lazily load Pkg

[KristofferC]

This is a bit of a hack to work around the fact that depending on Pkg is quite expensive in 1.11. Here, we only load it when checking the compatibility / install status of a backend and also skipping that when the backend is GR.jl (since we know that is compatible due to resolving together with Plots).

I'll admit this is kind of ugly and a bit of "TTFP hacking". However, I don't think Plots.jl should depend on a package manager at all so 🤷.

TTFP change 2.1s to 1.7s

[codecov]

Codecov Report

Attention: Patch coverage is 70.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 89.68%. Comparing base (fa65e7d) to head (c8d09df).
Report is 17 commits behind head on master.

Files	Patch %	Lines
src/backends.jl	70.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4955      +/-   ##
==========================================
- Coverage   89.77%   89.68%   -0.09%     
==========================================
  Files          40       40              
  Lines        8780     8801      +21     
==========================================
+ Hits         7882     7893      +11     
- Misses        898      908      +10     

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[isentropic]

Not sure if we even need to depend on pkg given v2 and PlotsBase https://github.com/JuliaPlots/Plots.jl/tree/v2/PlotsBase

[KristofferC]

PlotsBase does the same:

Plots.jl/PlotsBase/src/backends.jl

Line 45 in f32247a

get(Pkg.dependencies(), pkg_id.uuid, (; version = nothing)).version

But with extensions the compat should be enforced and maybe this code is not needed, or?

[isentropic]

I dont think this function is needed at all now

Plots.jl/PlotsBase/src/backends.jl

Line 27 in f32247a

function _check_installed(pkg::Union{Module,AbstractString,Symbol}; warn = true)

but lets wait for @BeastyBlacksmith to confirm

[BeastyBlacksmith]

Thats true, that code can go in v2. However for the 1.x series we would need to up the julia compat, since pkgversion requires julia 1.9+

[KristofferC]

since pkgversion requires julia 1.9+

It is easy to read the project file of the package and extract the version. I just didn't remember when pkgversion was introduced.

[KristofferC]

(Looking forward to v2 which seems to have a great design avoiding these type of "hacks")