasional

  Got exception outside of a @test
  TaskFailedException
      nested task error: AssertionError: Multiple concurrent writes to Dict detected!
      Stacktrace:
        [1] rehash!(h::Dict{Base.Process, Nothing}, newsz::Int64)
          @ Base ./dict.jl:183
        [2] ht_keyindex2_shorthash!(h::Dict{Base.Process, Nothing}, key::Base.Process)
          @ Base ./dict.jl:270
        [3] setindex!(h::Dict{Base.Process, Nothing}, v0::Nothing, key::Base.Process)
          @ Base ./dict.jl:358
        [4] push!
          @ ./set.jl:137 [inlined]
        [5] Malt.Worker(; env::Vector{Pair{String, String}}, exename::String, exeflags::Vector{String}, monitor_stdout::Bool, monitor_stderr::Bool)
          @ Malt ~/.julia/packages/Malt/yA40d/src/Malt.jl:137
        [6] Worker
          @ ~/.julia/packages/Malt/yA40d/src/Malt.jl:114 [inlined]

[pankgeorg]

I'm a bit concerned that all our tests are red. The ones on pre and nightly are red -I think- mostly because there have been significant changes to cancelling tasks (we kind of use undocumented functions, oops). Could you help us look into the others? Beyond this PR of course!

[giordano]

Yes, but they're failing already in main (and already before my previous PR 😅)

Could you help us look into the others?

To be helpful, I'd need to understand the motivation behind the tests. For example I don't know what

Malt.jl/test/starting.jl

Line 11 in 017aaf3

@test tend - tstart < 15.0

really wants to test.

In meantime a new version including this PR would be very welcome downstream 😃

[giordano]

To be helpful, I'd need to understand the motivation behind the tests. For example I don't know what

Malt.jl/test/starting.jl

Line 11 in 017aaf3

@test tend - tstart < 15.0

really wants to test.

I decided to give it a go because of lack of sleep, so I went down a rabbit hole trying to decipher what the test was really trying to assert, and the result of my investigation is #105. This doesn't solve the problems with Julia nightly, but at least there should be fewer red marks on CI.

[pankgeorg]

I decided to give it a go because of lack of sleep,

I really appreciate and hope the decision did not cause more lack of sleep!

[giordano]

@pankgeorg could you please register v1.4.1? Thanks!

[pankgeorg]

@pankgeorg could you please register v1.4.1? Thanks!

JuliaRegistries/General#151450 !!!