Allow for specifying shared named environments on Julia start

[oschulz]

To my knowledge, it's currently not possible to specify shared named environments via JULIA_PROJECT or julia --project=... without using the full path.

It would be very useful to have an equivalent to ] activate --shared ... - both for convenience, but also because the full path may be system-dependent, making things complicated in a heterogeneous environment, esp. when access to remote systems is involved.

See also https://discourse.julialang.org/t/activating-a-shared-named-environment-via-julia-project/36975 .

[davidanthoff]

It would be awesome if the @ that already works in the REPL for shared env worked for --project and JULIA_PROJECT as well.

[fredrikekre]

diff --git a/base/initdefs.jl b/base/initdefs.jl
index 85a3d57..f90f5c5 100644
--- a/base/initdefs.jl
+++ b/base/initdefs.jl
@@ -217,7 +217,9 @@ function init_load_path()
     HOME_PROJECT[] =
         project === nothing ? nothing :
         project == "" ? nothing :
-        project == "@." ? current_project() : abspath(expanduser(project))
+        project == "@." ? current_project() :
+        startswith(project, '@') ? find_env_in_depot(project[2:end]) :
+        abspath(expanduser(project))
     append!(empty!(LOAD_PATH), paths)
 end
 
@@ -235,17 +237,7 @@ function load_path_expand(env::AbstractString)::Union{String, Nothing}
         env = replace(env, '#' => VERSION.minor, count=1)
         env = replace(env, '#' => VERSION.patch, count=1)
         name = env[2:end]
-        # look for named env in each depot
-        for depot in DEPOT_PATH
-            path = joinpath(depot, "environments", name)
-            isdir(path) || continue
-            for proj in project_names
-                file = abspath(path, proj)
-                isfile_casesensitive(file) && return file
-            end
-        end
-        isempty(DEPOT_PATH) && return nothing
-        return abspath(DEPOT_PATH[1], "environments", name, project_names[end])
+        return find_env_in_depot(name)
     end
     # otherwise, it's a path
     path = abspath(env)
@@ -261,6 +253,20 @@ function load_path_expand(env::AbstractString)::Union{String, Nothing}
 end
 load_path_expand(::Nothing) = nothing
 
+# looks for named env in each depot
+function find_env_in_depot(name::String)
+    for depot in DEPOT_PATH
+        path = joinpath(depot, "environments", name)
+        isdir(path) || continue
+        for proj in project_names
+            file = abspath(path, proj)
+            isfile_casesensitive(file) && return file
+        end
+    end
+    isempty(DEPOT_PATH) && return nothing
+    return abspath(DEPOT_PATH[1], "environments", name, project_names[end])
+end
+
 function active_project(search_load_path::Bool=true)
     for project in (ACTIVE_PROJECT[], HOME_PROJECT[])
         project == "@" && continue

Will break people that have directories with @ though.

[oschulz]

Thanks, @fredrikekre !

[davidanthoff]

Will break people that have directories with @ though.

In the same way that it breaks them in the REPL case, right? And they can always use ./@myfolder, right? While this might break some folks, I think it is actually more important that the REPL and command line and env var story is in sync, i.e. @foo always does the same thing.

[oschulz]

I guess we can assume few (or no) people will use directory names starting with "@" :-)

[StefanKarpinski]

Yes, it would be good if we supported this consistently.

[oschulz]

Would @fredrikekre 's solution be acceptable?

[oschulz]

@fredrikekre , are you planning to make a PR? If you have your hands full, I can do it, but I don't want to claim credit for your solution.

[fredrikekre]

Go ahead. You can put me as co-author if you think it matters.

[oschulz]

Ok, I'll see that I get this in for v1.6.

[oschulz]

Sorry, kinda missed that v1.6 window (by a lot), due to overload ...

[oschulz]

Sorry this took so long, for such a tiny thing: #40025