Ignore stale client commits on floating resize

pytest.ini

@@ -0,0 +1,2 @@
+[pytest]
+addopts = -n 4

scroll.lua

@@ -653,4 +653,27 @@ function scroll.add_callback(event, cb_func, cb_data) end
 --- @return integer
 function scroll.remove_callback(id) end
 
+---
+--- Returns true if there is an active animation running.
+---
+--- This is primarily intended for use via the IPC interface for testing and
+--- debugging. It is generally not useful when called synchronously within a
+--- Lua script, as animations only start after the script execution completes.
+---
+--- @return boolean
+---
+function scroll.animating() end
+
+---
+--- Returns true if there are pending transactions that haven't been applied yet.
+---
+--- This is primarily intended for use via the IPC interface for testing and
+--- debugging. It is generally not useful when called synchronously within a
+--- Lua script, as transactions are not processed while the script is running
+--- and blocking the main thread.
+---
+--- @return boolean
+---
+function scroll.pending_transactions() end
+
 return scroll

sway/desktop/xdg_shell.c

@@ -292,6 +292,20 @@ static const struct sway_view_impl view_impl = {
 	.destroy = destroy,
 };
 
+static bool is_commit_stale(struct sway_view *view, struct wlr_xdg_surface *xdg_surface) {
+	uint32_t latest_serial = 0;
+	if (xdg_surface->configure_idle != NULL) {
+		latest_serial = xdg_surface->scheduled_serial;
+	} else if (!wl_list_empty(&xdg_surface->configure_list)) {
+		struct wlr_xdg_surface_configure *configure =
+				wl_container_of(xdg_surface->configure_list.prev, configure, link);
+		latest_serial = configure->serial;
+	} else {
+		return false;
+	}
+	return xdg_surface->current.configure_serial < latest_serial;
+}
+
 static void handle_commit(struct wl_listener *listener, void *data) {
 	struct sway_xdg_shell_view *xdg_shell_view =
 		wl_container_of(listener, xdg_shell_view, commit);
@@ -341,20 +355,21 @@ static void handle_commit(struct wl_listener *listener, void *data) {
 			new_geo->height != view->geometry.height ||
 			new_geo->x != view->geometry.x ||
 			new_geo->y != view->geometry.y;
-
 	if (new_size) {
 		// The client changed its surface size in this commit. For floating
 		// containers, we resize the container to match. For tiling containers,
 		// we only recenter the surface.
 		memcpy(&view->geometry, new_geo, sizeof(struct wlr_box));
 		if (container_is_floating(view->container)) {
-			view_update_size(view);
-			// Only set the toplevel size the current container actually has a size.
-			if (view->container->current.width) {
-				wlr_xdg_toplevel_set_size(view->wlr_xdg_toplevel, view->geometry.width,
-					view->geometry.height);
+			if (!is_commit_stale(view, xdg_surface)) {
+				view_update_size(view);
+				// Only set the toplevel size the current container actually has a size.
+				if (view->container->current.width) {
+					wlr_xdg_toplevel_set_size(
+							view->wlr_xdg_toplevel, view->geometry.width, view->geometry.height);
+				}
+				transaction_commit_dirty_client();
 			}
-			transaction_commit_dirty_client();
 		}
 
 		view_center_and_clip_surface(view);

sway/lua.c

@@ -14,6 +14,7 @@
 #include "sway/desktop/launcher.h"
 #include "sway/ipc-server.h"
 #include "sway/desktop/transaction.h"
+#include "sway/server.h"
 
 #if 0
 static void print_table(lua_State *L, int index);
@@ -1727,7 +1728,20 @@ static int scroll_remove_callback(lua_State *L) {
 	return 0;
 }
 
