`Plots` precompilation broken on future `1.10`

[t-bltg]

Example of failing CI on 1.10-beta2.

CI passes on 1.6 -> 1.9.

Looks like #50541 ?

cc @BeastyBlacksmith.

[vtjnash]

Looks like several package bugs similar to this

Failed to precompile InspectDR [d0351b0e-4b05-5898-87b3-e2a8edfddd1d] to "/home/runner/.julia/compiled/v1.10/InspectDR/jl_zzmLrF".
ERROR: LoadError: Creating a new global in closed module `__toplevel__` (`_devmode`) breaks incremental compilation because the side effects will not be permanent.
Stacktrace:
 [1] top-level scope
   @ ~/.julia/packages/InspectDR/cYUMk/src/InspectDR.jl:8

[BeastyBlacksmith]

As far as I understand it is only broken if you change the default backend, since then it is trying to load a package into Main at precompile time that is not a direct dependency of Plots

[BioTurboNick]

So, evaluating into Main during backend initialization has been something Plots has been doing for 6 years, and selecting a default initial backend during precompilation has been around for 1 year (JuliaPlots/Plots.jl#4566), but Julia 1.10 has broken it.

[vtjnash]

Sounds like it is implemented wrong for the current loading system. When first written, there probably wasn't PkgId yet and such. But eventually needed to be fixed to reference dependencies correctly in their manifest

[StefanKarpinski]

I understand that this is annoying, but I don't think we can reasonably guarantee that packages can do arbitrary eval shenanigans during precompilation and have it never break. Evaling into Main is a super sketchy thing to do and the fact that it ever worked during precompilation is quite dicey.