LOAD_PATH in Pkg3 about pkg.jl HOT 6 CLOSED

Interaction with checked out packages

At first I thought that checked out packages were related to this, but that's actually a mostly independent matter. When you check out a package, it gets checked out in JULIA_DEVDIR which defaults to joinpath(DEPOTS[1], "dev") and a path to it is placed in the current environment's manifest. However, when the current environment is an old-style implicit one, there is no Manifest.toml file to put a path into, so what does one do? I can see two options:

1. Check out the package into the implicit environment directory structure instead of in JULIA_DEVDIR.

2. Check out the package into JULIA_DEVDIR as normal, but create a symlink from that location into the implicit environment directory.

I'm not sure which approach is better.

There's also the question of "What is the current environment?" I would say that the current environment should be the environment corresponding to the first entry in LOAD_PATH that exists.

from pkg.jl.

Some questions:

• Should LOAD_PATH be renamed? E.g. to ENV_PATH or ENVIRONMENTS?
• Or should the command-line options --env= and --env+ be --load-path= and --load-path+?

from pkg.jl.

Example usage, you might be working on a project and want to use a profiler and debugger, and so start julia using julia --env+NamedEnv("devtools") which would have the effect of appending the devtools named environment to your LOAD_PATH, thereby giving you access to any of the packages installed in there, in addition to what's in your current project's environment.

This does kind of suggest that the NamedEnv("devtools") syntax is too verbose, so maybe we should have more concise syntaxes. Maybe --env+@devtools? And @@ for CurrentProject()? And !@devtools to create the devtools named environment if it doesn't already exist? Or maybe we don't need a syntax for that. The long syntax is fine for setting LOAD_PATH since that tends to be done once in a config file somewhere, but the command-line really wants concise syntax.

from pkg.jl.

1. Would LOAD_PATH then effectively implement what is described as DEPOT_PATH in the Julep?

2. If I have projects scattered all over my home directory (eg because I keep them alongside LaTeX source and other misc stuff from coauthors relevant to a working paper, organized into directories, which may not follow the Julia package layout from their root), would it be sufficient to just make a single directory, put it in LOAD_PATH, and symlink in the project directories there?

from pkg.jl.

In short, no. The best description of the roles of LOAD_PATH and DEPOT_PATH in Pkg3 are now here: JuliaLang/julia#25709. This will obviously be properly documented before we release 1.0 final... we're still working on integration. In short, LOAD_PATH is used to determine what packages to load while DEPOT_PATH is used, among other things, to find installed versions of packages based on their UUID and SHA-1 git hash (also to look for registries and named environments).

from pkg.jl.

This is now implemented as of JuliaLang/julia#25455.

from pkg.jl.