Wierd bug with a nested checkbox

[yakir12]

Why does this (albeit contrived) example not work?

using GtkReactive, Gtk.ShortNames
w = Window("a")
a = button("a")
b = Box(:h)
push!(b, a)
foreach(a) do _
    cb = checkbox(rand(Bool))
    foreach(println, cb)
    push!(b, cb)
end
push!(w, b)
showall(w)

Running this builds the checkbox and prints the boolean, but then it dies (pressing on the button doesn't produce any additional checkboxes nor prints the booleans). Rerunning this within the same session halts the Julia session and I need to pkill julia or Ctrl-Z.
I'm on Version 0.6.0-dev.1393 (2016-12-09 01:03 UTC)

[timholy]

I think I've seen something similar with a much more complicated example (one so complicated I made almost no headway debugging it). In my case it seemed to fall into a cycle and kept trying to create new windows.

For reference (and because I'm in the middle of something else and don't have time to pursue it further), the following is a workaround:

using GtkReactive, Gtk.ShortNames
w = Window("a")
a = button("a")
b = Box(:h)
push!(b, a)

function create_checkbox()
    global cb
    global b
    cb = checkbox(rand(Bool))
    push!(b, cb)
end

updater = map(signal(a); init=nothing) do _
    @schedule println("clicked")
    @schedule create_checkbox()
    nothing
end
push!(w, b)
showall(w)

This adds a new checkbox each time you click the button. (You have to showall(w) to see it, if memory serves.)

It might be worth pinging @JobJob and @shashi about this, since this could be a Reactive issue.

[yakir12]

Thanks for the workaround! I'll try it within the framework this is intended for. It helped me with my specific case (with some modifications). But it would be good if this just worked.

[JobJob]

The equivalent code in Interact is also broken:

using Interact
a = button("a")
foreach(signal(a)) do _
    cb = checkbox(rand(Bool))
    foreach(println, signal(cb))
    display(cb)
end
display(a)

that was an issue in Reactive. I've fixed that in Pkg.checkout("Reactive", "job/queue-restart-issues") but it didn't seem to fix the OP here, I'm not sure why. It does seem to be a bug in Reactive, because Base.n_avail(Reactive._messages) is the same as the number of times the "a" button is pressed - indicating that Reactive isn't processing the message queue (push!es to signals) correctly. Anyway, will have another look at it tomorrow.

[JobJob]

Ok I've fixed the issue in the OP on that branch now, but I'm not 100% happy with the solution, will see if I can improve it tomorrow. Let me know how you go with it.

[JobJob]

Oh note, I also needed to add another showall(w) after adding the checkbox

...
foreach(a) do _
    cb = checkbox(rand(Bool))
    foreach(println, cb)
    push!(b, cb)
    showall(w)
end
...

[yakir12]

@JobJob's solution fixed both the example above and my actual code (I had to Pkg.checkout("Reactive", "queue-restart-issues"), without the job/).
I'll leave the closing to you guys, since the fix resides in Reactive, and not in GtkReactive, and it hasn't been merged yet.

[JobJob]

Thanks for the minimal reproduction @yakir12 - I'd been running into this issue the last few days, but wasn't sure exactly what was up - this helped a lot!

[yakir12]

Spoke too soon. I'll hopefully be back with an example.

[yakir12]

I wrote a simplified version of my code. But I can't reproduce the same faulty behavior I have in my real code in this simplified version. I'll try to strip off all the layers of complexity from my real code and see what causes the problem. I'll be back...

[JobJob]

So I take it from #33 Reactive can breathe easy, this is resolved with the fix above?

[yakir12]

That is correct.