From f4eb12b0d540b24bd759765a27ad7b8e770a6df2 Mon Sep 17 00:00:00 2001
From: Benni Mack <benni@typo3.org>
Date: Fri, 22 Nov 2019 19:39:23 +0100
Subject: [PATCH] [FEATURE] Unified PSR-14 event for modifying the
 SystemInformationToolbarItem

The SystemInformationToolbarItem now has one unified PSR-14 Event instead
of the previous signals used by SignalSlotDispatcher.

New Event class is called:

- TYPO3\CMS\Backend\Backend\Event\SystemInformationToolbarCollectorEvent

and provides access to the actual SystemInformationToolbarItem allowing
to add messages or new systemInformation blocks by using the API methods
there.

The existing signals are deprecated, and all existing code is migrated
to the PSR-14 event.

Resolves: #89750
Related: #89733
Releases: master
Change-Id: I249c49f8d24b6e2dc73c2db7b4f7c15c9ccfa3fd
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/62390
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Susanne Moog <look@susi.dev>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>
---
 ...SystemInformationToolbarCollectorEvent.php | 40 ++++++++++++++
 .../SystemInformationToolbarItem.php          | 46 +++-------------
 .../Classes/Compatibility/SlotReplacement.php | 54 +++++++++++++++++++
 .../backend/Configuration/Services.yaml       |  7 +++
 .../SystemInformationController.php           | 18 ++++---
 .../sysext/belog/Configuration/Services.yaml  |  7 +++
 typo3/sysext/belog/ext_localconf.php          | 10 ----
 ...sInCoreExtensionMigratedToPSR-14Events.rst |  7 ++-
 ...sForExistingSignalSlotsInCoreExtension.rst |  3 ++
 .../extbase/Classes/SignalSlot/Dispatcher.php |  6 +++
 .../SystemInformation/Typo3VersionMessage.php | 19 +++----
 .../install/Configuration/Services.yaml       | 10 ++++
 typo3/sysext/install/ext_localconf.php        |  8 ---
 .../SystemInformation/ToolbarItemProvider.php | 22 ++++----
 .../scheduler/Configuration/Services.yaml     |  7 +++
 typo3/sysext/scheduler/ext_localconf.php      |  9 ----
 16 files changed, 171 insertions(+), 102 deletions(-)
 create mode 100644 typo3/sysext/backend/Classes/Backend/Event/SystemInformationToolbarCollectorEvent.php
 create mode 100644 typo3/sysext/backend/Classes/Compatibility/SlotReplacement.php
 delete mode 100644 typo3/sysext/belog/ext_localconf.php
 create mode 100644 typo3/sysext/install/Configuration/Services.yaml

diff --git a/typo3/sysext/backend/Classes/Backend/Event/SystemInformationToolbarCollectorEvent.php b/typo3/sysext/backend/Classes/Backend/Event/SystemInformationToolbarCollectorEvent.php
new file mode 100644
index 000000000000..5cab9ef3b511
--- /dev/null
+++ b/typo3/sysext/backend/Classes/Backend/Event/SystemInformationToolbarCollectorEvent.php
@@ -0,0 +1,40 @@
+<?php
+declare(strict_types = 1);
+namespace TYPO3\CMS\Backend\Backend\Event;
+
+/*
+ * This file is part of the TYPO3 CMS project.
+ *
+ * It is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License, either version 2
+ * of the License, or any later version.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE.txt file that was distributed with this source code.
+ *
+ * The TYPO3 project - inspiring people to share!
+ */
+
+use TYPO3\CMS\Backend\Backend\ToolbarItems\SystemInformationToolbarItem;
+
+/**
+ * An event to enrich the system information toolbar in the TYPO3 Backend top toolbar
+ * with various information
+ */
+final class SystemInformationToolbarCollectorEvent
+{
+    /**
+     * @var SystemInformationToolbarItem
+     */
+    private $toolbarItem;
+
+    public function __construct(SystemInformationToolbarItem $toolbarItem)
+    {
+        $this->toolbarItem = $toolbarItem;
+    }
+
+    public function getToolbarItem(): SystemInformationToolbarItem
+    {
+        return $this->toolbarItem;
+    }
+}
diff --git a/typo3/sysext/backend/Classes/Backend/ToolbarItems/SystemInformationToolbarItem.php b/typo3/sysext/backend/Classes/Backend/ToolbarItems/SystemInformationToolbarItem.php
index e62bd4b55176..d1895a7ef2f5 100644
--- a/typo3/sysext/backend/Classes/Backend/ToolbarItems/SystemInformationToolbarItem.php
+++ b/typo3/sysext/backend/Classes/Backend/ToolbarItems/SystemInformationToolbarItem.php
@@ -14,6 +14,8 @@ namespace TYPO3\CMS\Backend\Backend\ToolbarItems;
  * The TYPO3 project - inspiring people to share!
  */
 
