Why can I import a package not in my environment?

Tooling Package Management
,
1

In an ongoing effort to be a bit cleaner in my environments and cleaning up my default env, I encountered a situation I do not understand: even though Plots isn’t added to the current environment, I can still import it.

(test_sysdynutils) pkg> st --manifest
Status `~/[...]/test_sysdynutils/Manifest.toml`
  [6ea1bd40] SysDynUtils v1.0.0-DEV `~/.julia/dev/SysDynUtils`
  [628e9319] TaylorInterface v0.1.1
  [8f399da3] Libdl
  [9a3f8284] Random
  [ea8e919c] SHA v0.7.0

julia> using Plots

(test_sysdynutils) pkg> activate
  Activating project at `~/.julia/environments/v1.10`

(@v1.10) pkg> remove Plots
    Updating `~/.julia/environments/v1.10/Project.toml`
  [91a5bcdd] - Plots v1.40.8
    Updating `~/.julia/environments/v1.10/Manifest.toml`
[Bunch of stuff removed]

julia> using Plots
 │ Package Plots not found, but a package named Plots is available from a registry. 
 │ Install package?
 │   (test_sysdynutils) pkg> add Plots 
 └ (y/n/o) [y]: n

How come? Is the default environment added to every other environment (I’d reckon that would be really bad for reproducibility)?

2

Yes, the default environment is accessible from every other environment, see this thread for more details:

The best practice is therefore to have basically nothing in the default environment, except pure development tools (Revise.jl, Cthulhu.jl, JET.jl, BenchmarkTools.jl, etc.)

3

Makes sense, thanks!