fails in Julia 1.8 with step_expr!(::Any, ::Any, ::Any, ::Bool) is ambiguous

[tpapp]

  MethodError: step_expr!(::Any, ::Any, ::Any, ::Bool) is ambiguous. Candidates:
    step_expr!(interp::JET.ConcreteInterpreter, frame::JuliaInterpreter.Frame, node, istoplevel::Bool) in JET at /home/tamas/.julia/packages/JET/ymRji/src/toplevel/virtualprocess.jl:1167
    step_expr!(recurse, frame::JuliaInterpreter.Frame, node, istoplevel::Bool) in JuliaInterpreter at /home/tamas/.julia/packages/JuliaInterpreter/cxlKp/src/interpret.jl:457
  To resolve the ambiguity, try making one of the methods more specific, or adding a new method more specific than any of the existing applicable methods.
  Stacktrace:          
    [1] step_expr!(interp::JET.ConcreteInterpreter{JET.var"#usemodule_with_err_handling#54"{JET.VirtualProcessResult, String, Nothing, Set{Symbol}, Base.RefValue{LineNumberNode}, JET.var"#err
_handler#47"{JET.VirtualProcessResult, String, Base.RefValue{LineNumberNode}}}, JETAnalyzer{JET.BasicPass{typeof(JET.jetanalyzer_function_filter)}}, Expr}, frame::JuliaInterpreter.Frame, node
::Any, istoplevel::Bool)       
      @ JET ~/.julia/packages/JET/ymRji/src/toplevel/virtualprocess.jl:1177
    [2] step_expr!(recurse::Any, frame::JuliaInterpreter.Frame, istoplevel::Bool)
      @ JuliaInterpreter ~/.julia/packages/JuliaInterpreter/cxlKp/src/interpret.jl:614
    [3] selective_eval!(recurse::Any, frame::JuliaInterpreter.Frame, isrequired::Vector{Bool}, istoplevel::Bool)
      @ LoweredCodeUtils ~/.julia/packages/LoweredCodeUtils/nrimZ/src/codeedges.jl:844
    [4] selective_eval_fromstart!
      @ ~/.julia/packages/LoweredCodeUtils/nrimZ/src/codeedges.jl:870 [inlined]
    [5] partially_interpret!(interp::JET.ConcreteInterpreter{JET.var"#usemodule_with_err_handling#54"{JET.VirtualProcessResult, String, Nothing, Set{Symbol}, Base.RefValue{LineNumberNode}, JE
T.var"#err_handler#47"{JET.VirtualProcessResult, String, Base.RefValue{LineNumberNode}}}, JETAnalyzer{JET.BasicPass{typeof(JET.jetanalyzer_function_filter)}}, Expr}, mod::Module, src::Core.Co
deInfo)
      @ JET ~/.julia/packages/JET/ymRji/src/toplevel/virtualprocess.jl:1020

Version:

(jl_hnFB0L) pkg> st
Status `/tmp/jl_hnFB0L/Project.toml`
⌅ [c3a54625] JET v0.7.14

I know that Julia 1.8 is rather old, and so is the JET.jl version above, but I am using JET in CI where I test for that version (the minimum supported).

Is there a recommended workaround?

[Jamie-Hilditch]

I think this issue was introduced in the latest version of JuliaInterpreter (v0.9.36). The signature of JuliaInterpreter.step_expr! was changed in this PR JuliaDebug/JuliaInterpreter.jl#645. In a very non-rigorous test, forcing JET to use JuliaInterpreter v0.9.35 did not trigger this issue.

[aviatesk]

This issue has been fixed in the latest version of JET, but unfortunately, the latest JET doesn't support Julia 1.8 (its minimum supported version is currently 1.10.0). I apologize for the inconvenience, but if you're using JET with 1.8, please cap the version of JuliaInterpreter.

[Jamie-Hilditch]

This is rather annoying little issue. As far as I'm aware Julia has no mechanism for restricting dependencies of dependencies. However, like @tpapp I'm only really using Julia 1.8 for CI and so my workaround is to include a job step in my CI workflow that adds JuliaInterpreter v0.9.35 as a test dependency whenever using Julia 1.8. e.g.

- id: hack-for-julia18
  if: matrix.version == '1.8'
  run: julia --project=test -e 'using Pkg; Pkg.add(name="JuliaInterpreter", version="0.9.35"); Pkg.compat("JuliaInterpreter", "< 0.9.36")'

This, at least for now, appears to resolve the issue.

[aviatesk]

I’m sorry for forcing such a workaround, but we still don’t have any plans to reinstate support for versions prior to v1.10, so I’ll go ahead and close the issue.