add Base.isprecompiled(pkg::PkgId)

[IanButterworth]

This is based on the Pkg internal _is_stale but inverted, with caching optional via kwargs so that Pkg can instead use this and remain efficient.

It's more generally useful, and good to keep in-line with Base functionality.

julia> @time Base.isprecompiled(Base.PkgId(Revise))
  0.006545 seconds (7.82 k allocations: 392.570 KiB)
true

julia> @time Base.isprecompiled(Base.PkgId(Revise))
  0.005438 seconds (7.82 k allocations: 392.570 KiB)
true

shell> rm -rf ~/.julia/compiled/v1.10/Revise

julia> @time Base.isprecompiled(Base.PkgId(Revise))
  0.000313 seconds (275 allocations: 17.773 KiB)
false

julia> @time Base.isprecompiled(Base.PkgId(Revise))
  0.000287 seconds (275 allocations: 17.773 KiB)
false

[IanButterworth]

Bump @KristofferC

[KristofferC]

I would have thought this function would also be used by loading to check if a precompile file is stale before trying to precompile it. Is there a reason that couldn't be done? Perhaps it needs to return a bit more than just true/false then?

[IanButterworth]

I gave that a go twice and failed twice because the staledeps caching and conversion from Any is quite different in the Pkg and Base usage patterns. You may have a clearer vision on the loading system to come up with a simple approach.

At least, it will need to be broken up into an internal function that can be used inside the loading loop, I think.

This is blocking making Pkg.precompile use the pidlocks. Perhaps that could be a follow on PR?

[vtjnash]

being simultaneously mutating (rather than a pure check) seems out-of-character for this function

Suggested change

	try
	# update timestamp of precompilation file so that it is the first to be tried by code loading
	touch(path_to_try)
	catch ex
	# file might be read-only and then we fail to update timestamp, which is fine
	ex isa IOError || rethrow()
	end

[IanButterworth]

IMO it seems like a reasonable thing to do for systemic efficiency