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, 43 insertions, 7 deletions

diff --git a/sway/input/seat.c b/sway/input/seat.c
index bdab8b81..ce009d7e 100644
--- a/sway/input/seat.c
+++ b/sway/input/seat.c
@@ -172,14 +172,14 @@ static void handle_seat_node_destroy(struct wl_listener *listener, void *data) {
 
         seat_node_destroy(seat_node);
 
-        if (!parent) {
+        if (!parent && !needs_new_focus) {
                 // Destroying a container that is no longer in the tree
                 return;
         }
 
         // Find new focus_inactive (ie. sibling, or workspace if no siblings left)
         struct sway_node *next_focus = NULL;
-        while (next_focus == NULL) {
+        while (next_focus == NULL && parent != NULL) {
                 struct sway_container *con =
                         seat_get_focus_inactive_view(seat, parent);
                 next_focus = con ? &con->node : NULL;
@@ -192,6 +192,16 @@ static void handle_seat_node_destroy(struct wl_listener *listener, void *data) {
                 parent = node_get_parent(parent);
         }
 
+        if (!next_focus) {
+                struct sway_workspace *ws = seat_get_last_known_workspace(seat);
+                if (!ws) {
+                        return;
+                }
+                struct sway_container *con =
+                        seat_get_focus_inactive_view(seat, &ws->node);
+                next_focus = con ? &(con->node) : &(ws->node);
+        }
+
         if (next_focus->type == N_WORKSPACE &&
                         !workspace_is_visible(next_focus->sway_workspace)) {
                 // Do not change focus to a non-visible workspace
@@ -199,6 +209,10 @@ static void handle_seat_node_destroy(struct wl_listener *listener, void *data) {
         }
 
         if (needs_new_focus) {
+                // Make sure the workspace IPC event gets sent
+                if (node->type == N_CONTAINER && node->sway_container->scratchpad) {
+                        seat_set_focus(seat, NULL);
+                }
                 // The structure change might have caused it to move up to the top of
                 // the focus stack without sending focus notifications to the view
                 seat_send_focus(next_focus, seat);
@@ -207,7 +221,7 @@ static void handle_seat_node_destroy(struct wl_listener *listener, void *data) {
                 // Setting focus_inactive
                 focus = seat_get_focus_inactive(seat, &root->node);
                 seat_set_raw_focus(seat, next_focus);
-                if (focus->type == N_CONTAINER) {
+                if (focus->type == N_CONTAINER && focus->sway_container->workspace) {
                         seat_set_raw_focus(seat, &focus->sway_container->workspace->node);
                 }
                 seat_set_raw_focus(seat, focus);
@@ -795,7 +809,13 @@ void seat_set_raw_focus(struct sway_seat *seat, struct sway_node *node) {
         wl_list_remove(&seat_node->link);
         wl_list_insert(&seat->focus_stack, &seat_node->link);
         node_set_dirty(node);
-        node_set_dirty(node_get_parent(node));
+
+        // If focusing a scratchpad container that is fullscreen global, parent
+        // will be NULL
+        struct sway_node *parent = node_get_parent(node);
+        if (parent) {
+                node_set_dirty(parent);
+        }
 }
 
 void seat_set_focus(struct sway_seat *seat, struct sway_node *node) {
@@ -850,7 +870,8 @@ void seat_set_focus(struct sway_seat *seat, struct sway_node *node) {
                 }
         }
 
-        struct sway_output *new_output = new_workspace->output;
+        struct sway_output *new_output =
+                new_workspace ? new_workspace->output : NULL;
 
         if (last_workspace != new_workspace && new_output) {
                 node_set_dirty(&new_output->node);
@@ -894,7 +915,8 @@ void seat_set_focus(struct sway_seat *seat, struct sway_node *node) {
         }
 
         // Move sticky containers to new workspace
-        if (new_output_last_ws && new_workspace != new_output_last_ws) {
+        if (new_workspace && new_output_last_ws
+                        && new_workspace != new_output_last_ws) {
                 for (int i = 0; i < new_output_last_ws->floating->length; ++i) {
                         struct sway_container *floater =
                                 new_output_last_ws->floating->items[i];
@@ -940,7 +962,7 @@ void seat_set_focus(struct sway_seat *seat, struct sway_node *node) {
 
         seat->has_focus = true;
 
-        if (config->smart_gaps) {
+        if (config->smart_gaps && new_workspace) {
                 // When smart gaps is on, gaps may change when the focus changes so
                 // the workspace needs to be arranged
                 arrange_workspace(new_workspace);
@@ -1134,6 +1156,20 @@ struct sway_workspace *seat_get_focused_workspace(struct sway_seat *seat) {
         return NULL; // output doesn't have a workspace yet
 }
 
+struct sway_workspace *seat_get_last_known_workspace(struct sway_seat *seat) {
+        struct sway_seat_node *current;
+        wl_list_for_each(current, &seat->focus_stack, link) {
+                struct sway_node *node = current->node;
+                if (node->type == N_CONTAINER &&
+                                node->sway_container->workspace) {
+                        return node->sway_container->workspace;
+                } else if (node->type == N_WORKSPACE) {
+                        return node->sway_workspace;
+                }
+        }
+        return NULL;
+}
+
 struct sway_container *seat_get_focused_container(struct sway_seat *seat) {
         struct sway_node *focus = seat_get_focus(seat);
         if (focus && focus->type == N_CONTAINER) {