refactor: do not use and deprecate setDefaultController() method

The constructor of the Router class already defines the default controller.

system/Router/Router.php

@@ -459,15 +459,12 @@ public function autoRoute(string $uri)
  {
  $segments = explode('/', $uri);
 
+ // WARNING: Directories get shifted out of the segments array.
  $segments = $this->scanControllers($segments);
 
- // If we don't have any segments left - try the default controller;
- // WARNING: Directories get shifted out of the segments array.
- if (empty($segments)) {
- $this->setDefaultController();
- }
+ // If we don't have any segments left - use the default controller;
  // If not empty, then the first segment should be the controller
- else {
+ if (! empty($segments)) {
  $this->controller = ucfirst(array_shift($segments));
  }
 
@@ -643,8 +640,6 @@ protected function setRequest(array $segments = [])
  {
  // If we don't have any segments - try the default controller;
  if (empty($segments)) {
- $this->setDefaultController();
-
  return;
  }
 
@@ -665,6 +660,8 @@ protected function setRequest(array $segments = [])
 
  /**
  * Sets the default controller based on the info set in the RouteCollection.
+ *
+ * @deprecated This was an unnecessary method, so it is no longer used.
  */
  protected function setDefaultController()
  {

user_guide_src/source/changelogs/v4.2.0.rst

@@ -42,6 +42,7 @@ Deprecations
 - ``CodeIgniter\Database\SQLSRV\Connection::getError()`` is deprecated. Use ``CodeIgniter\Database\SQLSRV\Connection::error()`` instead.
 - ``CodeIgniter\Debug\Exceptions::cleanPath()`` and ``CodeIgniter\Debug\Toolbar\Collectors\BaseCollector::cleanPath()`` are deprecated. Use the ``clean_path()`` function instead.
 - ``CodeIgniter\Log\Logger::cleanFilenames()`` and ``CodeIgniter\Test\TestLogger::cleanup()`` are both deprecated. Use the ``clean_path()`` function instead.
+- ``CodeIgniter\Router\setDefaultController()`` is deprecated.
 
 Bugs Fixed
 **********