[gnome-software/1405-rpm-ostree-don-t-show-transaction-in-progress-error: 2/2] rpm-ostree: Wait for an ongoing transaction end before running new transaction

[Milan Crha <mcrha src gnome org>]

commit dacde32afd1584b30a7ab31e9573f8e02e6647a0
Author: Milan Crha <mcrha redhat com>
Date:   Mon Sep 20 19:19:55 2021 +0200

    rpm-ostree: Wait for an ongoing transaction end before running new transaction
    
    The rpm-ostree cannot schedule transactions, thus in case there's
    any ongoing transaction (maybe not run by the Software), wait for
    it to be finished. It's a workaround suggested at:
    https://github.com/coreos/rpm-ostree/issues/3070
    
    Closes https://gitlab.gnome.org/GNOME/gnome-software/-/issues/1405

 plugins/rpm-ostree/gs-plugin-rpm-ostree.c | 74 +++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)
---
diff --git a/plugins/rpm-ostree/gs-plugin-rpm-ostree.c b/plugins/rpm-ostree/gs-plugin-rpm-ostree.c
index a87fba4bd..59b9f579c 100644
--- a/plugins/rpm-ostree/gs-plugin-rpm-ostree.c
+++ b/plugins/rpm-ostree/gs-plugin-rpm-ostree.c
@@ -552,6 +552,53 @@ out:
        return success;
 }
 
+/* FIXME: Refactor this once rpmostree returns a specific error code
+ * for ‘transaction in progress’, to avoid the slight race here where
+ * gnome-software could return from this function just as another client
+ * starts a new transaction.
+ * https://github.com/coreos/rpm-ostree/issues/3070 */
+static gboolean
+gs_rpmostree_wait_for_ongoing_transaction_end (GsRPMOSTreeSysroot *sysroot_proxy,
+                                              GCancellable *cancellable,
+                                              GError **error)
+{
+       g_autofree gchar *current_path = NULL;
+       g_autoptr(GMainContext) main_context = NULL;
+       gulong notify_handler, cancelled_handler = 0;
+
+       current_path = gs_rpmostree_sysroot_dup_active_transaction_path (sysroot_proxy);
+       if (current_path == NULL || *current_path == '\0')
+               return TRUE;
+
+       main_context = g_main_context_ref_thread_default ();
+
+       notify_handler = g_signal_connect_swapped (sysroot_proxy, "notify::active-transaction-path",
+                                                  G_CALLBACK (g_main_context_wakeup), main_context);
+       if (cancellable) {
+               /* Not using g_cancellable_connect() here for simplicity and because checking the state below 
anyway. */
+               cancelled_handler = g_signal_connect_swapped (cancellable, "cancelled",
+                                                             G_CALLBACK (g_main_context_wakeup), 
main_context);
+       }
+
+       while (!g_cancellable_set_error_if_cancelled (cancellable, error)) {
+               g_clear_pointer (&current_path, g_free);
+               current_path = gs_rpmostree_sysroot_dup_active_transaction_path (sysroot_proxy);
+               if (current_path == NULL || *current_path == '\0') {
+                       g_clear_signal_handler (&notify_handler, sysroot_proxy);
+                       g_clear_signal_handler (&cancelled_handler, cancellable);
+                       return TRUE;
+               }
+               g_main_context_iteration (main_context, TRUE);
+       }
+
+       g_clear_signal_handler (&notify_handler, sysroot_proxy);
+       g_clear_signal_handler (&cancelled_handler, cancellable);
+
+       gs_rpmostree_error_convert (error);
+
+       return FALSE;
+}
+
 static GsApp *
 app_from_modified_pkg_variant (GsPlugin *plugin, GVariant *variant)
 {
@@ -858,6 +905,9 @@ gs_plugin_refresh (GsPlugin *plugin,
                g_autoptr(GVariant) options = NULL;
                g_autoptr(TransactionProgress) tp = NULL;
 
