Wrong "Invalid redefinition of type" for certain UnionAll field types

[stev47]

Minimal example:

using Revise

mktemp() do f, io
    write(io, """
        struct A{T} end
        struct B{T, S}
          a::A{<:T}
        end
        """)
    close(io)
    includet(f)
end

results in

ERROR: LoadError: invalid redefinition of type B

The above works (try in fresh session) if either:

• A{<:T} is replaced with A{T},
• S is removed, or
• includet replaced by standard include

This breaks normal Revise workflow even if no types are changed at all.
#734 possibly related.

[aviatesk]

The above example seems to work on the latest master and v1.10-beta3 with Revise v3.5.7. What is your Julia version and Revise version?

[stev47]

The above example seems to work on the latest master and v1.10-beta3 with Revise v3.5.7. What is your Julia version and Revise version?

julia> versioninfo()
Julia Version 1.9.3
Commit bed2cd540a1 (2023-08-24 14:43 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 16 × AMD Ryzen 7 5825U with Radeon Graphics
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-14.0.6 (ORCJIT, znver3)
  Threads: 1 on 16 virtual cores
Environment:
  JULIA_PKG_USE_CLI_GIT = 1

(@v1.9) pkg> status Revise
Status `~/.julia/environments/v1.9/Project.toml`
  [295af30f] Revise v3.5.7

I did not try yet on v1.10 or master

[stev47]

The above example seems to work on the latest master and v1.10-beta3 with Revise v3.5.7. What is your Julia version and Revise version?

I managed to reproduce both on Julia 1.10.0-beta3 and current master (1.11.0-DEV.745), each with Revise v3.5.7.

[thofma]

Might be a dup of #753?

[timholy]

Thanks for the MWE!

Bad news: this may be a Julia bug. (Revise just exploits the standard Julia functionality here.) includet effectively re-evaluates the file, skipping over anything that it think it can omit. You can mimic this by calling include twice on the same file:

# don't load Revise
julia> mktemp() do f, io
           write(io, """
               struct A{T} end
               struct B{T, S}
                 a::A{<:T}
               end
               """)
           close(io)
           include(f)
           include(f)
       end
ERROR: LoadError: invalid redefinition of type B
Stacktrace:
 [1] top-level scope
   @ /tmp/jl_KJFFPN:2
 [2] include
   @ ./client.jl:489 [inlined]
 [3] (::var"#1#2")(f::String, io::IOStream)
   @ Main ./REPL[1]:10
 [4] mktemp(fn::var"#1#2", parent::String)
   @ Base.Filesystem ./file.jl:738
 [5] mktemp(fn::Function)
   @ Base.Filesystem ./file.jl:736
 [6] top-level scope
   @ REPL[1]:1
in expression starting at /tmp/jl_KJFFPN:2

but changing a::A{<:T} to just a::A{T} does not trigger that error.