+use Psr\EventDispatcher\EventDispatcherInterface;
+use TYPO3\CMS\Backend\Backend\Event\SystemInformationToolbarCollectorEvent;
 use TYPO3\CMS\Backend\Routing\UriBuilder;
 use TYPO3\CMS\Backend\Toolbar\Enumeration\InformationStatus;
 use TYPO3\CMS\Backend\Toolbar\ToolbarItemInterface;
@@ -27,8 +29,6 @@ use TYPO3\CMS\Core\Utility\CommandUtility;
 use TYPO3\CMS\Core\Utility\GeneralUtility;
 use TYPO3\CMS\Core\Utility\StringUtility;
 use TYPO3\CMS\Core\Utility\VersionNumberUtility;
-use TYPO3\CMS\Extbase\Object\ObjectManager;
-use TYPO3\CMS\Extbase\SignalSlot\Dispatcher;
 use TYPO3\CMS\Fluid\View\StandaloneView;
 
 /**
@@ -68,20 +68,18 @@ class SystemInformationToolbarItem implements ToolbarItemInterface
     protected $systemMessages = [];
 
     /**
-     * @var Dispatcher
+     * @var EventDispatcherInterface
      */
-    protected $signalSlotDispatcher;
+    protected $eventDispatcher;
 
     /**
      * @var int
      */
     protected $maximumCountInBadge = 99;
 
-    /**
-     * Constructor
-     */
-    public function __construct()
+    public function __construct(EventDispatcherInterface $eventDispatcher = null)
     {
+        $this->eventDispatcher = $eventDispatcher ?? GeneralUtility::getContainer()->get(EventDispatcherInterface::class);
         $this->getPageRenderer()->loadRequireJsModule('TYPO3/CMS/Backend/Toolbar/SystemInformationMenu');
         $this->highestSeverity = InformationStatus::cast(InformationStatus::STATUS_INFO);
     }
@@ -231,8 +229,7 @@ class SystemInformationToolbarItem implements ToolbarItemInterface
         $this->getGitRevision();
         $this->getOperatingSystem();
 
-        $this->emitGetSystemInformation();
-        $this->emitLoadMessages();
+        $this->eventDispatcher->dispatch(new SystemInformationToolbarCollectorEvent($this));
 
         $this->severityBadgeClass = !$this->highestSeverity->equals(InformationStatus::STATUS_NOTICE) ? 'badge-' . (string)$this->highestSeverity : '';
     }
@@ -371,22 +368,6 @@ class SystemInformationToolbarItem implements ToolbarItemInterface
         ];
     }
 
