contain client fullscreen inside kick; decouple from the host window

a client's fullscreen request used to be mirrored onto the host window
via libdecor, but labwc 0.9.8 expires its 100 ms configure deadline under
load and then applies "move but keep old size" permanently -- the
enlarged image anchored at the old origin with black margins.  the mirror
is gone: a client's fullscreen now fills kick's output only, leaving the
host window alone.  fullscreening the host remains an explicit act
(prefix+F11 or the compositor), and the host-to-clients propagation is
unchanged.

README.md

@@ -268,16 +268,19 @@ browser's `F11`).
 
 ## Fullscreen
 
-Fullscreen mirrors between the host window and the clients:
+## Fullscreen
+
+Fullscreening the kick window and fullscreening a client are independent:
 
 - Fullscreen the kick window (your host compositor's fullscreen keybinding,
-  an app's own `F11`, or `Alt+F11`) and every window of every tab -- mains
+  or `Alt+F11`) and every window of every tab -- mains and stacked
-  and stacked tab-group members alike -- is told it is fullscreen, so
+  tab-group members alike -- is told it is fullscreen, so clients drop
-  clients drop their decorations and fill the screen.
+  their decorations and fill the screen.
-- A client that requests fullscreen itself (e.g. a video player) also
+- A client that requests fullscreen itself (e.g. a video player) fills the
-  fullscreens the kick host window.
+  kick window's content only: the host window itself stays exactly where
-- Leaving fullscreen returns every window to maximized (X11 tab-group
+  and how it is. Use `Alt+F11` as well if you want the whole monitor.
-  members keep their own geometry).
+- Leaving host fullscreen returns every window to maximized (X11
+  tab-group members keep their own geometry).
 
 ## Standalone mode
 

kick.c

@@ -2642,12 +2642,13 @@ static void handle_request_fullscreen(struct wl_listener *listener, void *data)
     if (!toplevel->base->initialized) return;
     /* wlroots 0.19 emits request_fullscreen with NULL data; the direction
        lives in toplevel->requested.fullscreen.  Honor the client's request
-       and mirror it onto the host window: a fullscreen client fills the
+       within kick only: the window fills our output while the host window
-       host window, and an un-fullscreen client puts it back. */
+       itself is left alone.  Fullscreening the host window is a separate,
+       explicit act (prefix+F11 or the compositor), which propagates back
+       down through clients_set_fullscreen(). */
     bool fs = toplevel->requested.fullscreen;
     wlr_xdg_toplevel_set_fullscreen(toplevel, fs);
     kick_log(KICK_LOG_INFO, "client fullscreen=%d\n", fs);
-    host_queue_fullscreen(fs);
 }
 
 /* Propagate the host window's fullscreen state onto every client -- each
@@ -3644,11 +3645,10 @@ static void handle_xs_request_fullscreen(struct wl_listener *listener,
     struct kick_app *app = wl_container_of(listener, app, request_fullscreen);
     struct wlr_xwayland_surface *xs = app->xsurface;
     if (!xs) return;
-    /* Mirror onto the host window like the xdg path. */
+    /* Same containment as the xdg path: fullscreen stays inside kick. */
     bool fs = xs->fullscreen;
     wlr_xwayland_surface_set_fullscreen(xs, fs);
     kick_log(KICK_LOG_INFO, "client fullscreen=%d\n", fs);
-    host_queue_fullscreen(fs);
 }
 
 static void handle_xs_request_configure(struct wl_listener *listener,
@@ -5766,6 +5766,7 @@ static void host_teardown_window(void) {
 static void host_frame_configure(struct libdecor_frame *frame,
                                  struct libdecor_configuration *config,
                                  void *data)
+{
     (void)data;
     int width = 0, height = 0;
     bool size_ok =
@@ -6361,8 +6362,8 @@ static bool process_key_event(uint32_t time, uint32_t key, uint32_t state,
     /* Function keys are not grabbed (prefix+F11 above is the one exception):
         they pass through to the focused client, which may have its own
         bindings (e.g. a browser's F11 fullscreen request, which
-        handle_request_fullscreen mirrors onto the host window).  Frame dumps
+        handle_request_fullscreen contains inside kick).  Frame dumps are
-        are available via SIGUSR1 instead. */
+        available via SIGUSR1 instead. */
     /* Alt+Up / Alt+Down cycle tabs.  Grabbed so the focused client never
        sees them.  The host sends a single physical press, so repeats are
        synthesized by kbd_repeat_start(); subsequent host presses of an

tests/test_smoke.py

@@ -1484,18 +1484,22 @@ def test_function_keys_pass_through(session):
     assert session.proc.poll() is None
 
 
-def test_client_fullscreen_round_trip(session):
+def test_client_fullscreen_stays_inside_kick(session):
-    """A client's fullscreen request is honored and mirrored onto the host
+    """A client's fullscreen request is honored within kick but never
-    window; the host configure then propagates fullscreen to every tab.
+    mirrored onto the host window: wltest toggles xdg_toplevel fullscreen
-    wltest toggles xdg_toplevel fullscreen on the 'F' key, so tap it and
+    on the 'F' key, so tap it and check only the client-side state moves."""
-    watch both directions of the mirror."""
     session.wait_any_active()
     session.tap(F)
-    session.wait_for("host fullscreen=1")
+    session.wait_for("client fullscreen=1")
-    session.wait_for("clients fullscreen=1")
+    time.sleep(0.6)  # give a wrong mirror time to show up in the log
+    assert "host fullscreen=" not in session.read_log(), \
+        "client fullscreen leaked onto the host window"
+    assert "clients fullscreen=" not in session.read_log(), \
+        "client fullscreen propagated to other tabs"
     session.tap(F)
-    session.wait_for("host fullscreen=0")
+    session.wait_for("client fullscreen=0")
-    session.wait_for("clients fullscreen=0")
+    time.sleep(0.4)
+    assert "host fullscreen=" not in session.read_log()
     assert session.proc.poll() is None