Static compilation doesn't use __init__

[omus]

It appears that static compilation does not call the __init__. Take the two modules below as an example:

module StaticFail

export @process

# global ENABLED = true  # static compilation works if I uncomment out this line
function __init__()
    global ENABLED = true
end

macro process(expr)
    ENABLED && return esc(expr)
    error("ENABLED is not set")
end

end

module StaticFailDemo

using StaticFail
export demo
demo() = @process 1 + 1

end

Calling demo() from within the REPL works as expected with and without pre-compilation but static compilation produces the following exception:

...
LoadError("sysimg.jl",381,LoadError("~/Development/Julia/0.5/base/userimg.jl",1,LoadError("~/.julia/v0.5/StaticFailDemo/src/StaticFailDemo.jl",5,UndefVarError(:ENABLED))))
ERROR: LoadError: failed process: Process(`~/Development/Julia/0.5/usr/bin/julia -C native --output-ji /tmp/sys.ji --output-o /tmp/sys.o -J /tmp/inference.ji --startup-file=no sysimg.jl`, ProcessExited(1)) [1]

[JeffBezanson]

This is intentional; when code is only being compiled we don't consider it to be at run time. The reasoning was that __init__ is often used by a library to discover something about its run time environment on startup, and we didn't want compiled libraries to bake-in information about the compile time environment instead.

It's also worth nothing that the same error would happen if you used @process within the StaticFail module, since macros run before the module is closed and so before __init__ runs. So having macros depend on __init__ is a bit dodgy in general.

[vtjnash]

Yes. I also confirmed this works with incremental compilation, as intended.

[omus]

For some reason I was under the impression that __init__ would run at compile time as well as run time. The global I defined should actually be defined at the top level. Thanks for clearing things up.

[StefanKarpinski]

Should this be documented somewhere?

[vtjnash]

yes, it does seem like http://docs.julialang.org/en/latest/manual/modules/#module-initialization-and-precompilation may lead someone to expect otherwise

[StefanKarpinski]

Reopened as a documentation issue.