tree/workspace: fix crash on dragging container to workspace edgebandicoot

Problem: when dragging a parent container to the right of its children,
sway crashes, the calculated insertion index could exceed the list
bounds. The move logic would compute an index based on the pre-removal
list state.

Solution: Clamp the insertion index to [0, length].

1 files changed, 5 insertions, 0 deletions

diff --git a/sway/tree/workspace.c b/sway/tree/workspace.c
index 733a002b..ddae8de4 100644
--- a/sway/tree/workspace.c
+++ b/sway/tree/workspace.c
@@ -842,6 +842,11 @@ struct sway_container *workspace_insert_tiling(struct sway_workspace *workspace,
 	if (config->default_layout != L_NONE) {
 		con = container_split(con, config->default_layout);
 	}
+	if (index < 0) {
+		index = 0;
+	} else if (index > workspace->tiling->length) {
+		index = workspace->tiling->length;
+	}
 	workspace_insert_tiling_direct(workspace, con, index);
 	return con;
 }