Use only state to check fullscreen when no configured output is set

[Lompik]

This patch only affects "fullscreen" option under wayland.
It seems that tracking window outputs viaforeign_toplevel.output_enter is not appropriate while foreign_toplevel.state rigorously tracks active(focused)/fullscreen state.
Some compositors (wlroots/sway in my case) consider that a window starting fullscreen does not "become" visible, it already is. So foreign_toplevel.output_enter is not sent if the window starts in fullscreen.
That's a problem as toplevel->output_list ends up empty and wl_have_fulscreen_window returns false even if the window is "active" and "fullscreen".
This patch keeps the behavior if a configured output is set.

Here's an example with "mpv --fullscreen"

[3776372.004] {Default Queue} zwlr_foreign_toplevel_manager_v1#3.toplevel(new id zwlr_foreign_toplevel_handle_v1#4278190093)
[3776372.018] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.title("1.mkv - mpv")
[3776372.022] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.state(array[4])       -- mpv active
[3776372.024] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190094.state(array[0])       -- previous window -> not active
[3776372.027] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.state(array[8])       -- mpv fullscreen
[3776372.029] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.app_id("mpv")
[3776372.031] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.done()
[3776372.052] {Default Queue}  -> wl_display#1.sync(new id wl_callback#19)
[3776372.056] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190094.done()
[3776372.462] {Display Queue} wl_display#1.delete_id(19)
[3776372.481] {Default Queue} wl_callback#19.done(28834)
 --- toplevel->output_list is empty here, wl_have_fulscreen_window always false before this patch, notification are always displayed :(
 --- Press f to unfullscreen mpv
[3781447.916] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.state(array[4])
[3781447.951] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.done()
[3781448.025] {Default Queue}  -> wl_display#1.sync(new id wl_callback#19)
[3781448.095] {Display Queue} wl_display#1.delete_id(19)
[3781448.106] {Default Queue} wl_callback#19.done(28836)
[3781458.333] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.output_enter(wl_output#10)   -- output_enter finally ! fills toplevel->output_list
[3781458.349] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.done()
 --- Press f to fullscreen mpv
 --- before and after this patch, notification visibility depends on fullscreen option
[3787032.504] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.state(array[8])
[3787032.546] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.done()
[3787032.638] {Default Queue}  -> wl_display#1.sync(new id wl_callback#19)
[3787032.730] {Display Queue} wl_display#1.delete_id(19)
[3787032.742] {Default Queue} wl_callback#19.done(28839)
[3793144.609] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.state(array[4])
[3793144.645] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190088.state(array[4])
[3793144.656] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.done()
[3793144.729] {Default Queue}  -> wl_display#1.sync(new id wl_callback#19)
[3793144.742] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190088.done()
[3793144.874] {Display Queue} wl_display#1.delete_id(19)
[3793144.884] {Default Queue} wl_callback#19.done(28844)
[3793777.390] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190088.state(array[0])
[3793777.428] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.state(array[8])
[3793777.439] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190088.done()
[3793777.455] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.done()
[3793777.540] {Default Queue}  -> wl_display#1.sync(new id wl_callback#19)
[3793777.872] {Display Queue} wl_display#1.delete_id(19)
[3793777.906] {Default Queue} wl_callback#19.done(28848)
[3793963.593] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190093.closed()
[3793963.630] {Default Queue}  -> zwlr_foreign_toplevel_handle_v1#4278190093.destroy()
[3810540.442] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190088.state(array[4])
[3810540.480] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190088.done()

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[fedang]

Sorry for the late reply. Unfortunately i cannot test the changes right now.

[fedang]

Sorry for the late reply. Unfortunately i cannot test the changes right now.

[fwsmit]

This change looks fine to me.
I wonder if the behavior of sway is a bug. It seems logical to send an output enter signal even when the window starts fullscreen.

[Lompik]

i tested on labwc and we do get the output_enter event.

[ 629159.563] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190080.state(array[0])
[ 629159.572] {Default Queue} zwlr_foreign_toplevel_manager_v1#3.toplevel(new id zwlr_foreign_toplevel_handle_v1#4278190082)
[ 629159.575] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190082.app_id("mpv")
[ 629159.577] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190082.title("1.mkv - mpv")
[ 629159.580] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190082.state(array[4])
[ 629159.582] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190082.state(array[8])
[ 629159.584] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190082.output_enter(wl_output#9)
[ 629159.586] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190080.done()
[ 629159.588] {Default Queue} zwlr_foreign_toplevel_handle_v1#4278190082.done()

sway should probably send that output_enter event too. Without that dunst cannot map apps to outputs and until then setting monitor=.. & fullscreen=... in dunst won't work on sway.
I realize now that this patch only works where there are more than 1 screen (and user don't set a monitor=..) : it seems that get_configured_output always return non-NULL if there is only one screen.
However relying on state changes only avoids the bugs that output_enter/leave compositors could have.

[fedang]

So this patch fixes an edge case in sway that happens only if there are more than one screens? I will merge without problem, but maybe that should be investigated with sway? (Or maybe we messed up somewhere else?)

[Lompik]

I submitted swaywm/sway#9000 to sway and trying to fix it

[fedang]

should I merge in the meantime or do we wait for sway response?

[Lompik]

I'll actually close this as being an edge case and more of a sway issue. We can revisit later if more people are affected.