-    /**
-     * Emits the "getSystemInformation" signal
-     */
-    protected function emitGetSystemInformation()
-    {
-        $this->getSignalSlotDispatcher()->dispatch(__CLASS__, 'getSystemInformation', [$this]);
-    }
-
-    /**
-     * Emits the "loadMessages" signal
-     */
-    protected function emitLoadMessages()
-    {
-        $this->getSignalSlotDispatcher()->dispatch(__CLASS__, 'loadMessages', [$this]);
-    }
-
     /**
      * Returns a new standalone view, shorthand function
      *
@@ -433,17 +414,4 @@ class SystemInformationToolbarItem implements ToolbarItemInterface
     {
         return GeneralUtility::makeInstance(PageRenderer::class);
     }
-
-    /**
-     * Get the SignalSlot dispatcher
-     *
-     * @return Dispatcher
-     */
-    protected function getSignalSlotDispatcher()
-    {
-        if (!isset($this->signalSlotDispatcher)) {
-            $this->signalSlotDispatcher = GeneralUtility::makeInstance(ObjectManager::class)->get(Dispatcher::class);
-        }
-        return $this->signalSlotDispatcher;
-    }
 }
diff --git a/typo3/sysext/backend/Classes/Compatibility/SlotReplacement.php b/typo3/sysext/backend/Classes/Compatibility/SlotReplacement.php
new file mode 100644
index 000000000000..a0df516f0eb3
--- /dev/null
+++ b/typo3/sysext/backend/Classes/Compatibility/SlotReplacement.php
@@ -0,0 +1,54 @@
+<?php
+declare(strict_types = 1);
+namespace TYPO3\CMS\Backend\Compatibility;
+
+/*
+ * This file is part of the TYPO3 CMS project.
+ *
+ * It is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License, either version 2
+ * of the License, or any later version.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE.txt file that was distributed with this source code.
+ *
+ * The TYPO3 project - inspiring people to share!
+ */
+
+use TYPO3\CMS\Backend\Backend\Event\SystemInformationToolbarCollectorEvent;
+use TYPO3\CMS\Backend\Backend\ToolbarItems\SystemInformationToolbarItem;
+use TYPO3\CMS\Extbase\SignalSlot\Dispatcher as SignalSlotDispatcher;
+
+/**
+ * This class provides a replacement for all existing signals in EXT:backend of TYPO3 Core, which now act as a
+ * simple wrapper for PSR-14 events with a simple ("first prioritized") listener implementation.
+ *
+ * @internal Please note that this class will likely be removed in TYPO3 v11, and Extension Authors should
+ * switch to PSR-14 event listeners.
+ */
+class SlotReplacement
+{
+    /**
+     * @var SignalSlotDispatcher
+     */
+    protected $signalSlotDispatcher;
+
+    public function __construct(SignalSlotDispatcher $signalSlotDispatcher)
+    {
+        $this->signalSlotDispatcher = $signalSlotDispatcher;
+    }
+
+    public function onSystemInformationToolbarEvent(SystemInformationToolbarCollectorEvent $event): void
+    {
+        $this->signalSlotDispatcher->dispatch(
+            SystemInformationToolbarItem::class,
+            'getSystemInformation',
+            [$event->getToolbarItem()]
+        );
+        $this->signalSlotDispatcher->dispatch(
+            SystemInformationToolbarItem::class,
+            'loadMessages',
+            [$event->getToolbarItem()]
+        );
+    }
+}
diff --git a/typo3/sysext/backend/Configuration/Services.yaml b/typo3/sysext/backend/Configuration/Services.yaml
index c8814cea882e..d121c9d0c379 100644
--- a/typo3/sysext/backend/Configuration/Services.yaml
+++ b/typo3/sysext/backend/Configuration/Services.yaml
@@ -19,6 +19,13 @@ services:
   TYPO3\CMS\Backend\History\RecordHistoryRollback:
     public: true
 
+  # Listener for old Signal Slots
+  TYPO3\CMS\Backend\Compatibility\SlotReplacement:
+    tags:
+      - name: event.listener
+        identifier: 'legacy-slot'
+        method: 'onSystemInformationToolbarEvent'
+        event: TYPO3\CMS\Backend\Backend\Event\SystemInformationToolbarCollectorEvent
 
