store the path to where a package got loaded

[KristofferC]

And use it in pkgdir

Fixes #33210

[timholy]

So cool! Is #35663 next?

[KristofferC]

What behavior do you want there? A warning when the package would have gotten loaded from a different place than if it was not already loaded?

[timholy]

Personally, I want an error---don't let the user change environments.

[KristofferC]

Storing the path here is an improvement but it isn't really perfect. For example, if I make a sysimage, send it to a friend and they uses it, loads the same version of a package that is in the sysimage, that will have a different computed path where that package would be loaded from, but it is still the same package version. What we should store is probably more akin to "how this package got loaded". And there are a few ways a package can get loaded:

• by git-tree-sha1
• by explicit path
• by implicit path due to the folder being in LOAD_PATH (how stdlibs are loaded).

In the case above, the same git-tree-sha1 would be used so even if the absolute paths are resolved differently, it is still not a problem.

[timholy]

Seems like this must have missed a case:

julia> using JuliaInterpreter

julia> pathof(JuliaInterpreter)
"/home/tim/.julia/packages/JuliaInterpreter/muncv/src/JuliaInterpreter.jl"

julia> exit()
tim@diva:~/.julia/dev/Revise$ julia-master --startup-file=no -q
julia> using Revise

julia> using JuliaInterpreter

julia> pathof(JuliaInterpreter)

julia>

[KristofferC]

Thanks, will look at it.