depot/third_party/nixpkgs/pkgs/development/libraries/glib/glib-appinfo-watch.patch

diff --git a/gio/gdesktopappinfo.c b/gio/gdesktopappinfo.c
index 87db7a97a..2e1689ed7 100644
--- a/gio/gdesktopappinfo.c
+++ b/gio/gdesktopappinfo.c
@@ -147,6 +147,7 @@ typedef struct
   gchar                      *alternatively_watching;
   gboolean                    is_config;
   gboolean                    is_setup;
+  gchar                      *nix_profile_watch_dir;
   GFileMonitor               *monitor;
   GHashTable                 *app_names;
   GHashTable                 *mime_tweaks;
@@ -179,6 +180,7 @@ desktop_file_dir_unref (DesktopFileDir *dir)
     {
       desktop_file_dir_reset (dir);
       g_free (dir->path);
+      g_free (dir->nix_profile_watch_dir);
       g_free (dir);
     }
 }
@@ -203,6 +205,14 @@ desktop_file_dir_get_alternative_dir (DesktopFileDir *dir)
 {
   gchar *parent;
 
+  /* If DIR is a profile, watch the specified directory--e.g.,
+   * /nix/var/nix/profiles/per-user/$USER/ for the user profile.  Do not watch
+   * ~/.nix-profile or /run/current-system/sw because GFileMonitor does
+   * not pass IN_DONT_FOLLOW and thus cannot notice any change.
+   * /etc/profiles/per-user is monitored directly for the same reason. */
+  if (dir->nix_profile_watch_dir != NULL)
+    return g_strdup (dir->nix_profile_watch_dir);
+
   /* If the directory itself exists then we need no alternative. */
   if (g_access (dir->path, R_OK | X_OK) == 0)
     return NULL;
@@ -248,11 +258,11 @@ desktop_file_dir_changed (GFileMonitor      *monitor,
    *
    * If this is a notification for a parent directory (because the
    * desktop directory didn't exist) then we shouldn't fire the signal
-   * unless something actually changed.
+   * unless something actually changed or it's part of a Nix profile.
    */
   g_mutex_lock (&desktop_file_dir_lock);
 
-  if (dir->alternatively_watching)
+  if (dir->alternatively_watching && dir->nix_profile_watch_dir == NULL)
     {
       gchar *alternative_dir;
 
@@ -1650,6 +1660,40 @@ desktop_file_dirs_lock (void)
       for (i = 0; dirs[i]; i++)
         g_ptr_array_add (desktop_file_dirs, desktop_file_dir_new (dirs[i]));
 
+      {
+        /* Monitor the system and user profile under /nix/var/nix/profiles and
+         * treat modifications to them as if they were modifications to their
+         * /share sub-directory.  */
+        const gchar *user;
+        DesktopFileDir *system_profile_dir, *user_profile_dir, *user_env_dir;
+
+        system_profile_dir =
+          desktop_file_dir_new ("/nix/var/nix/profiles/system/sw/share");
+        system_profile_dir->nix_profile_watch_dir = g_strdup ("/nix/var/nix/profiles");
+        g_ptr_array_add (desktop_file_dirs, desktop_file_dir_ref (system_profile_dir));
+
+        user = g_get_user_name ();
+        if (user != NULL)
+          {
+            gchar *profile_dir, *user_data_dir, *env_dir, *env_data_dir;
+
+            profile_dir = g_build_filename ("/nix/var/nix/profiles/per-user", user, NULL);
+            user_data_dir = g_build_filename (profile_dir, "profile", "share", NULL);
+            user_profile_dir = desktop_file_dir_new (user_data_dir);
+            user_profile_dir->nix_profile_watch_dir = profile_dir;
+
+            env_dir = g_build_filename ("/etc/profiles/per-user", NULL);
+            env_data_dir = g_build_filename (env_dir, user, "share", NULL);
+            user_env_dir = desktop_file_dir_new (env_data_dir);
+            user_env_dir->nix_profile_watch_dir = env_dir;
+
+            g_ptr_array_add (desktop_file_dirs, desktop_file_dir_ref (user_profile_dir));
+            g_ptr_array_add (desktop_file_dirs, desktop_file_dir_ref (user_env_dir));
+            g_free (user_data_dir);
+            g_free (env_data_dir);
+          }
+      }
+
       /* The list of directories will never change after this, unless
        * g_get_user_config_dir() changes due to %G_TEST_OPTION_ISOLATE_DIRS. */
       desktop_file_dirs_config_dir = user_config_dir;