Package dependent code loading doesn't work in v0.7 ?

[jonathanBieler]

I'm trying to update Immerse to v0.7 and I'm getting an issue with this part that doesn't load at precompilation and triggers an error:

https://github.com/GiovineItalia/Compose.jl/blob/master/src/Compose.jl#L167

This mechanism seems to work fine in the REPL:

julia> using Cairo

julia> using Compose
[ Info: Loading Cairo backend into Compose.jl

julia> Compose.absolute_native_units
absolute_native_units (generic function with 4 methods)


julia> module A
           using Cairo
           using Compose
           
           import Compose.absolute_native_units            
       end
[ Info: Loading Cairo backend into Compose.jl
Main.A

But if I put the code above in a package, it fails to import absolute_native_units:

julia> using TestCompose
[ Info: Recompiling stale cache file /Users/jbieler/.julia/compiled/v0.7/TestCompose/Tl9GO.ji for TestCompose [c558b20d-ff79-52a3-ae8b-9e51a808e850]
┌ Warning: Package TestCompose does not have Compose in its dependencies:
│ - If you have TestCompose checked out for development and have
│   added Compose as a dependency but haven't updated your primary
│   environment's manifest file, try `Pkg.resolve()`.
│ - Otherwise you may need to report an issue with TestCompose
└ Loading Compose into TestCompose from project dependency, future warnings for TestCompose are suppressed.
WARNING: could not import Compose.absolute_native_units into TestCompose
[ Info: Loading Cairo backend into Compose.jl

Any way to fix this ? Disabling precompilation in Immerse maybe ?

Might be related to #250, but I'm not sure what's its status.

[tlnagy]

Do you have Compose and Cairo in TestCompose's REQUIRE file?

[jonathanBieler]

Yes, I also tried to add them in a toml file but I can't get rid of this warning, I'm not sure what's going on with that. Do you think that's the cause of the issue ?

[jonathanBieler]

To be clear my problem is: WARNING: could not import Compose.absolute_native_units into TestCompose not the Warning: Package TestCompose does not have Compose in its dependencies:.

[bjarthur]

might try reversing the order of the usings. Compose before Cairo.

[jonathanBieler]

That doesn't seem to make a difference, I'v put a couple of prints in the packages to try to understand what's going on. Compose init gets called twice but the first one doesn't load Cairo:

julia> using TestCompose
[ Info: Recompiling stale cache file /Users/jbieler/.julia/compiled/v0.7/TestCompose/Tl9GO.ji for TestCompose [c558b20d-ff79-52a3-ae8b-9e51a808e850]

"Compose init called" 
"TestCompose trying to import absolute_native_units" 
WARNING: could not import Compose.absolute_native_units into TestCompose

"Compose init called" 
[ Info: Loading Cairo backend into Compose.jl

[tlnagy]

"Compose init called"

Did you add the print statement to this function?

Compose.jl/src/Compose.jl

Lines 166 to 169 in 69b4d95

	function __init__()
	@require Cairo="159f3aea-2a34-519c-b102-8c37f9878175" link_cairo()
	@require Fontconfig="186bb1d3-e1f7-5a2c-a377-96d770f13627" link_fontconfig()
	end

This might be an issue with Requires.jl which we depend on for conditional loading of Cairo. In the init function we just load code that will get loaded when Cairo is loaded. This works fine in interactive environments, but I'm not sure if it works in packages that load both Cairo and Compose (your case).

[jonathanBieler]

Did you add the print statement to this function?

Yes. I think it's a problem of the sort indeed. I'll check if I can reproduce a simpler example that uses Requires.

[jonathanBieler]

I managed to make it work by calling link_cairo explicitly in Immerse:

@eval Compose begin import Cairo end
Compose.link_cairo()

I had to do a couple of changes.

[jonathanBieler]

Thanks !

[bjarthur]

@jonathanBieler might this problem with Immerse.jl be related to the scope of module search path mentioned in the Requires.jl README?

In the @require block, or any included files, you can use or import the package, but note that you must use the syntax using .Gadfly or import .Gadfly, rather than the usual syntax. Otherwise you will get a warning about Gadfly not being in dependencies.

either way, i'd suggest creating an issue over at Requires.jl which describes this problem.

i also went looking for an Immerse PR by you but couldn't find one.

[jonathanBieler]

@bjarthur I haven't made a PR yet, still have some issues with transitioning to the new iteration protocole:

https://github.com/JuliaGraphics/Immerse.jl/blob/master/src/compose.jl#L286