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, 20 insertions, 0 deletions

diff --git a/crates/core/src/window.rs b/crates/core/src/window.rs
index 21faeff..cc841b1 100644
--- a/crates/core/src/window.rs
+++ b/crates/core/src/window.rs
@@ -244,6 +244,25 @@ pub struct Window {
     /// This window's global-menu D-Bus address, if the client has exported
     /// one. See [`GlobalMenu`]'s own doc comment.
     pub global_menu: Option<GlobalMenu>,
+    /// Set by `WindowManager::add_window` when `geometry`'s size just came
+    /// from `SmartPlacement`'s own guessed default (`Window::new`'s
+    /// `640x480`, or whatever a backend hardcodes before a client has said
+    /// anything about its own preferred size) rather than a deliberate
+    /// decision - a remembered size, a rule's explicit `geometry` action,
+    /// or a maximize/phone-mode fill. `false` for all three of those, since
+    /// there is nothing provisional about a size someone actually chose.
+    ///
+    /// A backend reads this once, right after `add_window` returns, to
+    /// decide whether the *client's own* first real committed size should
+    /// be allowed to win once it arrives (see `crates/wayland/src/state/
+    /// geometry.rs`'s own use of this) - reported live as "windows always
+    /// spawn small and square, not remembering placement or size": every
+    /// new toplevel was forced, via its very first `xdg_toplevel.configure`,
+    /// into this guessed placeholder size regardless of what the
+    /// application itself would have preferred, which is why every app
+    /// converged on the same generic footprint instead of its own natural
+    /// one.
+    pub size_is_provisional: bool,
 }
 
 impl Window {
@@ -281,6 +300,7 @@ impl Window {
             rules_applied: false,
             anim_from: None,
             global_menu: None,
+            size_is_provisional: false,
         }
     }
 }