Fix crash when focusing from fullscreen in an invalid direction

* Fullscreen a view
* Run `focus <direction>` where there is no output in that direction

The output returned was rightfully NULL, which needs to be handled.

1 files changed, 3 insertions, 0 deletions

diff --git a/sway/commands/focus.c b/sway/commands/focus.c
index 83b8c64a..58721b7e 100644
--- a/sway/commands/focus.c
+++ b/sway/commands/focus.c
@@ -102,6 +102,9 @@ static struct sway_node *node_get_in_direction(struct sway_container *container,
                 // Fullscreen container with a direction - go straight to outputs
                 struct sway_output *output = container->workspace->output;
                 struct sway_output *new_output = output_get_in_direction(output, dir);
+                if (!new_output) {
+                        return NULL;
+                }
                 return get_node_in_output_direction(new_output, dir);
         }
         if (dir == MOVE_PARENT) {