Fix fullscreen focus bug and corresponding test flaw

As the workspace might be reached via recursion (e.g. moving from the edge
of a fullscreen split container), it's necessary to check for a fullscreen
container whenever a workspace is reached.

src/commands.c

@@ -1297,14 +1297,6 @@ void cmd_exec(I3_CMD, char *nosn, char *command) {
  *
  */
 void cmd_focus_direction(I3_CMD, char *direction) {
-    if (focused &&
-        focused->type != CT_WORKSPACE &&
-        focused->fullscreen_mode != CF_NONE) {
-        LOG("Cannot change focus while in fullscreen mode.\n");
-        ysuccess(false);
-        return;
-    }
-
     DLOG("direction = *%s*\n", direction);
 
     if (strcmp(direction, "left") == 0)
@@ -1331,14 +1323,6 @@ void cmd_focus_direction(I3_CMD, char *direction) {
  *
  */
 void cmd_focus_window_mode(I3_CMD, char *window_mode) {
-    if (focused &&
-        focused->type != CT_WORKSPACE &&
-        focused->fullscreen_mode != CF_NONE) {
-        LOG("Cannot change focus while in fullscreen mode.\n");
-        ysuccess(false);
-        return;
-    }
-
     DLOG("window_mode = %s\n", window_mode);
 
     Con *ws = con_get_workspace(focused);

src/tree.c

@@ -466,6 +466,11 @@ static bool _tree_next(Con *con, char way, orientation_t orientation, bool wrap)
     /* Stop recursing at workspaces after attempting to switch to next
      * workspace if possible. */
     if (con->type == CT_WORKSPACE) {
+        if (con_get_fullscreen_con(con, CF_GLOBAL) ||
+            con_get_fullscreen_con(con, CF_OUTPUT)) {
+            DLOG("Cannot change workspace while in fullscreen mode.\n");
+            return false;
+        }
         Output *current_output = get_output_containing(con->rect.x, con->rect.y);
         Output *next_output;
 

testcases/t/156-fullscreen-focus.t

@@ -18,7 +18,20 @@
 # the time of launching the new one. Also make sure that focusing containers
 # in other workspaces work even when there is a fullscreen container.
 #
-use i3test;
+use i3test i3_autostart => 0;
+
+# Screen setup looks like this:
+# +----+----+
+# | S1 | S2 |
+# +----+----+
+my $config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+
+fake-outputs 1024x768+0+0,1024x768+1024+0
+EOT
+
+my $pid = launch_with_config($config);
 
 my $i3 = i3(get_socket_path());
 
@@ -305,4 +318,6 @@ verify_move(2, 'prevented move to workspace by position');
 
 # TODO: Tests for "move to output" and "move workspace to output".
 
+exit_gracefully($pid);
+
 done_testing;