This patch lets GLib's GDesktopAppInfo API watch and notice changes
to the Guix user and system profiles.  That way, the list of available
applications shown by the desktop environment is immediately updated
when the user runs "guix install", "guix remove", or "guix system
reconfigure" (see <https://issues.guix.gnu.org/35594>).

It does so by monitoring /var/guix/profiles (for changes to the system
profile) and /var/guix/profiles/per-user/USER (for changes to the user
profile) and crawling their share/applications sub-directory when
changes happen.

diff --git a/gio/gdesktopappinfo.c b/gio/gdesktopappinfo.c
index f1e2fdd..095c110 100644
--- a/gio/gdesktopappinfo.c
+++ b/gio/gdesktopappinfo.c
@@ -148,6 +148,7 @@ typedef struct
   gchar                      *alternatively_watching;
   gboolean                    is_config;
   gboolean                    is_setup;
+  gchar                      *guix_profile_watch_dir;
   GFileMonitor               *monitor;
   GHashTable                 *app_names;
   GHashTable                 *mime_tweaks;
@@ -180,6 +181,7 @@ desktop_file_dir_unref (DesktopFileDir *dir)
     {
       desktop_file_dir_reset (dir);
       g_free (dir->path);
+      g_free (dir->guix_profile_watch_dir);
       g_free (dir);
     }
 }
@@ -204,6 +206,13 @@ desktop_file_dir_get_alternative_dir (DesktopFileDir *dir)
 {
   gchar *parent;
 
+  /* If DIR is a profile, watch the specified directory--e.g.,
+   * /var/guix/profiles/per-user/$USER/ for the user profile.  Do not watch
+   * ~/.guix-profile or /run/current-system/profile because GFileMonitor does
+   * not pass IN_DONT_FOLLOW and thus cannot notice any change.  */
+  if (dir->guix_profile_watch_dir != NULL)
+    return g_strdup (dir->guix_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;
@@ -249,11 +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 in /var/guix/profiles.
    */
   g_mutex_lock (&desktop_file_dir_lock);
 
-  if (dir->alternatively_watching)
+  if (dir->alternatively_watching && dir->guix_profile_watch_dir == NULL)
     {
       gchar *alternative_dir;
 
@@ -1555,6 +1564,32 @@ 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 /var/guix/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;
+
+        system_profile_dir =
+          desktop_file_dir_new ("/var/guix/profiles/system/profile/share");
+        system_profile_dir->guix_profile_watch_dir = g_strdup ("/var/guix/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;
+
+            profile_dir = g_build_filename ("/var/guix/profiles/per-user", user, NULL);
+            user_data_dir = g_build_filename (profile_dir, "guix-profile", "share", NULL);
+            user_profile_dir = desktop_file_dir_new (user_data_dir);
+            user_profile_dir->guix_profile_watch_dir = profile_dir;
+            g_ptr_array_add (desktop_file_dirs, desktop_file_dir_ref (user_profile_dir));
+            g_free (user_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;
rdinator-agent command.

Change-Id: Ide6dde0e88aa0dc851b6295095f414ca2ddc72ac
Reviewed-by: Maxim Cournoyer &lt;maxim.cournoyer@gmail&gt;
</span></span></td><td>Andreas Enge</td></tr>
<tr><td><span title='2024-06-06 17:53:49 +0100'>2024-06-06</span></td><td><a href='/guix/commit/gnu/services/guix.scm?id=1da1b42cace1bfd249f5360c308b0694dc50ce9a'>services: guix-build-coordinator: Don't log with timestamps.</a><span class='msg-avail'>...<span class='msg-tooltip'>As the shepherd adds these to the logs.

* gnu/services/guix.scm (make-guix-build-coordinator-start-script): Pass
 #:timestamp-log-output? #f to make-build-coordinator.
(guix-build-coordinator-agent-shepherd-services): Add
--timestamp-log-output=false to the arguments.

Change-Id: I9073ee7b1cefa894d38fdf3831c59de693e087f6
</span></span></td><td>Christopher Baines</td></tr>
<tr><td><span title='2024-06-02 15:06:16 +0400'>2024-06-02</span></td><td><a href='/guix/commit/gnu/services/guix.scm?id=eac5171246da875f5996621c5329c833fd85b891'>Revert "services: home: Use pairs instead of lists."</a><span class='msg-avail'>...<span class='msg-tooltip'>This reverts commit dbeef44f3c520816251bde74c1005915a637e1ef.

Despite the more semantically correct data type, it doesn't follow the style
of the most services and also breaks user-facing API.

Change-Id: Ib4ef4e9cd2f53ac853a5b7c7c90e57c35c99a5ea
</span></span></td><td>Andrew Tropin</td></tr>
<tr><td><span title='2024-06-02 13:38:52 +0400'>2024-06-02</span></td><td><a href='/guix/commit/gnu/services/guix.scm?id=dbeef44f3c520816251bde74c1005915a637e1ef'>services: home: Use pairs instead of lists.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/guix.scm: Use pairs instead of lists.
* doc/guix.texi: Update accordingly.
* gnu/tests/guix.scm: Update accordingly.

Change-Id: I0b8d3fa5b214add89bdb84a11fa20d1b319435f0
</span></span></td><td>Andrew Tropin</td></tr>