fatal: error thrown (TypeError from typeassert) & subsequent crash on yield(current_task())

[Seelengrab]

I'd have expected either a noop, or a ConcurrencyViolationError here.

Full stacktrace/MWE:

[sukera@tower ~]$ jl1101  -q
julia> versioninfo()
Julia Version 1.10.1
Commit 7790d6f0641 (2024-02-13 20:41 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 24 × AMD Ryzen 9 7900X 12-Core Processor
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-15.0.7 (ORCJIT, znver3)
Threads: 1 default, 0 interactive, 1 GC (on 24 virtual cores)
Environment:
  JULIA_PKG_USE_CLI_GIT = true

julia> yield(current_task())
ERROR: fatal: error thrown and no exception handler available.
TypeError(func=:typeassert, context="", expected=Int32, got=nothing)
ijl_type_error_rt at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/rtutils.c:119
ijl_type_error at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/rtutils.c:127
uv_write at ./stream.jl:1048
unsafe_write at ./stream.jl:1120
write at ./strings/io.jl:248 [inlined]
print at ./strings/io.jl:250 [inlined]
#with_output_color#994 at ./util.jl:112
with_output_color at ./util.jl:73 [inlined]
#printstyled#995 at ./util.jl:141 [inlined]
printstyled at ./util.jl:141
unknown function (ip: 0x71ad2433d070)
_jl_invoke at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/gf.c:3076
display_error at ./client.jl:110
unknown function (ip: 0x71ad2433cfc9)
_jl_invoke at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/gf.c:3076
display_error at ./client.jl:114
jfptr_display_error_82458.1 at /home/sukera/Downloads/jl/julia-1.10.1/lib/julia/sys.so (unknown line)
_jl_invoke at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/gf.c:3076
jl_apply at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/julia.h:1982 [inlined]
jl_f__call_latest at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/builtins.c:812
#invokelatest#2 at ./essentials.jl:892 [inlined]
invokelatest at ./essentials.jl:889 [inlined]
_start at ./client.jl:554
jfptr__start_82662.1 at /home/sukera/Downloads/jl/julia-1.10.1/lib/julia/sys.so (unknown line)
_jl_invoke at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/gf.c:2894 [inlined]
ijl_apply_generic at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/gf.c:3076
jl_apply at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/julia.h:1982 [inlined]
true_main at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/jlapi.c:582
jl_repl_entrypoint at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/src/jlapi.c:731
main at /cache/build/default-maughin-0/julialang/julia-release-1-dot-10/cli/loader_exe.c:58
unknown function (ip: 0x71ad2551bccf)
__libc_start_main at /usr/lib/libc.so.6 (unknown line)
unknown function (ip: 0x4010b8)

[vtjnash]

We should perhaps make the warning against this more scary looking? Throwing a ConcurrencyViolationError in some of the easier cases (such as this) may be possible too.

!!! warning
    It is incorrect to use `schedule` on an arbitrary `Task` that has already been started.
    See [the API reference](@ref low-level-schedule-wait) for more information.

[Seelengrab]

I was mostly just curious what happened, since wait catches this trivial failure case, so my thinking was that yield should too. I'll see if I get to a PR later today.