Base.require leads to ERROR: LoadError: UndefVarError: UUID not defined in Main

[mortenpi]

This popped up in DataSets.jl nightly tests, and appears to be some weird regression in Base.require. The tarball (mwe.tar.gz) has the MWE environment (which basically consists of a trivial empty package):

$ julia +nightly --project

julia> using UUIDs: UUID

julia> Base.require(Base.PkgId(UUID("89b7a33a-382e-4698-a931-421b088d35a2"), "DummyStorageBackends"))
┌ Info: Precompiling DummyStorageBackends [89b7a33a-382e-4698-a931-421b088d35a2]
└ @ Base loading.jl:2647
ERROR: LoadError: UndefVarError: `UUID` not defined in `Main`
Stacktrace:
 [1] top-level scope
   @ stdin:2
in expression starting at stdin:2
ERROR: Failed to precompile DummyStorageBackends [89b7a33a-382e-4698-a931-421b088d35a2] to "/home/mortenpi/.julia/compiled/v1.12/DummyStorageBackends/jl_TtujDq".
Stacktrace:
  [1] error(s::String)
    @ Base ./error.jl:35
  [2] compilecache(pkg::Base.PkgId, path::String, internal_stderr::IO, internal_stdout::IO, keep_loaded_modules::Bool; flags::Cmd, reasons::Dict{…})
    @ Base ./loading.jl:2762
  [3] (::Base.var"#1069#1070"{Base.PkgId})()
    @ Base ./loading.jl:2204
  [4] mkpidlock(f::Base.var"#1069#1070"{Base.PkgId}, at::String, pid::Int32; kwopts::@Kwargs{stale_age::Int64, wait::Bool})
    @ FileWatching.Pidfile ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/FileWatching/src/pidfile.jl:95
  [5] #mkpidlock#6
    @ ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/FileWatching/src/pidfile.jl:90 [inlined]
  [6] trymkpidlock(::Function, ::Vararg{Any}; kwargs::@Kwargs{stale_age::Int64})
    @ FileWatching.Pidfile ~/.julia/juliaup/julia-nightly/share/julia/stdlib/v1.12/FileWatching/src/pidfile.jl:116
  [7] #invokelatest#2
    @ ./essentials.jl:1032 [inlined]
  [8] invokelatest
    @ ./essentials.jl:1027 [inlined]
  [9] maybe_cachefile_lock(f::Base.var"#1069#1070"{Base.PkgId}, pkg::Base.PkgId, srcpath::String; stale_age::Int64)
    @ Base ./loading.jl:3348
 [10] maybe_cachefile_lock
    @ ./loading.jl:3345 [inlined]
 [11] _require(pkg::Base.PkgId, env::Nothing)
    @ Base ./loading.jl:2200
 [12] __require_prelocked(uuidkey::Base.PkgId, env::Nothing)
    @ Base ./loading.jl:2033
 [13] #invoke_in_world#3
    @ ./essentials.jl:1064 [inlined]
 [14] invoke_in_world
    @ ./essentials.jl:1061 [inlined]
 [15] _require_prelocked
    @ ./loading.jl:2024 [inlined]
 [16] _require_prelocked
    @ ./loading.jl:2023 [inlined]
 [17] macro expansion
    @ ./lock.jl:273 [inlined]
 [18] require(uuidkey::Base.PkgId)
    @ Base ./loading.jl:2018
 [19] top-level scope
    @ REPL[2]:1
Some type information was truncated. Use `show(err)` to see complete types.

Works file on 1.10 and earlier. Looking at the PkgEval results for DataSets.jl, it looks like it started failing about 1-2 weeks ago. I'll see if I can bisect it to a commit.

julia> versioninfo()
Julia Version 1.12.0-DEV.15
Commit 1c25d93ca8a (2024-02-19 01:35 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: 16 × 12th Gen Intel(R) Core(TM) i7-1260P
  WORD_SIZE: 64
  LLVM: libLLVM-16.0.6 (ORCJIT, alderlake)
Threads: 1 default, 0 interactive, 1 GC (on 16 virtual cores)

[mortenpi]

Bisect blames #53111

[KristofferC]

The reason is the following:

julia> pkgid = Base.PkgId(Base.UUID("89b7a33a-382e-4698-a931-421b088d35a2"), "DummyStorageBackends");

julia> show(pkgid)
Base.PkgId(Base.UUID("89b7a33a-382e-4698-a931-421b088d35a2"), "DummyStorageBackends")

julia> using UUIDs: UUID

# `Base` prefix is gone for `UUID`:
julia> show(pkgid)
Base.PkgId(UUID("89b7a33a-382e-4698-a931-421b088d35a2"), "DummyStorageBackends")

This makes

julia/base/loading.jl

Line 2562 in 59102aa

Base.track_nested_precomp($(vcat(Base.precompilation_stack, pkg)))

not print the required Base prefix for the code which will be executed in Main in another process. cc @IanButterworth

[KristofferC]

This is pretty much the exact bug as #42329 :) (which also makes this a great example of #29466)