Prefixing method with module name breaks code on 0.4.0

[joa-quim]

Example:

0.3.4

julia> methods(cdCreateCanvas)
#1 method for generic function "cdCreateCanvas":
cdCreateCanvas(context::Ptr{cdContext},data::Ptr{None}) at C:\programs\Gits\IUP.jl\src\libcd.jl:269

0.4.0

julia> methods(cdCreateCanvas)
#1 method for generic function "cdCreateCanvas":
cdCreateCanvas(context::Ptr{IUP_CD.cdContext},data::Ptr{Union()}) at C:\programs\Gits\IUP.jl\src\libcd.jl:269

which later breaks the code (that works in 0.3.4) with

ERROR: `cdCreateCanvas` has no method matching cdCreateCanvas(::Ptr{IUP_CD.cdContext}, ::Ptr{Void})
Closest candidates are:
  cdCreateCanvas(::Ptr{IUP_CD.cdContext}, ::Ptr{Union()})

[ivarne]

Usually issues such as this is much easier to fix if we get a (minimal) reproducible example that can be pasted into a REPL session. You seem to be referencing IUP.jl, and as it requires binary dependencies, it is kind of a hassle to install just to debug this issue.

[ivarne]

Sometimes issues like this can be caused by loading the same module twice, eg with reload. Can you try the examples again in a new session?

[joa-quim]

Yes, it happens with IUP and that's why I didn't try to find a small set of commands that reproduce the problem. However, I do recall that there was a post or an issue that referenced this issue not long time ago. I just wasn't able to find it again. And no, it's not a double module loading thing. It happens right on the first call.

[Keno]

This isn't a bug. Void, which used to be Union() is now the type of nothing, so the second argument is the problem.

[tkelman]

Looks like Compat.jl might need some code to help packages deal with the Void change?

[Keno]

Using Ptr{Void} will work on both versions, as long as it's done everywhere.

[joa-quim]

Sorry, a bit too concentrated info to me. You mean changing Ptr{None} to Ptr{Void} in https://github.com/joa-quim/IUP.jl/blob/master/src/libcd.jl#L269 ?

If I do so, I don't get the previous error but instead simply (after loading an image)

Please submit a bug report with steps to reproduce this fault, and any error messages that follow (in their entirety). Thanks.
Exception: UNKNOWN at 0x32f1160 --

In case someone wants to try (needs to install IUP), It occurs with (im_view is an example in the examples dir)

using im_view_;
im_view()

[Keno]

Yes, that's what I mean. Does it also segfault on 0.3?

[joa-quim]

No, 0.3 runs fine

[Keno]

Ok, I suspect than that doing the change is not the problem, but that there is some other bug causing the segfault. Are you able to get a backtrace.

[joa-quim]

Sorry, no. That's the only error message I get (it's a Win build btw).

[Keno]

Ok, I can take a look tomorrow and see if I can reproduce.

[JeffBezanson]

IUP issue opened: https://github.com/joa-quim/IUP.jl/issues/1