app/dbus: Always call Reload() after transaction

Specifically in this case, this allows us to close a race condition
during `upgrade --check` where the `CachedUpdate` property might not
have been updated yet when we read it after finishing the transaction.

Closes: #1311
Approved by: cgwalters

src/app/rpmostree-dbus-helpers.c

@@ -689,6 +689,16 @@ rpmostree_transaction_connect_active (RPMOSTreeSysroot *sysroot_proxy,
   return FALSE;
 }
 
+static void
+on_reload_done (GObject      *src,
+                GAsyncResult *res,
+                gpointer      user_data)
+{
+  gboolean *donep = user_data;
+  *donep = TRUE;
+  (void) rpmostree_sysroot_call_reload_finish ((RPMOSTreeSysroot*)src, res, NULL);
+}
+
 /* Transactions need an explicit Start call so we can set up watches for signals
  * beforehand and avoid losing information.  We monitor the transaction,
  * printing output it sends, and handle Ctrl-C, etc.
@@ -784,6 +794,16 @@ rpmostree_transaction_get_response_sync (RPMOSTreeSysroot *sysroot_proxy,
         }
     }
 
+  /* On success, call Reload() as a way to sync with the daemon. Do this in async mode so
+   * that gdbus handles signals for changed properties. */
+  if (success)
+    {
+      gboolean done = FALSE;
+      rpmostree_sysroot_call_reload (sysroot_proxy, NULL, on_reload_done, &done);
+      while (!done)
+        g_main_context_iteration (NULL, TRUE);
+    }
+
 out:
   if (sigintid)
     g_source_remove (sigintid);

tests/vmcheck/test-autoupdate.sh

@@ -218,6 +218,9 @@ assert_output
 echo "ok check mode layered only with advisories"
 
 # check we see the same output with --check/--preview
+# clear out cache first to make sure they start from scratch
+vm_rpmostree cleanup -m
+vm_cmd systemctl stop rpm-ostreed
 vm_rpmostree upgrade --check > out.txt
 vm_rpmostree upgrade --preview > out-verbose.txt
 assert_output