From 6382fe146926019677464b7b58b5634ace4bc61a Mon Sep 17 00:00:00 2001
From: codegax <14095200+codegax@users.noreply.github.com>
Date: Sat, 2 May 2026 16:10:00 -0600
Subject: [PATCH] tree/load_layout: give placeholder leaves L_HORIZ layout

A placeholder leaf has view==NULL, so arrange_container routes it
to its view-less branch, which calls arrange_children with the
container's layout. arrange_children asserts on L_NONE, so a
plain { swallows: [...] } JSON entry crashed assert-enabled
builds before any window could match.

Default the layout to L_HORIZ when JSON does not specify one.
The placeholder has no children, so the iteration short-circuits
without rendering anything until promoted.
---
 sway/tree/load_layout.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/sway/tree/load_layout.c b/sway/tree/load_layout.c
index e1addaecf..10f26d3c5 100644
--- a/sway/tree/load_layout.c
+++ b/sway/tree/load_layout.c
@@ -386,10 +386,12 @@ static struct sway_container *build_node(struct json_object *obj,
 		c->swallows = sw;
 		// Retained so IPC can echo it verbatim for round-trip.
 		c->swallows_json = json_object_get(swallows_v);
+		// arrange_children asserts on L_NONE; placeholders end up there
+		// via the view-less branch even with no children.
+		if (c->pending.layout == L_NONE) {
+			c->pending.layout = L_HORIZ;
+		}
 	} else {
-		// Leaf without swallows is an empty split with no children. i3 does
-		// not produce these; treat as an error to avoid silently leaving
-		// orphaned containers.
 		*error_out = format_str("append_layout: node has neither nodes nor "
 				"swallows");
 		free_transient_subtree(c);