+               if (!gs_rpmostree_wait_for_ongoing_transaction_end (sysroot_proxy, cancellable, error))
+                       return FALSE;
+
                progress_app = gs_app_new (gs_plugin_get_name (plugin));
                tp = transaction_progress_new ();
                tp->app = g_object_ref (progress_app);
@@ -892,6 +942,9 @@ gs_plugin_refresh (GsPlugin *plugin,
                g_autoptr(GVariant) options = NULL;
                g_autoptr(TransactionProgress) tp = transaction_progress_new ();
 
+               if (!gs_rpmostree_wait_for_ongoing_transaction_end (sysroot_proxy, cancellable, error))
+                       return FALSE;
+
                tp->app = g_object_ref (progress_app);
                tp->plugin = g_object_ref (plugin);
 
@@ -931,6 +984,9 @@ gs_plugin_refresh (GsPlugin *plugin,
                GVariantDict dict;
                g_autoptr(TransactionProgress) tp = transaction_progress_new ();
 
+               if (!gs_rpmostree_wait_for_ongoing_transaction_end (sysroot_proxy, cancellable, error))
+                       return FALSE;
+
                tp->app = g_object_ref (progress_app);
                tp->plugin = g_object_ref (plugin);
 
@@ -1106,6 +1162,9 @@ trigger_rpmostree_update (GsPlugin *plugin,
        if (priv->update_triggered)
                return TRUE;
 
+       if (!gs_rpmostree_wait_for_ongoing_transaction_end (sysroot_proxy, cancellable, error))
+               return FALSE;
+
        /* trigger the update */
        options = make_rpmostree_options_variant (FALSE,  /* reboot */
                                                  FALSE,  /* allow-downgrade */
@@ -1194,6 +1253,9 @@ gs_plugin_app_upgrade_trigger (GsPlugin *plugin,
        if (!gs_rpmostree_ref_proxies (plugin, &os_proxy, &sysroot_proxy, cancellable, error))
                return FALSE;
 
+       if (!gs_rpmostree_wait_for_ongoing_transaction_end (sysroot_proxy, cancellable, error))
+               return FALSE;
+
        /* construct new refspec based on the distro version we're upgrading to */
        new_refspec = g_strdup_printf ("ostree://fedora/%s/x86_64/silverblue",
                                       gs_app_get_version (app));
@@ -1254,6 +1316,9 @@ gs_rpmostree_repo_enable (GsPlugin *plugin,
        g_autoptr(GVariantBuilder) options_builder = NULL;
        g_autoptr(TransactionProgress) tp = NULL;
 
+       if (!gs_rpmostree_wait_for_ongoing_transaction_end (sysroot_proxy, cancellable, error))
+               return FALSE;
+
        if (enable)
                gs_app_set_state (app, GS_APP_STATE_INSTALLING);
        else
@@ -1355,6 +1420,9 @@ gs_plugin_app_install (GsPlugin *plugin,
                return FALSE;
        }
 
+       if (!gs_rpmostree_wait_for_ongoing_transaction_end (sysroot_proxy, cancellable, error))
+               return FALSE;
+
        gs_app_set_state (app, GS_APP_STATE_INSTALLING);
        tp->app = g_object_ref (app);
 
@@ -1425,6 +1493,9 @@ gs_plugin_app_remove (GsPlugin *plugin,
        /* disable repo, handled by dedicated function */
        g_return_val_if_fail (gs_app_get_kind (app) != AS_COMPONENT_KIND_REPOSITORY, FALSE);
 
+       if (!gs_rpmostree_wait_for_ongoing_transaction_end (sysroot_proxy, cancellable, error))
+               return FALSE;
+
        gs_app_set_state (app, GS_APP_STATE_REMOVING);
        tp->app = g_object_ref (app);
 
@@ -1823,6 +1894,9 @@ gs_plugin_app_upgrade_download (GsPlugin *plugin,
        if (!gs_rpmostree_ref_proxies (plugin, &os_proxy, &sysroot_proxy, cancellable, error))
                return FALSE;
 
+       if (!gs_rpmostree_wait_for_ongoing_transaction_end (sysroot_proxy, cancellable, error))
+               return FALSE;
+
        /* construct new refspec based on the distro version we're upgrading to */
        new_refspec = g_strdup_printf ("ostree://fedora/%s/x86_64/silverblue",
                                       gs_app_get_version (app));