Could the package compiler check for relocatabiliy?

[ValentinKaisermayer]

For now this is a per package responsibility. It can be very easily overlooked and a potential user has no idea.

Is it possible to analyze the system image and tell if there are any paths pointing to the build machine?

[fatteneder]

Copy of my message from slack:

FWIW: Conda does a simple find-and-replace in text and binary files to relocate baked-in paths: https://prefix.dev/blog/what-is-a-conda-package#the-placeholder-trick. I guess that's too primitive and costly for us, as we have full control over the compilation process, whereas conda wants to serve pkgs for different stacks.

I guess the difficulty with that approach is patching the correct path when deploying/running the image. Isn't a PackageCompiler image meant to just be copied and pasted between machines and you then start julia with a --sysimage? So the patching would need to be done on every start and would require changes in julia itself.

Not sure if the following also applies to sysimages.
But at least for the native pkgimages in julia you have to keep the .ji and .so files in sync, e.g. you have to replace strings in both files. But once you do that in the .ji file, you change its content hash. So you will then also have to update in the .so again to avoid recompilation.

[fatteneder]

But if its only about checking that its relocatable, then the find-replace strategy might be good enough.

[ValentinKaisermayer]

I think this is not about fixing it but letting the users know that there is an issue. Potentially the user will create an issue in the problematic Julia package, or even better make a pull request.

A first step could be to just search the sysimage for paths to the host machine's .julia folder and spit them out. Similar to this.

[ValentinKaisermayer]

For instance Oxygen.jl is not full relocatable because of some js bundle. OxygenFramework/Oxygen.jl#259

And even if you are using RelocatableFolders.jl there might be mistakes: MakieOrg/Makie.jl#4410

[ValentinKaisermayer]

There is Base.isrelocatable(pkg)

https://github.com/JuliaLang/julia/blob/fc1fb4139e71ee57e90263769a8fef510353f11c/base/loading.jl#L1911