+static int scroll_animating(lua_State *L) {
+	lua_pushboolean(L, animation_animating());
+	return 1;
+}
+
+static int scroll_pending_transactions(lua_State *L) {
+	bool pending = server.queued_transaction != NULL || server.pending_transaction != NULL ||
+			server.dirty_nodes->length > 0;
+	lua_pushboolean(L, pending);
+	return 1;
+}
+
 // Module functions
+/* clang-format off */
 static luaL_Reg const scroll_lib[] = {
 	{ "log", scroll_log },
 	{ "state_set_value", scroll_state_set_value },
@@ -1798,8 +1812,11 @@ static luaL_Reg const scroll_lib[] = {
 	{ "scratchpad_hide", scroll_scratchpad_hide },
 	{ "add_callback", scroll_add_callback },
 	{ "remove_callback", scroll_remove_callback },
+	{ "animating", scroll_animating },
+	{ "pending_transactions", scroll_pending_transactions },
 	{ NULL, NULL }
 };
+/* clang-format on */
 
 // Module Loader
 int luaopen_scroll(lua_State *L) {

sway/scroll.5.scd

@@ -2402,7 +2402,27 @@ local process_data = scroll.exec_process("kitty")
 	Removes a callback set earlier using *add_callback*. _id_ is the unique
 	identifier returned by *add_callback*.
 
-Examples:
+## TESTING AND DEBUGGING API
+
+These functions are primarily intended for use via the IPC interface (see
+*scroll-ipc*(7)) for testing and debugging purposes, and are generally not
+useful when called synchronously from standard Lua scripts or event callbacks.
+
+Because scroll's Lua integration executes scripts synchronously on the main
+compositor thread, the event loop is blocked during execution. This means that
+any compositor actions triggered by the script (such as applying window layouts
+or starting animations) will only occur after the script completes.
+Consequently, calling these functions synchronously within a script will not
+reflect the state changes of commands run immediately before them.
+
+*animating()*
+	Returns _true_ if there is an active animation running.
+
+*pending_transactions()*
+	Returns _true_ if there are pending transactions that haven't been applied
+	yet.
+
+## EXAMPLES
 
 Calling this script from the configuration file, you will get focus on every
 window that gets the *urgent* attribute:

tests/clients/wayland-client.c

@@ -19,6 +19,7 @@ struct client_state {
 	struct xdg_toplevel *xdg_toplevel;
 	struct wl_buffer *buffer;
 	int width, height;
+	int buffer_width, buffer_height;
 	void *shm_data;
 };
 
@@ -51,6 +52,14 @@ static void xdg_surface_configure(void *data, struct xdg_surface *xdg_surface, u
 	struct client_state *state = data;
 	xdg_surface_ack_configure(xdg_surface, serial);
 
+	if (state->buffer &&
+			(state->buffer_width != state->width || state->buffer_height != state->height)) {
+		wl_buffer_destroy(state->buffer);
+		state->buffer = NULL;
+		munmap(state->shm_data, state->buffer_width * 4 * state->buffer_height);
+		state->shm_data = NULL;
+	}
+
 	if (!state->buffer) {
 		int stride = state->width * 4;
 		int size = stride * state->height;
@@ -78,6 +87,8 @@ static void xdg_surface_configure(void *data, struct xdg_surface *xdg_surface, u
 		for (int i = 0; i < state->width * state->height; ++i) {
 			pixels[i] = 0xFF0000FF; // Blue
 		}
+		state->buffer_width = state->width;
+		state->buffer_height = state->height;
 	}
 
 	wl_surface_attach(state->surface, state->buffer, 0, 0);
@@ -86,7 +97,14 @@ static void xdg_surface_configure(void *data, struct xdg_surface *xdg_surface, u
 }
 static const struct xdg_surface_listener xdg_surface_listener = { xdg_surface_configure };
 
-static void xdg_toplevel_configure(void *data, struct xdg_toplevel *xdg_toplevel, int32_t width, int32_t height, struct wl_array *states) {}
+static void xdg_toplevel_configure(void *data, struct xdg_toplevel *xdg_toplevel, int32_t width,
+		int32_t height, struct wl_array *states) {
+	struct client_state *state = data;
+	if (width > 0 && height > 0) {
+		state->width = width;
+		state->height = height;
+	}
+}
 static void xdg_toplevel_close(void *data, struct xdg_toplevel *xdg_toplevel) {
 	exit(0);
 }