Loading main package from higher-level env fails with extension of package in current env

[oschulz]

We currently run into this problem with Plots plus IJulia frequently (on Julia v1.9.0):

using Plots

[ Info: Precompiling IJuliaExt [2f4121a4-3b3a-5ce6-9c5e-1f2673ce168a]
ERROR: LoadError: ArgumentError: Package IJulia [7073ff75-c697-5162-941a-fcdaad2a7d2a] is required but does not seem to be installed:
 - Run `Pkg.instantiate()` to install all recorded dependencies.

IJulia is a bit peculiar in that you can really only have one version of it at the same time, otherwise these "IJulia version doesn't match ..." warnings appear. This is because the (default) Jupyter kernelspec is bound to a specific IJulia version (since "kernel.json" points to ".julia/packages/IJulia/SOME_VERSION/src/kernel.jl"). So one often keeps IJulia in the default (e.g. "v1.9") environment and out of specific project environment like the the "Project/Manifest.toml" kept next to a notebook. Plots, on the other hand, will typically be part of the "local" environment, of course.

For details, see JuliaPlots/Plots.jl#4719.

We initially thought this would be fixed by #48352, but the issue seems to persists in Julia v1.9.0 (we'll use a workaround based on Base.require, provided by @KristofferC (thanks!), in Plots.jl for now).

CC @t-bltg

[Liozou]

Duplicate of #49656, this was fixed by #49701. I tried locally and I could reproduce the problem on julia v1.9.0 but not v1.9.1 and later, so I'm marking this as fixed.