[5.1] Use update channel the correct way

libraries/src/TUF/DatabaseStorage.php

@@ -20,6 +20,9 @@
 
 /**
  * @since  5.1.0
+ *
+ * @internal Currently this class is only used for Joomla! updates and will be extended in the future to support 3rd party updates
+ *           Don't extend this class in your own code, it is subject to change without notice.
  */
 class DatabaseStorage extends StorageBase
 {

libraries/src/TUF/HttpLoader.php

@@ -17,6 +17,9 @@
 
 /**
  * @since  5.1.0
+ *
+ * @internal Currently this class is only used for Joomla! updates and will be extended in the future to support 3rd party updates
+ *           Don't extend this class in your own code, it is subject to change without notice.
  */
 class HttpLoader implements LoaderInterface
 {

libraries/src/TUF/TufFetcher.php

@@ -28,6 +28,9 @@
 
 /**
  * @since  5.1.0
+ *
+ * @internal Currently this class is only used for Joomla! updates and will be extended in the future to support 3rd party updates
+ *           Don't extend this class in your own code, it is subject to change without notice.
  */
 class TufFetcher
 {

libraries/src/Updater/Adapter/TufAdapter.php

@@ -29,6 +29,9 @@
  * TUF Update Adapter Class
  *
  * @since   5.1.0
+ *
+ * @internal Currently this class is only used for Joomla! updates and will be extended in the future to support 3rd party updates
+ *           Don't extend this class in your own code, it is subject to change without notice.
  */
 class TufAdapter extends UpdateAdapter
 {

libraries/src/Updater/ConstraintChecker.php

@@ -13,6 +13,7 @@
 \defined('_JEXEC') or die;
 // phpcs:enable PSR1.Files.SideEffects
 
+use Joomla\CMS\Component\ComponentHelper;
 use Joomla\CMS\Factory;
 use Joomla\CMS\Filter\InputFilter;
 use Joomla\CMS\Version;
@@ -21,6 +22,8 @@
  * ConstraintChecker Class
  *
  * @since  5.1.0
+ *
+ * @internal Currently this class is only used for Joomla! updates and will be extended in the future to support 3rd party updates
  */
 class ConstraintChecker
 {
@@ -34,16 +37,33 @@ class ConstraintChecker
      */
     protected \stdClass $failedEnvironmentConstraints;
 
+    /**
+     * The channel to check the contraints against
+     *
+     * @var string
+     */
+    protected $channel;
+
     /**
      * Constructor, used to populate the failed
      *
+     * @param string|null $channel  The channel to be used for updating
+     *
      * @return  void
      *
      * @since   5.1.0
      */
-    public function __construct()
+    public function __construct($channel = null)
     {
         $this->failedEnvironmentConstraints = new \stdClass();
+
+        if (!isset($channel)) {
+            $params = ComponentHelper::getParams('com_joomlaupdate');
+
+            $channel = (Version::MAJOR_VERSION + ($params->get('updatesource', 'default') == 'next' ? 1 : 0)) . '.x';
+        }
+
+        $this->channel = $channel;
     }
 
     /**
@@ -68,6 +88,11 @@ public function check(array $candidate, $minimumStability = Updater::STABILITY_S
             return false;
         }
 
+        // Check channel
+        if (isset($candidate['channel']) && $candidate['channel'] !== $this->channel) {
+            return false;
+        }
+
         $result = true;
 
         // Check php_minimum, assume true when not set

tests/Unit/Libraries/Cms/Updater/ConstraintCheckerTest.php

@@ -12,6 +12,7 @@
 
 use Joomla\CMS\Factory;
 use Joomla\CMS\Updater\ConstraintChecker;
+use Joomla\CMS\Version;
 use Joomla\Database\DatabaseDriver;
 use Joomla\Tests\Unit\UnitTestCase;
 
@@ -40,7 +41,7 @@ class ConstraintCheckerTest extends UnitTestCase
      */
     protected function setUp(): void
     {
-        $this->checker = new ConstraintChecker();
+        $this->checker = new ConstraintChecker(Version::MAJOR_VERSION . '.x');
     }
 
     /**