gtask: Add g_task_return_new_error_literal()

Avoids going through the formatting function or nesting GError calls.

gio/gtask.c

@@ -2031,7 +2031,8 @@ g_task_propagate_boolean (GTask   *task,
  * Call g_error_copy() on the error if you need to keep a local copy
  * as well.
  *
- * See also g_task_return_new_error().
+ * See also [method@Gio.Task.return_new_error],
+ * [method@Gio.Task.return_new_error_literal].
  *
  * Since: 2.36
  */
@@ -2130,6 +2131,32 @@ g_task_return_new_error (GTask           *task,
   g_task_return_error (task, error);
 }
 
+/**
+ * g_task_return_new_error_literal:
+ * @task: a #GTask.
+ * @domain: a #GQuark.
+ * @code: an error code.
+ * @message: an error message
+ *
+ * Sets @task’s result to a new [type@GLib.Error] created from @domain, @code,
+ * @message and completes the task.
+ *
+ * See [method@Gio.Task.return_pointer] for more discussion of exactly what
+ * ‘completing the task’ means.
+ *
+ * See also [method@Gio.Task.return_new_error].
+ *
+ * Since: 2.80
+ */
+void
+g_task_return_new_error_literal (GTask      *task,
+                                 GQuark      domain,
+                                 gint        code,
+                                 const char *message)
+{
+  g_task_return_error (task, g_error_new_literal (domain, code, message));
+}
+
 /**
  * g_task_return_error_if_cancelled:
  * @task: a #GTask

gio/gtask.h

@@ -175,6 +175,12 @@ void          g_task_return_new_error          (GTask           *task,
                                                 gint             code,
                                                 const char      *format,
                                                 ...) G_GNUC_PRINTF (4, 5);
+
+GIO_AVAILABLE_IN_2_80
+void          g_task_return_new_error_literal  (GTask           *task,
+                                                GQuark           domain,
+                                                gint             code,
+                                                const char      *message);
 GIO_AVAILABLE_IN_2_64
 void          g_task_return_value              (GTask           *task,
                                                 GValue          *result);

gio/tests/task.c

@@ -213,6 +213,53 @@ test_error (void)
   g_free (result.expected_message);
 }
 
+static void
+test_error_literal (void)
+{
+  GTask *task;
+  TaskErrorResult result;
+
+  task = g_task_new (NULL, NULL, error_callback, &result);
+  result = (TaskErrorResult){
+    .expected_domain = G_IO_ERROR,
+    .expected_code = G_IO_ERROR_FAILED,
+    .expected_message = "Literal Failure",
+  };
+
+  g_task_return_new_error_literal (task,
+                                   result.expected_domain,
+                                   result.expected_code,
+                                   "Literal Failure");
+
+  wait_for_completed_notification (task);
+  g_assert_cmpint (result.int_result, ==, -1);
+
+  g_assert_finalize_object (task);
+}
+
+static void
+test_error_literal_from_variable (void)
+{
+  GTask *task;
+  TaskErrorResult result;
+
+  task = g_task_new (NULL, NULL, error_callback, &result);
+  result = (TaskErrorResult){
+    .expected_domain = G_IO_ERROR,
+    .expected_code = G_IO_ERROR_FAILED,
+    .expected_message = "Literal Failure",
+  };
+
+  g_task_return_new_error_literal (task,
+                                   result.expected_domain,
+                                   result.expected_code,
+                                   result.expected_message);
+
+  wait_for_completed_notification (task);
+  g_assert_cmpint (result.int_result, ==, -1);
+  g_assert_finalize_object (task);
+}
+
 /* test_return_from_same_iteration: calling g_task_return_* from the
  * loop iteration the task was created in defers completion until the
  * next iteration.
@@ -2532,6 +2579,8 @@ main (int argc, char **argv)
 
   g_test_add_func ("/gtask/basic", test_basic);
   g_test_add_func ("/gtask/error", test_error);
+  g_test_add_func ("/gtask/error-literal", test_error_literal);
+  g_test_add_func ("/gtask/error-literal-from-variable", test_error_literal_from_variable);
   g_test_add_func ("/gtask/return-from-same-iteration", test_return_from_same_iteration);
   g_test_add_func ("/gtask/return-from-toplevel", test_return_from_toplevel);
   g_test_add_func ("/gtask/return-from-anon-thread", test_return_from_anon_thread);