Container - Use ClassScanner to setup HookListeners. Add test.

Before: While setting up the container-cache, it scans for these patterns:

* BAOs implementing HookInterface
* BAOs implementing EventDispatcherInterface

After: While setting up the container-cache, it scans for these patterns:

* BAOs implementing HookInterface (*unchanged*)
* BAOs implementing EventDispatcherInterface (*unchanged*)
* Extensions for classes (./Civi and ./CRM) implementing HookInterface (*new*)

Comment: For the moment, the `EventDispatcherInterface` is not (on its own)
sufficient to activate auto-registration.  This is because (1) the interface
is quite common in the world-at-large, so we'd prone to over-listening and
(2) we don't control the versioning-cycle, so the dephell is likely worse.

However, if you really want it, I think that it will pick up classes that
implement both `HookInterface` and `EventDispatcherInterface`.

Civi/Core/Container.php

@@ -375,12 +375,15 @@ public function createContainer() {
     ))->addTag('kernel.event_subscriber')->setPublic(TRUE);
 
     $dispatcherDefn = $container->getDefinition('dispatcher');
-    foreach (\CRM_Core_DAO_AllCoreTables::getBaoClasses() as $baoEntity => $baoClass) {
-      $listenerMap = EventScanner::findListeners($baoClass, $baoEntity);
+    $baoClasses = array_flip(\CRM_Core_DAO_AllCoreTables::getBaoClasses());
+    $hookClasses = ClassScanner::get(['interface' => HookInterface::class]);
+    $allEventClasses = array_merge(array_keys($baoClasses), $hookClasses);
+    foreach ($allEventClasses as $eventClass) {
+      $listenerMap = EventScanner::findListeners($eventClass, $baoClasses[$eventClass] ?? NULL);
       if ($listenerMap) {
-        $file = (new \ReflectionClass($baoClass))->getFileName();
+        $file = (new \ReflectionClass($eventClass))->getFileName();
         $container->addResource(new \Symfony\Component\Config\Resource\FileResource($file));
-        $dispatcherDefn->addMethodCall('addListenerMap', [$baoClass, $listenerMap]);
+        $dispatcherDefn->addMethodCall('addListenerMap', [$eventClass, $listenerMap]);
       }
     }
 

mixin/interface-php@1/example/CRM/Shimmy/ShimmyHooks.php

@@ -0,0 +1,9 @@
+<?php
+
+class CRM_Shimmy_ShimmyHooks implements \Civi\Core\HookInterface {
+
+  public static function hook_civicrm_shimmyFooBar(array &$data, string $for): void {
+    $data[] = "hello $for";
+  }
+
+}

mixin/interface-php@1/example/tests/mixin/InterfaceTest.php

@@ -20,22 +20,38 @@ public function testInstalled($cv) {
     // Assert that WorkflowMessageInterface's are registered.
     $items = $cv->api4('WorkflowMessage', 'get', ['where' => [['name', '=', 'shimmy_message_example']]]);
     $this->assertEquals('CRM_Shimmy_ShimmyMessage', $items[0]['class']);
+
+    // Assert that HookInterface's are registered.
+    $hookData = $this->fireHookShimmyFooBar($cv);
+    $this->assertEquals(['hello world'], $hookData);
   }
 
   public function testDisabled($cv) {
     // Assert that WorkflowMessageInterface's are removed.
     $items = $cv->api4('WorkflowMessage', 'get', ['where' => [['name', '=', 'shimmy_message_example']]]);
     $this->assertEmpty($items);
+
+    // Assert that HookInterface's are removed.
+    $hookData = $this->fireHookShimmyFooBar($cv);
+    $this->assertEquals([], $hookData);
   }
 
   public function testUninstalled($cv) {
     // Assert that WorkflowMessageInterface's are removed.
     $items = $cv->api4('WorkflowMessage', 'get', ['where' => [['name', '=', 'shimmy_message_example']]]);
     $this->assertEmpty($items);
+
+    // Assert that HookInterface's are removed.
+    $hookData = $this->fireHookShimmyFooBar($cv);
+    $this->assertEquals([], $hookData);
   }
 
   protected static function getPath($suffix = ''): string {
     return dirname(__DIR__, 2) . $suffix;
   }
 
+  protected function fireHookShimmyFooBar($cv): array {
+    return $cv->phpEval('$d=[]; Civi::dispatcher()->dispatch("hook_civicrm_shimmyFooBar", \Civi\Core\Event\GenericHookEvent::create(["data"=>&$d,"for"=>"world"])); return $d;');
+  }
+
 }

tests/extensions/shimmy/tests/phpunit/E2E/Shimmy/LifecycleTest.php

@@ -109,6 +109,11 @@ public function api4($entity, $action, $params): array {
         return (array) civicrm_api4($entity, $action, $params);
       }
 
+      public function phpEval(string $expr): array {
+        // phpcs:ignore
+        return eval($expr);
+      }
+
     };
   }
 
@@ -124,6 +129,10 @@ public function api4($entity, $action, $params): array {
         return $this->cv('api4 --in=json ' . escapeshellarg("$entity.$action"), json_encode($params));
       }
 
+      public function phpEval(string $expr): array {
+        return $this->cv('php:eval ' . escapeshellarg($expr));
+      }
+
       /**
        * Call the "cv" command.
        *