Fix CA transactions warnings

[tiennou]

This should fix the CA transaction warnings we have (at least the ones I saw).

I went pretty heavy-handed on the proxy thing, but I didn't want to make all QSTask's accessors to become main-thready-asyncy...

I'll check that I didn't forget some of the keypaths though (I haven't checked everything, and I don't think we have an easy indeterminate progress one anywhere).

It seems to also fix the flicker we had, so 👍.

[tiennou]

Check completed. I manually switched scanTask and it didn't fail.

[skurfer]

I assume we can close #2329?

[tiennou]

Ref #2275

[tiennou]

Sorry, that one slipped my radar. I'm not sure actually, #2329 does (IMHO) weird things[1] to tasks, and the 2 other changes are unrelated, so they might be needed. My run was mostly "background", so I might not have got some of the warnings that we can get when eg. actions are executed.

[1] I don't see how changing to a sync block can fix anything. At worst, you might improve the deadlock rate because now whatever caused the task view to update (like a notification) will be waiting on the main thread.

[skurfer]

I just did like it said and set CA_DEBUG_TRANSACTION, but I don’t remember exactly what I found or why I did things that way. It was a loooong time ago.

[skurfer]

Looking back, we do need those changes, or something like them, no? Those things shouldn’t be allowed to happen on a background thread.

[tiennou]

True, but if it's called on the main thread, it's the fault of whatever called them not on the main thread (that's how I consider everything in QSInterface). So IMHO those are not correct fixes per se.