Reloading functions, but not constants, from packages?

[timholy]

When developing modules/packages, reload() is often helpful for testing changes without having to restart the REPL. However, one issue is that

myvar = MyModule.Constructor(args...)
# make changes
reload("MyModule")
MyModule.runtest(myvar)

fails, because you have to re-create myvar. If you have variables that interact across packages, or take a long time to initialize (e.g., require nontrivial calculation), this can be a bit of a pain.

With a bit of social engineering, it seems like it should be possible to support something like reload("MyModule", constants=false). The idea is that packages wanting to support this functionality would be organized something like this:

MyModule/
    src/
        MyModule.jl           # loads everything
        constants.jl           # all type definitions and constants go here
        MyModuleCode.jl   # loads everything except constants.jl
        file1.jl
        file2.jl
        ...

From this gist, here's a demo session:

julia> import MyModule

julia> val = MyModule.MyType(7)
MyType(7)

julia> MyModule.bigger(val)
MyType(8)

julia> reload("MyModule")
Warning: replacing module MyModule

julia> MyModule.bigger(val)
ERROR: no method bigger(MyType,)

julia> val = MyModule.MyType(7)
MyType(7)

julia> MyModule.bigger(val)
MyType(8)

julia> eval(MyModule, :(include("MyModuleCode.jl")))
# methods for generic function bigger
bigger(x::MyType) at /tmp/MyModule/src/file1.jl:3

julia> MyModule.bigger(val)
MyType(8)

[quinnj]

Seems like the functionality here is achieved through the new workspace() method; unless we still want to tweak reload?

[quinnj]

Please reopen if tweaking reload is desired.

[timholy]

Perhaps even more relevantly, Julia now has much better smarts about detecting that types haven't changed. Try including a test file like

immutable MyType
    a::Int
end

f(::MyType) = 1

and then tweak the definition of f. You'll succeed, whereas formerly it would have complained about redefinition of MyType. In contrast, if you change MyType you'll still get an error (as well you should).

So yes, this can indeed be closed. Thanks for doing the cleaning!

[LMescheder]

However, currently in julia v0.5-rc4 if I put

module A
immutable MyType
    a::Int
end

f(::MyType) = 1
end

in a file and want to change A.f, I have to reinitialize all variables of type A.MyType, which can be very inconvenient... Is there a workaround for this?

[cstjean]

@LMescheder I hit the same problem with 0.5, and just wrote ClobberingReload.jl to solve it. It hasn't been tested much yet, but if you want to give it a try, it should solve your problem. Let me know if you have any issues.