   # Category security checks for backend users
   TYPO3\CMS\Backend\Security\CategoryPermissionsAspect:
diff --git a/typo3/sysext/belog/Classes/Controller/SystemInformationController.php b/typo3/sysext/belog/Classes/Controller/SystemInformationController.php
index 031580a70290..3d92ac0e2575 100644
--- a/typo3/sysext/belog/Classes/Controller/SystemInformationController.php
+++ b/typo3/sysext/belog/Classes/Controller/SystemInformationController.php
@@ -15,7 +15,7 @@ namespace TYPO3\CMS\Belog\Controller;
  * The TYPO3 project - inspiring people to share!
  */
 
-use TYPO3\CMS\Backend\Backend\ToolbarItems\SystemInformationToolbarItem;
+use TYPO3\CMS\Backend\Backend\Event\SystemInformationToolbarCollectorEvent;
 use TYPO3\CMS\Backend\Routing\UriBuilder;
 use TYPO3\CMS\Backend\Toolbar\Enumeration\InformationStatus;
 use TYPO3\CMS\Core\Database\Connection;
@@ -24,10 +24,11 @@ use TYPO3\CMS\Core\Utility\GeneralUtility;
 use TYPO3\CMS\Extbase\Utility\LocalizationUtility;
 
 /**
- * Count newest exceptions for the system information menu
+ * Count latest exceptions for the system information menu.
+ *
  * @internal This class is a TYPO3 Backend implementation and is not considered part of the Public TYPO3 API.
  */
-class SystemInformationController
+final class SystemInformationController
 {
     /**
      * @var array
@@ -40,12 +41,13 @@ class SystemInformationController
     }
 
     /**
-     * Modifies the SystemInformation array
-     *
-     * @param SystemInformationToolbarItem $systemInformationToolbarItem
+     * Modifies the SystemInformation toolbar to inject a new message
+     * @param SystemInformationToolbarCollectorEvent $event
+     * @throws \TYPO3\CMS\Backend\Routing\Exception\RouteNotFoundException
      */
-    public function appendMessage(SystemInformationToolbarItem $systemInformationToolbarItem)
+    public function appendMessage(SystemInformationToolbarCollectorEvent $event): void
     {
+        $systemInformationToolbarItem = $event->getToolbarItem();
         // we can't use the extbase repository here as the required TypoScript may not be parsed yet
         $queryBuilder = GeneralUtility::makeInstance(ConnectionPool::class)->getQueryBuilderForTable('sys_log');
         $count = $queryBuilder->count('error')
@@ -82,7 +84,7 @@ class SystemInformationController
         }
     }
 
-    protected function fetchLastAccessTimestamp(): int
+    private function fetchLastAccessTimestamp(): int
     {
         if (!isset($this->backendUserConfiguration['systeminformation'])) {
             return 0;
diff --git a/typo3/sysext/belog/Configuration/Services.yaml b/typo3/sysext/belog/Configuration/Services.yaml
index 3dea960b038e..7b8163cd054f 100644
--- a/typo3/sysext/belog/Configuration/Services.yaml
+++ b/typo3/sysext/belog/Configuration/Services.yaml
@@ -6,3 +6,10 @@ services:
 
