apprt/gtk-ng: clean up some changed handlers

src/apprt/gtk-ng/class/split_tree.zig

@@ -330,9 +330,18 @@ pub const SplitTree = extern struct {
 
     /// Set the tree data model that we're showing in this widget. This
     /// will clone the given tree.
-    pub fn setTree(self: *Self, tree: ?*const Surface.Tree) void {
+    pub fn setTree(self: *Self, tree_: ?*const Surface.Tree) void {
         const priv = self.private();
 
+        // We always normalize our tree parameter so that empty trees
+        // become null so that we don't have to deal with callers being
+        // confused about that.
+        const tree: ?*const Surface.Tree = tree: {
+            const tree = tree_ orelse break :tree null;
+            if (tree.isEmpty()) break :tree null;
+            break :tree tree;
+        };
+
         // Emit the signal so that handlers can witness both the before and
         // after values of the tree.
         signals.changed.impl.emit(
@@ -349,6 +358,8 @@ pub const SplitTree = extern struct {
         }
 
         if (tree) |new_tree| {
+            assert(priv.tree == null);
+            assert(!new_tree.isEmpty());
             priv.tree = ext.boxedCopy(Surface.Tree, new_tree);
             self.connectSurfaceHandlers();
         }

src/apprt/gtk-ng/class/tab.zig

@@ -242,14 +242,15 @@ pub const Tab = extern struct {
     //---------------------------------------------------------------
     // Signal handlers
 
-    fn splitTreeChanged(
+    fn propSplitTree(
         _: *SplitTree,
-        _: ?*const Surface.Tree,
-        new_tree: ?*const Surface.Tree,
+        _: *gobject.ParamSpec,
         self: *Self,
     ) callconv(.c) void {
+        self.as(gobject.Object).notifyByPspec(properties.@"surface-tree".impl.param_spec);
+
         // If our tree is empty we close the tab.
-        const tree: *const Surface.Tree = new_tree orelse &.empty;
+        const tree: *const Surface.Tree = self.getSurfaceTree() orelse &.empty;
         if (tree.isEmpty()) {
             signals.@"close-request".impl.emit(
                 self,
@@ -261,14 +262,6 @@ pub const Tab = extern struct {
         }
     }
 
-    fn propSplitTree(
-        _: *SplitTree,
-        _: *gobject.ParamSpec,
-        self: *Self,
-    ) callconv(.c) void {
-        self.as(gobject.Object).notifyByPspec(properties.@"surface-tree".impl.param_spec);
-    }
-
     fn propActiveSurface(
         _: *SplitTree,
         _: *gobject.ParamSpec,
@@ -318,7 +311,6 @@ pub const Tab = extern struct {
             class.bindTemplateChildPrivate("split_tree", .{});
 
             // Template Callbacks
-            class.bindTemplateCallback("tree_changed", &splitTreeChanged);
             class.bindTemplateCallback("notify_active_surface", &propActiveSurface);
             class.bindTemplateCallback("notify_tree", &propSplitTree);
 

src/apprt/gtk-ng/ui/1.5/tab.blp

@@ -12,6 +12,5 @@ template $GhosttyTab: Box {
   $GhosttySplitTree split_tree {
     notify::active-surface => $notify_active_surface();
     notify::tree => $notify_tree();
-    changed => $tree_changed();
   }
 }

src/datastruct/split_tree.zig

@@ -826,8 +826,10 @@ pub fn SplitTree(comptime V: type) type {
                         .copy = &struct {
                             fn copy(self: *Self) callconv(.c) *Self {
                                 const ptr = @import("glib").ext.create(Self);
-                                const alloc = self.arena.child_allocator;
-                                ptr.* = self.clone(alloc) catch @panic("oom");
+                                ptr.* = if (self.nodes.len == 0)
+                                    .empty
+                                else
+                                    self.clone(self.arena.child_allocator) catch @panic("oom");
                                 return ptr;
                             }
                         }.copy,