Precompilation workload: set "JULIA_PKG_UNPACK_REGISTRY" => nothing

[DilumAluthge]

Fixes #3663

[KristofferC]

How does JULIA_PKG_UNPACK_REGISTRY have anything to do with a modified DEPOT_PATH?

[DilumAluthge]

If you don't modify the depot path, there's no need to precompile Pkg (because you can use the existing cache files), so the precompilation workload never gets run.

If you do modify the depot path, Pkg needs to be precompiled, so the precompilation workload gets run. If the "unpack registries" environment variable is set, this clashes with the "setup" function inside the precompilation workflow, which specifically sets up a non-unpacked registry.

[KristofferC]

To me, it seems like we should just set some kind of default DEPOT_PATH when running the precompile workload? Otherwise, you won't precompile the whole unpack part, no?

[DilumAluthge]

To me, it seems like we should just set some kind of default DEPOT_PATH when running the precompile workload

I think we already do that:

Pkg.jl/src/precompile.jl

Lines 10 to 11 in ee39026

	empty!(DEPOT_PATH)
	pushfirst!(DEPOT_PATH, tmp)

[DilumAluthge]

Otherwise, you won't precompile the whole unpack part, no?

Which code path are you talking about precompiling? The default code path (the user doesn't set the JULIA_PKG_UNPACK_REGISTRY environment variable), or the code path I'm hitting (the user has set the JULIA_PKG_UNPACK_REGISTRY environment variable to true)?