   TYPO3\CMS\Belog\:
     resource: '../Classes/*'
+
+  TYPO3\CMS\Belog\Controller\SystemInformationController:
+    tags:
+      - name: event.listener
+        identifier: 'belog/show-latest-errors'
+        method: 'appendMessage'
+        event: TYPO3\CMS\Backend\Backend\Event\SystemInformationToolbarCollectorEvent
diff --git a/typo3/sysext/belog/ext_localconf.php b/typo3/sysext/belog/ext_localconf.php
deleted file mode 100644
index 8040bedc86be..000000000000
--- a/typo3/sysext/belog/ext_localconf.php
+++ /dev/null
@@ -1,10 +0,0 @@
-<?php
-defined('TYPO3_MODE') or die();
-
-\TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\TYPO3\CMS\Extbase\SignalSlot\Dispatcher::class)
-    ->connect(
-        \TYPO3\CMS\Backend\Backend\ToolbarItems\SystemInformationToolbarItem::class,
-        'loadMessages',
-        \TYPO3\CMS\Belog\Controller\SystemInformationController::class,
-        'appendMessage'
-    );
diff --git a/typo3/sysext/core/Documentation/Changelog/master/Deprecation-89733-SignalSlotsInCoreExtensionMigratedToPSR-14Events.rst b/typo3/sysext/core/Documentation/Changelog/master/Deprecation-89733-SignalSlotsInCoreExtensionMigratedToPSR-14Events.rst
index 2ec0058af846..a44f9dcbe90e 100644
--- a/typo3/sysext/core/Documentation/Changelog/master/Deprecation-89733-SignalSlotsInCoreExtensionMigratedToPSR-14Events.rst
+++ b/typo3/sysext/core/Documentation/Changelog/master/Deprecation-89733-SignalSlotsInCoreExtensionMigratedToPSR-14Events.rst
@@ -17,11 +17,13 @@ which are a 1:1 equivalent:
 - :php:`TYPO3\CMS\Core\Database\ReferenceIndex::shouldExcludeTableFromReferenceIndex`
 - :php:`TYPO3\CMS\Core\Utility\ExtensionManagementUtility::tcaIsBeingBuilt`
 - :php:`TYPO3\CMS\Install\Service\SqlExpectedSchemaService::tablesDefinitionIsBeingBuilt`
-- :php:`\TYPO3\CMS\Core\Tree\TableConfiguration\DatabaseTreeDataProvider::PostProcessTreeData`
+- :php:`TYPO3\CMS\Core\Tree\TableConfiguration\DatabaseTreeDataProvider::PostProcessTreeData`
+- :php:`TYPO3\CMS\Backend\Backend\ToolbarItems\SystemInformationToolbarItem::getSystemInformation`
+- :php:`TYPO3\CMS\Backend\Backend\ToolbarItems\SystemInformationToolbarItem::loadMessages`
 
 In addition, the following public constant, marking a signal name, is deprecated:
 
-- :php:`\TYPO3\CMS\Core\Tree\TableConfiguration\DatabaseTreeDataProvider::SIGNAL_PostProcessTreeData`
+- :php:`TYPO3\CMS\Core\Tree\TableConfiguration\DatabaseTreeDataProvider::SIGNAL_PostProcessTreeData`
 
 
 Impact
@@ -46,5 +48,6 @@ Use the new PSR-14 alternatives:
 - :php:`TYPO3\CMS\Core\Configuration\Event\AfterTcaCompilationEvent`
 - :php:`TYPO3\CMS\Core\Database\Event\AlterTableDefinitionStatementsEvent`
 - :php:`TYPO3\CMS\Core\Tree\Event\ModifyTreeDataEvent`
+- :php:`TYPO3\CMS\Backend\Backend\Event\SystemInformationToolbarCollectorEvent`
 
 .. index:: PHP-API, FullyScanned, ext:core
diff --git a/typo3/sysext/core/Documentation/Changelog/master/Feature-89733-NewPSR-14EventsForExistingSignalSlotsInCoreExtension.rst b/typo3/sysext/core/Documentation/Changelog/master/Feature-89733-NewPSR-14EventsForExistingSignalSlotsInCoreExtension.rst
index 7529492de0fd..078fd11018a2 100644
--- a/typo3/sysext/core/Documentation/Changelog/master/Feature-89733-NewPSR-14EventsForExistingSignalSlotsInCoreExtension.rst
+++ b/typo3/sysext/core/Documentation/Changelog/master/Feature-89733-NewPSR-14EventsForExistingSignalSlotsInCoreExtension.rst
@@ -19,6 +19,7 @@ The following new PSR-14 events have been introduced:
 - :php:`TYPO3\CMS\Core\Configuration\Event\AfterTcaCompilationEvent`
 - :php:`TYPO3\CMS\Core\Database\Event\AlterTableDefinitionStatementsEvent`
 - :php:`TYPO3\CMS\Core\Tree\Event\ModifyTreeDataEvent`
+- :php:`TYPO3\CMS\Backend\Backend\Event\SystemInformationToolbarCollectorEvent`
 
