apprt/gtk-ng: fix config textbuffer memory leak

src/apprt/gtk-ng.zig

@@ -6,10 +6,7 @@ pub const Surface = @import("gtk-ng/Surface.zig");
 pub const resourcesDir = internal_os.resourcesDir;
 
 // The exported API, custom for the apprt.
-pub const Application = @import("gtk-ng/class/application.zig").Application;
-pub const Window = @import("gtk-ng/class/window.zig").Window;
-pub const Config = @import("gtk-ng/class/config.zig").Config;
-
+pub const class = @import("gtk-ng/class.zig");
 pub const WeakRef = @import("gtk-ng/weak_ref.zig").WeakRef;
 
 test {

src/apprt/gtk-ng/class.zig

@@ -0,0 +1,26 @@
+//! This files contains all the GObject classes for the GTK apprt
+//! along with helpers to work with them.
+
+const glib = @import("glib");
+const gobject = @import("gobject");
+
+pub const Application = @import("class/application.zig").Application;
+pub const Window = @import("class/window.zig").Window;
+pub const Config = @import("class/config.zig").Config;
+
+/// Unrefs the given GObject on the next event loop tick.
+///
+/// This works around an issue with zig-object where dynamically
+/// generated gobjects in property getters can't unref themselves
+/// normally: https://github.com/ianprime0509/zig-gobject/issues/108
+pub fn unrefLater(obj: anytype) void {
+    _ = glib.idleAdd((struct {
+        fn callback(data_: ?*anyopaque) callconv(.c) c_int {
+            const remove = @intFromBool(glib.SOURCE_REMOVE);
+            const data = data_ orelse return remove;
+            const object: *gobject.Object = @ptrCast(@alignCast(data));
+            object.unref();
+            return remove;
+        }
+    }).callback, obj.as(gobject.Object));
+}

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

@@ -585,8 +585,8 @@ pub const Application = extern struct {
             self.as(Parent),
         );
 
-        const win = Window.new(self);
-        gtk.Window.present(win.as(gtk.Window));
+        // const win = Window.new(self);
+        // gtk.Window.present(win.as(gtk.Window));
     }
 
     fn dispose(self: *Self) callconv(.C) void {

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

@@ -1,12 +1,15 @@
 const std = @import("std");
 const Allocator = std.mem.Allocator;
 const adw = @import("adw");
+const glib = @import("glib");
 const gobject = @import("gobject");
 const gtk = @import("gtk");
 
 const configpkg = @import("../../../config.zig");
 const CoreConfig = configpkg.Config;
 
+const unrefLater = @import("../class.zig").unrefLater;
+
 const log = std.log.scoped(.gtk_ghostty_config);
 
 /// Wraps a `Ghostty.Config` object in a GObject so it can be reference
@@ -125,6 +128,7 @@ pub const Config = extern struct {
             text_buf.insertAtCursor("\n", 1);
         }
 
+        unrefLater(text_buf); // See unrefLater docs for why this is needed
         return text_buf;
     }
 

valgrind.supp

@@ -140,6 +140,20 @@
    ...
 }
 
+{
+   pango font map to cairgo
+   Memcheck:Leak
+   match-leak-kinds: possible
+   fun:malloc
+   ...
+   fun:FcConfigValues
+   fun:FcConfigSubstituteWithPat
+   fun:FcConfigSubstitute
+   fun:pango_cairo_fc_font_map_fontset_key_substitute
+   fun:pango_fc_font_map_load_fontset
+   ...
+}
+
 {
    Adwaita Stylesheet Load
    Memcheck:Leak