Packages seem to use non-parallel precompilation when automatically added from using statement in REPL

[KristofferC]

julia> using OhMyREPL
 │ Package OhMyREPL not found, but a package named OhMyREPL is available from a
 │ registry. 
 │ Install package?
 │   (JuliaCon2025) pkg> add OhMyREPL 
 └ Select environment:
   1: `~/Documents/JuliaCon2025/Project.toml` (@)
 > 2: `~/.julia/environments/v1.12/Project.toml` (@v#.#)
   Resolving package versions...
   Installed OhMyREPL ─ v0.5.31
    Updating `~/.julia/environments/v1.12/Project.toml`
  [5fb14364] + OhMyREPL v0.5.31
    Updating `~/.julia/environments/v1.12/Manifest.toml`
  [5fb14364] + OhMyREPL v0.5.31
  [44cfe95a] ↑ Pkg v1.12.0 ⇒ v1.13.0
  [458c3c95] ↑ OpenSSL_jll v3.5.0+0 ⇒ v3.5.1+0
  [8e850b90] ↑ libblastrampoline_jll v5.12.0+0 ⇒ v5.13.1+0
[ Info: Precompiling OhMyREPL [5fb14364-9ced-5910-84b2-373655c76a03] 

The last line is outputted when non-parallel precompilation is done. I feel it should have used the parallel one.

[IanButterworth]

Try with JULIA_DEBUG=precompilation? Debug logs may need some tweaking to be helpful.

[KristofferC]

A scenario where this happens:

• Activate a temp project
• Do using OhMyREPL and tell it to install into the default env
• Even though we install into the default env (which is not active), at

  julia/base/loading.jl

  Lines 2627 to 2633 in 59a7bb3

  	project = active_project()
  	if !generating_output() && !parallel_precompile_attempted && !disable_parallel_precompile && @isdefined(Precompilation) && project !== nothing &&
  	isfile(project) && project_file_manifest_path(project) !== nothing
  	parallel_precompile_attempted = true
  	unlock(require_lock)
  	try
  	Precompilation.precompilepkgs([pkg.name]; _from_loading=true, ignore_loaded=false)

  
  we look at the active project and since this is a new temp project isfile(project) is false and we do not parallel compile.

But maybe we shouldn't parallel precopile in cases like this where we load from a different env than the package was installed in.