swprintf ccall test failure on CI

[vtjnash]

https://build.julialang.org/#/builders/33/builds/3983

Error in testset ccall:
Error During Test at /usr/home/julia/buildbot/worker-tabularasa/tester_freebsd64/build/share/julia/test/ccall.jl:1713
  Got exception outside of a @test
  InexactError: check_top_bit(UInt64, -1)
  Stacktrace:
    [1] throw_inexacterror(f::Symbol, #unused#::Type{UInt64}, val::Int32)
      @ Core ./boot.jl:602
    [2] check_top_bit
      @ ./boot.jl:616 [inlined]
    [3] toUInt64
      @ ./boot.jl:726 [inlined]
    [4] UInt64
      @ ./boot.jl:757 [inlined]
    [5] convert
      @ ./number.jl:7 [inlined]
    [6] cconvert
      @ ./essentials.jl:396 [inlined]
    [7] #unsafe_wrap#78
      @ ./pointer.jl:89 [inlined]
    [8] unsafe_string
      @ ./c.jl:418 [inlined]
    [9] macro expansion
      @ /usr~/buildbot/worker-tabularasa/tester_freebsd64/build/share/julia/test/ccall.jl:1722 [inlined]
   [10] macro expansion
      @ /usr~/buildbot/worker/package_freebsd64/build/usr/share/julia/stdlib/v1.6/Test/src/Test.jl:1113 [inlined]
   [11] top-level scope
      @ /usr~/buildbot/worker-tabularasa/tester_freebsd64/build/share/julia/test/ccall.jl:1714
   [12] include(mod::Module, _path::String)
      @ Base ./Base.jl:379
   [13] include
      @ /usr~/buildbot/worker-tabularasa/tester_freebsd64/build/share/julia/test/testdefs.jl:13 [inlined]
   [14] macro expansion
      @ /usr~/buildbot/worker-tabularasa/tester_freebsd64/build/share/julia/test/testdefs.jl:25 [inlined]
   [15] macro expansion
      @ /usr~/buildbot/worker/package_freebsd64/build/usr/share/julia/stdlib/v1.6/Test/src/Test.jl:1113 [inlined]
   [16] macro expansion
      @ /usr~/buildbot/worker-tabularasa/tester_freebsd64/build/share/julia/test/testdefs.jl:24 [inlined]
   [17] macro expansion
      @ ./timing.jl:310 [inlined]
   [18] top-level scope
      @ /usr~/buildbot/worker-tabularasa/tester_freebsd64/build/share/julia/test/testdefs.jl:22
   [19] eval
      @ ./boot.jl:360 [inlined]
   [20] runtests(name::String, path::String, isolate::Bool; seed::UInt128)
      @ Main /usr~/buildbot/worker-tabularasa/tester_freebsd64/build/share/julia/test/testdefs.jl:28
   [21] (::Distributed.var"#106#108"{Distributed.CallMsg{:call_fetch}})()
      @ Distributed /usr~/buildbot/worker/package_freebsd64/build/usr/share/julia/stdlib/v1.6/Distributed/src/process_messages.jl:294
   [22] run_work_thunk(thunk::Distributed.var"#106#108"{Distributed.CallMsg{:call_fetch}}, print_error::Bool)
      @ Distributed /usr~/buildbot/worker/package_freebsd64/build/usr/share/julia/stdlib/v1.6/Distributed/src/process_messages.jl:79
   [23] macro expansion
      @ /usr~/buildbot/worker/package_freebsd64/build/usr/share/julia/stdlib/v1.6/Distributed/src/process_messages.jl:294 [inlined]
   [24] (::Distributed.var"#105#107"{Distributed.CallMsg{:call_fetch}, Distributed.MsgHeader, Sockets.TCPSocket})()
      @ Distributed ./task.jl:392

julia/test/ccall.jl

Line 1720 in 758fde9

len = @ccall swprintf(buffer::Ptr{Cwchar_t}, n::Csize_t, "α+%ls=%hhd"::Cwstring; "β"::Cwstring, 0xf::UInt8)::Cint

[musm]

I don't think swprintf takes a length argument n::Csize_t, this would explain why swprintf_s is used on Windows (explaining the segfault

julia/test/ccall.jl

Line 1718 in 758fde9

len = @ccall swprintf_s(buffer::Ptr{Cwchar_t}, n::Csize_t, "α+%ls=%hhd"::Cwstring; "β"::Cwstring, 0xf::UInt8)::Cint

)
Edit: I think that only applies in the Windows case, and is irrelevant in this case.

[StefanKarpinski]

I've been trying to use the ci label for all issues that affect CI reliability, but it seems like no one else is using it. Can we agree on a label that will give us a list of all ongoing CI problems?

[simonbyrne]

Something does appear to be wrong with sprintf/swprintf on Windows: #36040 (comment)

[vtjnash]

This issue has nothing to do with windows, sprintf, or %f but is only a bug on FreeBSD in their implementation of %ls