[mutter] tests/test-client: Wait for processs to exit before shutting down

[Marge Bot <marge-bot src gnome org>]

commit 9988dc344d7f49282580fd41e1d2a3c30568d056
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Aug 5 16:05:32 2022 +0200

    tests/test-client: Wait for processs to exit before shutting down
    
    This makes sure the client has exited cleanly before the Wayland server
    is teared down, causing the client to potentially end up with a broken
    pipe.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2561>

 src/tests/meta-test-utils.c | 73 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)
---
diff --git a/src/tests/meta-test-utils.c b/src/tests/meta-test-utils.c
index 626317b466..a4980ef93e 100644
--- a/src/tests/meta-test-utils.c
+++ b/src/tests/meta-test-utils.c
@@ -62,6 +62,11 @@ struct _MetaAsyncWaiter
   int counter_wait_value;
 };
 
+typedef struct
+{
+  GList *subprocesses;
+} ClientProcessHandler;
+
 G_DEFINE_QUARK (meta-test-client-error-quark, meta_test_client_error)
 
 static char *test_client_path;
@@ -478,6 +483,66 @@ spawn_xwayland (gpointer user_data)
   return NULL;
 }
 
+static void
+on_prepare_shutdown (MetaBackend          *backend,
+                     ClientProcessHandler *process_handler)
+{
+  g_debug ("Waiting for test clients to exit before shutting down");
+  while (process_handler->subprocesses)
+    g_main_context_iteration (NULL, TRUE);
+}
+
+static void
+wait_check_cb (GObject      *source_object,
+               GAsyncResult *result,
+               gpointer      user_data)
+{
+  GSubprocess *subprocess = G_SUBPROCESS (source_object);
+  ClientProcessHandler *process_handler = user_data;
+  g_autoptr (GError) error = NULL;
+
+  if (!g_subprocess_wait_check_finish (subprocess, result, &error))
+    {
+      if (g_error_matches (error, G_SPAWN_EXIT_ERROR, 1))
+        {
+          g_debug ("Test client process %s exited with exit status 1",
+                   g_subprocess_get_identifier (subprocess));
+        }
+      else
+        {
+          g_warning ("Test client process %s crashed with status %d",
+                     g_subprocess_get_identifier (subprocess),
+                     error->code);
+        }
+    }
+
+  process_handler->subprocesses = g_list_remove (process_handler->subprocesses,
+                                                 subprocess);
+}
+
+static ClientProcessHandler *
+ensure_process_handler (MetaContext *context)
+{
+  ClientProcessHandler *process_handler;
+  const char data_key[] = "test-client-subprocess-handler";
+  MetaBackend *backend;
+
+  process_handler = g_object_get_data (G_OBJECT (context), data_key);
+  if (process_handler)
+    return process_handler;
+
+  process_handler = g_new0 (ClientProcessHandler, 1);
+  g_object_set_data_full (G_OBJECT (context), data_key,
+                          process_handler, g_free);
+
+  backend = meta_context_get_backend (context);
+  g_signal_connect (backend, "prepare-shutdown",
+                    G_CALLBACK (on_prepare_shutdown),
+                    process_handler);
+
+  return process_handler;
+}
+
 MetaTestClient *
 meta_test_client_new (MetaContext           *context,
                       const char            *id,
@@ -487,6 +552,7 @@ meta_test_client_new (MetaContext           *context,
   MetaTestClient *client;
   GSubprocessLauncher *launcher;
   GSubprocess *subprocess;
+  ClientProcessHandler *process_handler;
   MetaWaylandCompositor *compositor;
   const char *wayland_display_name;
   const char *x11_display_name;
@@ -526,6 +592,13 @@ meta_test_client_new (MetaContext           *context,
   if (!subprocess)
     return NULL;
 
+  process_handler = ensure_process_handler (context);
+  process_handler->subprocesses = g_list_prepend (process_handler->subprocesses,
+                                                  subprocess);
+  g_subprocess_wait_check_async (subprocess, NULL,
+                                 wait_check_cb,
+                                 process_handler);
+
   client = g_new0 (MetaTestClient, 1);
   client->type = type;
   client->id = g_strdup (id);