Fix use-after-free by moving config-reload into the manage cycle

src/Context.zig

@@ -21,6 +21,13 @@ xkb_bindings: *XkbBindings,
 // WM Configuration
 config: *Config,
 
+/// State consumed in manage() phase, reset at end of manage().
+pending_manage: PendingManage = .{},
+
+pub const PendingManage = struct {
+    config: ?*Config = null,
+};
+
 pub fn create(
     wl_display: *wl.Display,
     wl_registry: *wl.Registry,
@@ -52,6 +59,22 @@ pub fn destroy(context: *Context) void {
     utils.allocator.destroy(context);
 }
 
+pub fn manage(context: *Context) void {
+    defer context.pending_manage = .{};
+
+    if (context.pending_manage.config) |new_config| {
+        // Destroy all existing bindings
+        var it = context.xkb_bindings.bindings.safeIterator(.forward);
+        while (it.next()) |binding| {
+            binding.link.remove();
+            binding.destroy();
+        }
+        context.config.destroy();
+        context.config = new_config;
+        context.initialized = false;
+    }
+}
+
 const std = @import("std");
 
 const wayland = @import("wayland");

src/WindowManager.zig

@@ -186,9 +186,12 @@ fn manage_start(wm: *WindowManager) void {
 
     const river_window_manager_v1 = wm.river_window_manager_v1;
     const context = wm.context;
+
+    // This gets used shortly, so it goes at the beginning
+    context.manage();
+
     if (!context.initialized) {
-        // This code (should) only be run once while initializing the WM, so let's
-        // mark it as cold.
+        // This code runs during initial startup and after config reloads.
         @branchHint(.cold);
         context.initialized = true;
 
@@ -220,7 +223,7 @@ fn manage_start(wm: *WindowManager) void {
         }
     }
 
-    // Manage the WM itself first
+    // Manage the WM itself before outputs/windows/seats
     if (wm.pending_manage.primary_ratio) |primary_ratio| {
         // Ratios outside of this range can cause crashes anyways (when doing the layout calulcation)
         std.debug.assert(primary_ratio >= 0.10 and primary_ratio <= 0.90);

src/XkbBindings.zig

@@ -45,7 +45,7 @@ const XkbBinding = struct {
         return xkb_binding;
     }
 
-    fn destroy(xkb_binding: *XkbBinding) void {
+    pub fn destroy(xkb_binding: *XkbBinding) void {
         xkb_binding.xkb_binding_v1.destroy();
         utils.allocator.destroy(xkb_binding);
     }
@@ -137,16 +137,9 @@ const XkbBinding = struct {
                     log.err("Failed to reload Config. Not deleting old one", .{});
                     return;
                 };
-                // Clean up old one
-                var it = context.xkb_bindings.bindings.safeIterator(.forward);
-                while (it.next()) |binding| {
-                    binding.link.remove();
-                    binding.destroy();
-                }
-                context.config.destroy();
-                // Replace the old one
-                context.config = new_config;
-                context.initialized = false;
+                // Send the config to the WM to handle during next manage
+                context.pending_manage.config = new_config;
+                context.wm.river_window_manager_v1.manageDirty();
             },
             .toggle_fullscreen => {
                 const seat = context.wm.seats.first() orelse return;