Fix scratchpad fullscreen behavior and crash

When setting fullscreen on a hidden scratchpad container, there was a
check to see if there was an existing fullscreen container on the
workspace so it could be fullscreen disabled first. Since the workspace
is NULL, it would cause a SIGSEGV. This adds a NULL check to avoid the
crash.

This also changes the behavior of how fullscreen is handled when adding
a container to the scratchpad or changing visibility of a scratchpad
container to match i3's. The behavior is as follows:
- When adding a container to the scratchpad or hiding a container back
  into the scratchpad, there is an implicit fullscreen disable
- When setting fullscreen on a container that is hidden in the
  scratchpad, it will be fullscreen when shown (and fullscreen disabled
  when hidden as stated above)
- When setting fullscreen global on a container that is hidden in the
  scratchpad, it will be shown immediately as fullscreen global. The
  container is not moved to a workspace and remains in the
  scratchpad. The container will be visible until fullscreen disabled
  or killed. Since the container is in the scratchpad, running
  `scratchpad show` or `move container to scratchpad` will have no
  effect

This also changes `container_replace` to transfer fullscreen and
scratchpad status.

1 files changed, 9 insertions, 0 deletions

diff --git a/sway/commands/move.c b/sway/commands/move.c
index f642f023..4ebc949b 100644
--- a/sway/commands/move.c
+++ b/sway/commands/move.c
@@ -395,6 +395,11 @@ static struct cmd_results *cmd_move_container(int argc, char **argv) {
 		container = workspace_wrap_children(workspace);
 	}
 
+	if (container->fullscreen_mode == FULLSCREEN_GLOBAL) {
+		return cmd_results_new(CMD_FAILURE,
+				"Can't move fullscreen global container");
+	}
+
 	bool no_auto_back_and_forth = false;
 	while (strcasecmp(argv[0], "--no-auto-back-and-forth") == 0) {
 		no_auto_back_and_forth = true;
@@ -646,6 +651,10 @@ static struct cmd_results *cmd_move_workspace(int argc, char **argv) {
 	}
 
 	struct sway_workspace *workspace = config->handler_context.workspace;
+	if (!workspace) {
+		return cmd_results_new(CMD_FAILURE, "No workspace to move");
+	}
+
 	struct sway_output *old_output = workspace->output;
 	int center_x = workspace->width / 2 + workspace->x,
 		center_y = workspace->height / 2 + workspace->y;