MDL-70427 task: correct missing component when queuing adhoc task.

If the task belongs to a component, and doesn't have it's own
component property set then we can lazy-load it based on class
namespace.

lib/classes/task/task_base.php

@@ -136,6 +136,28 @@ abstract class task_base {
      * @return string
      */
     public function get_component() {
+        if (empty($this->component)) {
+            // The component should be the root of the class namespace.
+            $classname = get_class($this);
+            $parts = explode('\\', $classname);
+
+            if (count($parts) === 1) {
+                $component = substr($classname, 0, strpos($classname, '_task'));
+            } else {
+                [$component] = $parts;
+            }
+
+            // Load component information from plugin manager.
+            if ($component !== 'core' && strpos($component, 'core_') !== 0) {
+                $plugininfo = \core_plugin_manager::instance()->get_plugin_info($component);
+                if ($plugininfo && $plugininfo->component) {
+                    $this->set_component($plugininfo->component);
+                } else {
+                    debugging("Component not set and the class namespace does not match a valid component ({$component}).");
+                }
+            }
+        }
+
         return $this->component;
     }
 

lib/tests/adhoc_task_test.php

@@ -110,6 +110,46 @@ class core_adhoc_task_testcase extends advanced_testcase {
         \core\task\manager::adhoc_task_complete($task);
     }
 
+    /**
+     * Test queueing an adhoc task belonging to a component, where we set the task component accordingly
+     */
+    public function test_queue_adhoc_task_for_component(): void {
+        $this->resetAfterTest();
+
+        $task = new \mod_forum\task\refresh_forum_post_counts();
+        $task->set_component('mod_test');
+
+        \core\task\manager::queue_adhoc_task($task);
+        $this->assertDebuggingNotCalled();
+    }
+
+    /**
+     * Test queueing an adhoc task belonging to a component, where we do not set the task component
+     */
+    public function test_queue_task_for_component_without_set_component(): void {
+        $this->resetAfterTest();
+
+        $task = new \mod_forum\task\refresh_forum_post_counts();
+
+        \core\task\manager::queue_adhoc_task($task);
+        $this->assertDebuggingNotCalled();
+
+        // Assert the missing component was set.
+        $this->assertEquals('mod_forum', $task->get_component());
+    }
+
+    /**
+     * Test queueing an adhoc task belonging to an invalid component, where we do not set the task component
+     */
+    public function test_queue_task_for_invalid_component_without_set_component(): void {
+        $this->resetAfterTest();
+
+        $task = new \mod_fake\task\adhoc_component_task();
+
+        \core\task\manager::queue_adhoc_task($task);
+        $this->assertDebuggingCalled('Component not set and the class namespace does not match a valid component (mod_fake).');
+    }
+
     /**
      * Test empty set of adhoc tasks
      */

lib/tests/fixtures/task_fixtures.php

@@ -62,3 +62,11 @@ class scheduled_test3_task extends \core\task\scheduled_task {
     public function execute() {
     }
 }
+
+namespace mod_fake\task;
+
+class adhoc_component_task extends \core\task\adhoc_task {
+    public function execute() {
+
+    }
+}