Fix inconsistent floating window z order across outputs

include/sway/input/seat.h

@@ -113,6 +113,12 @@ struct sway_seat {
 				// sway_keyboard_shortcuts_inhibitor::link
 
 	struct wl_list link; // input_manager::seats
+
+	// Used by sway_container.floating_order. This value will increment as
+	// floating windows request to be shown on top, this makes sure that a
+	// value can be assigned to a floating window that is guaranteed
+	// to be highter (ignoring overflow) than other floating windows.
+	uint32_t floating_counter;
 };
 
 struct sway_pointer_constraint {

include/sway/tree/container.h

@@ -113,6 +113,12 @@ struct sway_container {
 	// Hidden scratchpad containers have a NULL parent.
 	bool scratchpad;
 
+	// Value specifing in which order floating windows should be shown
+	// higher values means that the floating window should appear
+	// ontop of others. This variable is undefined if this container is not
+	// floating.
+	uint32_t floating_order;
+
 	float alpha;
 
 	struct wlr_texture *title_focused;

sway/desktop/render.c

@@ -996,8 +996,17 @@ static void render_floating_container(struct sway_output *soutput,
 	}
 }
 
+static int floating_order_compare (const void *a, const void *b) {
+	struct sway_container *a_container = *(struct sway_container **)a;
+	struct sway_container *b_container = *(struct sway_container **)b;
+
+	return a_container->floating_order - b_container->floating_order;
+}
+
 static void render_floating(struct sway_output *soutput,
 		pixman_region32_t *damage) {
+	list_t *floating = create_list();
+
 	for (int i = 0; i < root->outputs->length; ++i) {
 		struct sway_output *output = root->outputs->items[i];
 		for (int j = 0; j < output->current.workspaces->length; ++j) {
@@ -1010,10 +1019,19 @@ static void render_floating(struct sway_output *soutput,
 				if (floater->current.fullscreen_mode != FULLSCREEN_NONE) {
 					continue;
 				}
-				render_floating_container(soutput, damage, floater);
+				list_add(floating, floater);
 			}
 		}
 	}
+
+	list_qsort(floating, floating_order_compare);
+
+	for (int i = 0; i < floating->length; ++i) {
+		struct sway_container *floater = floating->items[i];
+		render_floating_container(soutput, damage, floater);
+	}
+
+	list_free(floating);
 }
 
 static void render_seatops(struct sway_output *output,

sway/input/seat.c

@@ -565,6 +565,8 @@ struct sway_seat *seat_create(const char *seat_name) {
 	}
 	seat->wlr_seat->data = seat;
 
+	seat->floating_counter = 0;
+
 	seat->cursor = sway_cursor_create(seat);
 	if (!seat->cursor) {
 		wlr_seat_destroy(seat->wlr_seat);

sway/tree/container.c

@@ -289,31 +289,49 @@ static struct sway_container *container_at_linear(struct sway_node *parent,
 	return NULL;
 }
 
+static int floating_order_compare (const void *a, const void *b) {
+	struct sway_container *a_container = *(struct sway_container **)a;
+	struct sway_container *b_container = *(struct sway_container **)b;
+
+	return a_container->floating_order - b_container->floating_order;
+}
+
 static struct sway_container *floating_container_at(double lx, double ly,
 		struct wlr_surface **surface, double *sx, double *sy) {
-	// For outputs with floating containers that overhang the output bounds,
-	// those at the end of the output list appear on top of floating
-	// containers from other outputs, so iterate the list in reverse.
-	for (int i = root->outputs->length - 1; i >= 0; --i) {
+	list_t *floating = create_list();
+
+	for (int i = 0; i < root->outputs->length; ++i) {
 		struct sway_output *output = root->outputs->items[i];
 		for (int j = 0; j < output->workspaces->length; ++j) {
 			struct sway_workspace *ws = output->workspaces->items[j];
 			if (!workspace_is_visible(ws)) {
 				continue;
 			}
-			// Items at the end of the list are on top, so iterate the list in
-			// reverse.
-			for (int k = ws->floating->length - 1; k >= 0; --k) {
+			for (int k = 0; k < ws->floating->length; ++k) {
 				struct sway_container *floater = ws->floating->items[k];
-				struct sway_container *container =
-					tiling_container_at(&floater->node, lx, ly, surface, sx, sy);
-				if (container) {
-					return container;
-				}
+				list_add(floating, floater);
 			}
 		}
 	}
-	return NULL;
+
+	list_qsort(floating, floating_order_compare);
+
+	struct sway_container *container = NULL;
+
+	// Items at the end of the list are on top, so iterate the list in
+	// reverse.
+	for (int i = floating->length - 1; i >= 0; --i) {
+		struct sway_container *floater = floating->items[i];
+		struct sway_container *current =
+			tiling_container_at(&floater->node, lx, ly, surface, sx, sy);
+		if (current) {
+			container = current;
+			break;
+		}
+	}
+
+	list_free(floating);
+	return container;
 }
 
 static struct sway_container *view_container_content_at(struct sway_node *parent,
@@ -837,6 +855,7 @@ void container_set_floating(struct sway_container *container, bool enable) {
 	if (enable) {
 		struct sway_container *old_parent = container->pending.parent;
 		container_detach(container);
+		container->floating_order = ++seat->floating_counter;
 		workspace_add_floating(workspace, container);
 		if (container->view) {
 			view_set_tiled(container->view, false);
@@ -1733,10 +1752,15 @@ void container_update_marks_textures(struct sway_container *con) {
 }
 
 void container_raise_floating(struct sway_container *con) {
+	struct sway_seat *seat = input_manager_current_seat();
 	// Bring container to front by putting it at the end of the floating list.
 	struct sway_container *floater = container_toplevel_ancestor(con);
 	if (container_is_floating(floater) && floater->pending.workspace) {
-		list_move_to_end(floater->pending.workspace->floating, floater);
+		// Don't raise if already on top
+		if (floater->floating_order != seat->floating_counter) {
+			floater->floating_order = ++seat->floating_counter;
+		}
+
 		node_set_dirty(&floater->pending.workspace->node);
 	}
 }

sway/tree/workspace.c

@@ -813,6 +813,8 @@ void workspace_add_floating(struct sway_workspace *workspace,
 	if (con->pending.workspace) {
 		container_detach(con);
 	}
+	struct sway_seat *seat = input_manager_current_seat();
+	con->floating_order = ++seat->floating_counter;
 	list_add(workspace->floating, con);
 	con->pending.workspace = workspace;
 	container_for_each_child(con, set_workspace, NULL);