Conditional Loading of Packages

[TheCedarPrince]

Is your feature request related to a problem? Please explain.

I have noticed recently that using Javis seems to be taking much longer than it used to. I ran some benchmarks and it was somewhat concerning:

v0.1.5 Benchmarks:

julia> @time using Javis
 41.913861 seconds (37.30 M allocations: 2.000 GiB, 3.49% gc time)

v0.1.0 Benchmarks:

julia> @time using Javis
[ Info: Precompiling Javis [78b212ba-a7f9-42d4-b726-60726080707e]
 21.673696 seconds (12.55 M allocations: 715.007 MiB, 0.83% gc time)

We have currently doubled the compile time of Javis! 😱

Describe the solution you'd like

I would like to conditionally compile packages as they are needed. Obviously, some packages that are critical would always be loaded but I think we need to identify where the compile time issues come from.

Describe alternatives you've considered

Thanks to a suggestion from @mcabbott I think Requires.jl would help fix this problem.

[Wikunia]

Interesting idea but in that case the user would need to write using Gtk, right? Or cans that be avoided as well? I didn't really understand Requires.jl I guess

[TheCedarPrince]

From what I have read and understood about Requires.jl, I think having to write using Gtk can be avoided. I will have to research this a bit more to confirm.

[Sov-trotter]

So does it have it be something like

function __init__()
    @require Gtk="4c0ca9eb-093a-5379-98c5-f87ac0bbbf44" Base.show("Gtk Loaded")
end

Since Requires.jl reads

Suppose you've written a package called MyPkg. MyPkg has core functionality that it always provides; but suppose you want to provide additional functionality if the Gadfly package is also loaded. Requires.jl exports a macro, @require, that allows you to specify that some code is conditional on having both packages available.

But I don't think we need to perform anything apart from just delaying the loading part ?

[TheCedarPrince]

That is my understanding of what Requires.jl would do here. I haven't had much time to look into this. Would you be able to experiment with this functionality to decrease the precompile time @Sov-trotter? I'd be happy to provide support you in creating a PR. 🙂

[Wikunia]

We probably want this only for the image viewer as I assume Gtk requires the most. This assumption needs to be tested 😄 .
In general I believe that precompilation time isn't super important as it should be done only once for all users (except for developers)

Thanks for your comment @Sov-trotter and yeah if you're interested we appreciate your help 😉

[Sov-trotter]

Sorry I should've created a PR by now but I am running into the error.

Gtk-Message: 13:18:56.751: Failed to load module "canberra-gtk-module"
Gtk-Message: 13:18:56.751: Failed to load module "canberra-gtk-module"

I tried to fix Gtk based on the other issues on Gtk.jl. Almost bricked gnome in that process. :(

[TheCedarPrince]

Hey @Sov-trotter no worries! I have had that error before on Linux-based machines. What machine are you using? If you are using a linux based machine, this solution should assist: https://askubuntu.com/questions/208431/failed-to-load-module-canberra-gtk-module

[TheCedarPrince]

Closed due to inability to solve and fix at the moment. May reopen someday!