Bugfix: Close containers which are empty due to a move (Thanks fernando)

include/con.h

@@ -75,6 +75,12 @@ Con *con_by_frame_id(xcb_window_t frame);
  */
 Con *con_for_window(i3Window *window, Match **store_match);
 
+/**
+ * Returns the number of children of this container.
+ *
+ */
+int con_num_children(Con *con);
+
 /**
  * Attaches the given container to the given parent. This happens when moving
  * a container or when inserting a new container at a specific place in the

src/con.c

@@ -286,6 +286,20 @@ Con *con_for_window(i3Window *window, Match **store_match) {
     return NULL;
 }
 
+/*
+ * Returns the number of children of this container.
+ *
+ */
+int con_num_children(Con *con) {
+    Con *child;
+    int children = 0;
+
+    TAILQ_FOREACH(child, &(con->nodes_head), nodes)
+        children++;
+
+    return children;
+}
+
 /*
  * Updates the percent attribute of the children of the given container. This
  * function needs to be called when a window is added or removed from a
@@ -294,9 +308,7 @@ Con *con_for_window(i3Window *window, Match **store_match) {
  */
 void con_fix_percent(Con *con, int action) {
     Con *child;
-    int children = 0;
-    TAILQ_FOREACH(child, &(con->nodes_head), nodes)
-        children++;
+    int children = con_num_children(con);
     /* TODO: better document why this math works */
     double fix;
     if (action == WINDOW_ADD)
@@ -446,4 +458,6 @@ Rect con_border_style_rect(Con *con) {
 
     if (con->border_style == BS_NONE)
         return (Rect){0, 0, 0, 0};
+
+    assert(false);
 }

src/render.c

@@ -19,10 +19,7 @@ static bool show_debug_borders = false;
 void render_con(Con *con) {
     printf("currently rendering node %p / %s / layout %d\n",
             con, con->name, con->layout);
-    int children = 0;
-    Con *child;
-    TAILQ_FOREACH(child, &(con->nodes_head), nodes)
-        children++;
+    int children = con_num_children(con);
     printf("children: %d, orientation = %d\n", children, con->orientation);
 
     /* Copy container rect, subtract container border */
@@ -103,6 +100,7 @@ void render_con(Con *con) {
         return;
     }
 
+    Con *child;
     TAILQ_FOREACH(child, &(con->nodes_head), nodes) {
 
         /* default layout */

src/tree.c

@@ -364,6 +364,7 @@ void tree_next(char way, orientation_t orientation) {
 void tree_move(char way, orientation_t orientation) {
     /* 1: get the first parent with the same orientation */
     Con *parent = focused->parent;
+    Con *old_parent = parent;
     if (focused->type == CT_WORKSPACE)
         return;
     bool level_changed = false;
@@ -431,4 +432,9 @@ void tree_move(char way, orientation_t orientation) {
         TAILQ_INSERT_HEAD(&(next->parent->focus_head), focused, focused);
         /* TODO: don’t influence focus handling? */
     }
+
+    if (con_num_children(old_parent) == 0) {
+        DLOG("Old container empty after moving. Let's close it\n");
+        tree_close(old_parent, false);
+    }
 }

testcases/t/24-move.t

@@ -7,7 +7,7 @@
 # 3) move a container inside another container
 # 4) move a container in a different direction so that we need to go up in tree
 #
-use i3test tests => 16;
+use i3test tests => 17;
 use X11::XCB qw(:all);
 
 my $i3 = i3("/tmp/nestedcons");
@@ -109,4 +109,20 @@ $i3->command('move after h')->recv;
 $content = get_ws_content($tmp);
 is(@{$content}, 2, 'two nodes on this workspace');
 
+######################################################################
+# 4) Move a container horizontally when inside a vertical split container.
+#    The container will be moved to the workspace level and the old vsplit
+#    container needs to be closed. Verify that it will be closed.
+######################################################################
+
+my $otmp = get_unused_workspace();
+$i3->command("workspace $otmp")->recv;
+
+$i3->command("open")->recv;
+$i3->command("split v")->recv;
+$i3->command("move after h")->recv;
+
+$content = get_ws_content($otmp);
+is(@{$content}, 1, 'only one nodes on this workspace');
+
 diag( "Testing i3, Perl $], $^X" );