Hmm I'm concerned about using "transient" in the API docs and code. "Transient" is a descriptory adjective that means "temporary", i.e. if a window is a transient to some other window, it communicates two things: The association to the other window, and the expectation that this window is not permanent and shouldn't be treated as such. Now if the latter is the semantics we want to bake into the protocol, we should make that clear in the docs and consider misuse a bug (i.e. document that it's wrong to have a window with a parent if the window isn't temporary). Otherwise we shouldn't use "transient".

In D1779#33666, @hein wrote:

Now if the latter is the semantics we want to bake into the protocol, we should make that clear in the docs and consider misuse a bug (i.e. document that it's wrong to have a window with a parent if the window isn't temporary). Otherwise we shouldn't use "transient".

Transient in the context of windowing system has the meaning parent-child relationship. That's the only usage of the word I know. E.g. see https://en.wikipedia.org/wiki/Transient_%28computer_programming%29#X

On Wayland the situation is exactly the same and what this API provides is a parent-child relationship - which is a transient. Following the description of Wikipedia the child window will not outlife the parent window, thus it's a "transient" or a "temporary" window.

Just for the record: Martin's reply convinced me, so +1 after the fact. Sorry for this slipping through the cracks.

Now that this in I'll try to implement XWindowsTasksModel-like transient handling in libtaskmanager on Wayland soon (next week probably) and put it up for review.