niri does not send a wl_pointer::enter event when layer surfaces spawn on the pointer

[zeroeightysix]

I'm writing a wayland client using sctk and running into the problem that pointer events aren't getting through if the surface's input region covers the pointer when it spawns. Sctk will refuse to pass on any motion events until it has seen a wl_pointer::enter:

https://github.com/Smithay/client-toolkit/blob/4cf0deff833012bc93e3b58d0f1c1c33bc0ee8bf/src/seat/pointer/mod.rs#L372

The wording of wl_pointer::enter:

"Notification that this seat's pointer is focused on a certain surface."

seems to suggest that this really does need to be sent once the compositor decides that any new pointer events will go to this surface, and not only when the pointer moves from one region to another?

[YaLTeR]

It works for me with fuzzel. It gets a wl_pointer.enter() immediately if it spawns under the pointer.

[zeroeightysix]

Hm, I might be making a mistake then. I'll see if I can get a minimal reproduction example.

[zeroeightysix]

I made this example which reproduces the behaviour for me: https://github.com/zeroeightysix/niri-reproduce-missing-wl-enter

Notably, I did get the enter event if the surface contents are drawn using shm (first commit) but not when using wgpu (second commit).

Am I just setting up rendering wrong?

[YaLTeR]

Not sure; I'm not very familiar with wgpu. Could you test on other compositors?

[zeroeightysix]

• I get the Enter event immediately on sway
• I get the Enter event along with the first motion event on cosmic