Let a new window pick its own size instead of forcing a guessed placeholder

Root-caused "windows spawn small and square, not remembering placement or
size": new_managed_window hardcoded a fresh toplevel's geometry to 800x632
before the client had said anything about its own preferred size, and
sync_geometry forced that guess onto the client's very first
xdg_toplevel::configure unconditionally. Per xdg-shell, size: None on that
first configure is how every mainstream compositor lets a client pick its
own natural size instead; this one never did, so every app converged on
the same placeholder rectangle regardless of what it would have chosen.

Window::size_is_provisional marks a size that really was just the guess
(not a remembered geometry, a rule's explicit geometry action, or a
maximize/phone-mode fill, none of which are guesses). sync_geometry sends
size: None for such a window's first configure; a new adopt_provisional_size,
called from the commit handler, adopts the client's own real first size
into Window::geometry the moment it commits one, clamping only position so
a bigger-than-guessed window can't hang off its monitor's edge.

Live-verified in a nested compositor: a zenity dialog now renders at its
own compact natural size instead of being stretched to the old guess.

1 files changed, 1 insertions, 0 deletions

diff --git a/crates/wayland/src/udev/platform.rs b/crates/wayland/src/udev/platform.rs
index d7132ee..732fbc2 100644
--- a/crates/wayland/src/udev/platform.rs
+++ b/crates/wayland/src/udev/platform.rs
@@ -269,6 +269,7 @@ impl UdevPlatform {
             border_side_buffers: HashMap::new(),
             color_filter_buffers: HashMap::new(),
             last_synced_size: HashMap::new(),
+            provisional_size: HashSet::new(),
             pending_size_configure: HashMap::new(),
             pending: pending.clone(),
             bound_keys: Rc::new(bound_keys.iter().cloned().collect::<HashSet<_>>()),