Replace trait alias with isAlwaysRun() in HookEssentials

The `use HookEssentials { register as protected parentRegister; }` alias
construct in `LoginButtonHook` and `RequestHook` is harder to read than a
simple method override. A `protected static isAlwaysRun()` default on the
trait lets subclasses declare their intent without redefining `register()`.

A static property was not viable here: PHP forbids redefining a trait
property in a using class with a different initial value.

Author: lippserd

library/Icinga/Application/Hook/HookEssentials.php

@@ -52,10 +52,26 @@ public static function first(): ?static
     /**
      * Register the hook
      *
-     * @param bool $alwaysRun Whether to always run the hook, without permission check
+     * @param ?bool $alwaysRun Whether to always run the hook without permission
+     *                         check. Defaults to {@see isAlwaysRun()}.
      */
-    public static function register(bool $alwaysRun = false): void
+    public static function register(?bool $alwaysRun = null): void
     {
-        Hook::register(static::getHookName(), static::class, static::class, $alwaysRun);
+        Hook::register(
+            static::getHookName(),
+            static::class,
+            static::class,
+            $alwaysRun ?? static::isAlwaysRun()
+        );
+    }
+
+    /**
+     * Get whether the hook always runs without a permission check
+     *
+     * Override this in a hook base class to change the default.
+     */
+    protected static function isAlwaysRun(): bool
+    {
+        return false;
     }
 }

library/Icinga/Application/Hook/LoginButtonHook.php

@@ -16,8 +16,19 @@
  */
 abstract class LoginButtonHook
 {
-    use HookEssentials {
-        register as protected parentRegister;
+    use HookEssentials;
+
+    /**
+     * Always runs without a permission check
+     *
+     * Login button hooks are intended to render on the login page, where
+     * permissions are not applicable.
+     *
+     * @return bool
+     */
+    protected static function isAlwaysRun(): bool
+    {
+        return true;
     }
 
     final protected static function getHookName(): string
@@ -34,14 +45,4 @@ final protected static function getHookName(): string
      * @return LoginButton[]
      */
     abstract public function getButtons(): array;
-
-    /**
-     * Register a hook provider
-     *
-     * Always runs the hook, without permission check. Latter makes no sense on the login page.
-     */
-    public static function register(): void
-    {
-        static::parentRegister(true);
-    }
 }

library/Icinga/Application/Hook/RequestHook.php

@@ -11,8 +11,19 @@
 
 abstract class RequestHook
 {
-    use HookEssentials {
-        register as protected parentRegister;
+    use HookEssentials;
+
+    /**
+     * Always runs without a permission check
+     *
+     * Request hooks are system-level concerns that fire on every request as
+     * part of the framework dispatch cycle, independent of user permissions.
+     *
+     * @return bool
+     */
+    protected static function isAlwaysRun(): bool
+    {
+        return true;
     }
 
     final protected static function getHookName(): string
@@ -46,14 +57,4 @@ final public static function postDispatch(Request $request): void
             }
         }
     }
-
-    /**
-     * Register the class as a RequestHook implementation
-     *
-     * Call this method on your implementation during module initialization to make Icinga Web aware of your hook.
-     */
-    public static function register(): void
-    {
-        static::parentRegister(true);
-    }
 }