libnm: implement NMSettInfoProperty.direct_also_notify for notifying two properties

We will deprecate "connection.master" for "connection.controller". The
old property will become an alias for the new one. That means, when
setting the property we must emit notifications for both the old and the
new property.

Add "NMSettInfoProperty.direct_also_notify" for that. This is not fully
flexible, as it only works for direct properties (duh) and only allows
to specify one addtitional GParamSpec (of the same NMSetting). It is
however sufficient for our use.

src/libnm-core-impl/nm-setting.c

@@ -993,6 +993,10 @@ out_notify:
      *
      * Currently we never set that, also because we still support glib 2.40. */
     nm_assert(!NM_FLAGS_HAS(pspec->flags, 1 << 30 /* G_PARAM_EXPLICIT_NOTIFY */));
+
+    /* We only notify "direct_also_notify". The other property is automatically notified. */
+    nm_gobject_notify_together_by_pspec(object, property_info->direct_also_notify);
+
     return;
 
 out_fail:
@@ -1388,7 +1392,9 @@ _nm_setting_property_from_dbus_fcn_direct_mac_address(_NM_SETT_INFO_PROP_FROM_DB
 
     if (nm_strdup_reset_take(_nm_setting_get_private_field(setting, sett_info, property_info),
                              length > 0 ? nm_utils_hwaddr_ntoa(array, length) : NULL)) {
-        g_object_notify_by_pspec(G_OBJECT(setting), property_info->param_spec);
+        nm_gobject_notify_together_by_pspec(setting,
+                                            property_info->param_spec,
+                                            property_info->direct_also_notify);
     } else
         *out_is_modified = FALSE;
 
@@ -1692,7 +1698,9 @@ out_unchanged:
 
 out_notify:
     *out_is_modified = TRUE;
-    g_object_notify_by_pspec(G_OBJECT(setting), property_info->param_spec);
+    nm_gobject_notify_together_by_pspec(setting,
+                                        property_info->param_spec,
+                                        property_info->direct_also_notify);
     return TRUE;
 
 out_error_wrong_dbus_type:

src/libnm-core-impl/tests/test-setting.c

@@ -4749,6 +4749,24 @@ test_setting_metadata(void)
             if (!can_have_direct_set_fcn)
                 g_assert(!sip->direct_set_fcn.set_string);
 
+            if (sip->property_type->direct_type == NM_VALUE_TYPE_NONE)
+                g_assert(!sip->direct_also_notify);
+            else {
+                if (sip->direct_also_notify) {
+                    guint prop_idx2;
+                    guint cnt = 0;
+
+                    for (prop_idx2 = 0; prop_idx2 < sis->property_infos_len; prop_idx2++) {
+                        const NMSettInfoProperty *sip2 = &sis->property_infos[prop_idx2];
+
+                        if (sip2->param_spec == sip->direct_also_notify)
+                            cnt++;
+                    }
+                    g_assert_cmpint(cnt, ==, 1u);
+                    g_assert(sip->param_spec != sip->direct_also_notify);
+                }
+            }
+
             n_special_options = (sip->direct_set_string_mac_address_len != 0)
                                 + (!!sip->direct_set_string_strip)
                                 + (!!sip->direct_set_string_ascii_strdown)

src/libnm-core-intern/nm-core-internal.h

@@ -784,6 +784,10 @@ struct _NMSettInfoProperty {
                                const char               *src);
     } direct_set_fcn;
 
+    /* For direct properties, this is the param_spec that also should be
+     * notified on changes. */
+    GParamSpec *direct_also_notify;
+
     /* This only has meaning for direct properties (property_type->direct_type != NM_VALUE_TYPE_UNSPEC).
      * In that case, this is the offset where _nm_setting_get_private() can find
      * the direct location. */