 They replace the existing Extbase-based Signal Slots
 
@@ -28,6 +29,8 @@ They replace the existing Extbase-based Signal Slots
 - :php:`TYPO3\CMS\Core\Utility\ExtensionManagementUtility::tcaIsBeingBuilt`
 - :php:`TYPO3\CMS\Install\Service\SqlExpectedSchemaService::tablesDefinitionIsBeingBuilt`
 - :php:`TYPO3\CMS\Core\Tree\TableConfiguration\DatabaseTreeDataProvider::PostProcessTreeData`
+- :php:`TYPO3\CMS\Backend\Backend\ToolbarItems\SystemInformationToolbarItem::getSystemInformation`
+- :php:`TYPO3\CMS\Backend\Backend\ToolbarItems\SystemInformationToolbarItem::loadMessages`
 
 
 Impact
diff --git a/typo3/sysext/extbase/Classes/SignalSlot/Dispatcher.php b/typo3/sysext/extbase/Classes/SignalSlot/Dispatcher.php
index 4d1df2e157a4..1d239c58f40e 100644
--- a/typo3/sysext/extbase/Classes/SignalSlot/Dispatcher.php
+++ b/typo3/sysext/extbase/Classes/SignalSlot/Dispatcher.php
@@ -17,6 +17,8 @@ namespace TYPO3\CMS\Extbase\SignalSlot;
  */
 
 use Psr\Log\LoggerInterface;
+use TYPO3\CMS\Backend\Backend\Event\SystemInformationToolbarCollectorEvent;
+use TYPO3\CMS\Backend\Backend\ToolbarItems\SystemInformationToolbarItem;
 use TYPO3\CMS\Core\Configuration\Event\AfterTcaCompilationEvent;
 use TYPO3\CMS\Core\Database\Event\AlterTableDefinitionStatementsEvent;
 use TYPO3\CMS\Core\Database\ReferenceIndex;
@@ -172,6 +174,10 @@ class Dispatcher implements \TYPO3\CMS\Core\SingletonInterface
         DatabaseTreeDataProvider::class => [
             'PostProcessTreeData' => ModifyTreeDataEvent::class,
         ],
+        SystemInformationToolbarItem::class => [
+            'getSystemInformation' => SystemInformationToolbarCollectorEvent::class,
+            'loadMessages' => SystemInformationToolbarCollectorEvent::class
+        ]
     ];
 
     /**
diff --git a/typo3/sysext/install/Classes/SystemInformation/Typo3VersionMessage.php b/typo3/sysext/install/Classes/SystemInformation/Typo3VersionMessage.php
index fbf52638a7ba..1bf7af96a308 100644
--- a/typo3/sysext/install/Classes/SystemInformation/Typo3VersionMessage.php
+++ b/typo3/sysext/install/Classes/SystemInformation/Typo3VersionMessage.php
@@ -16,7 +16,7 @@ namespace TYPO3\CMS\Install\SystemInformation;
  * The TYPO3 project - inspiring people to share!
  */
 
-use TYPO3\CMS\Backend\Backend\ToolbarItems\SystemInformationToolbarItem;
+use TYPO3\CMS\Backend\Backend\Event\SystemInformationToolbarCollectorEvent;
 use TYPO3\CMS\Backend\Toolbar\Enumeration\InformationStatus;
 use TYPO3\CMS\Core\Utility\GeneralUtility;
 use TYPO3\CMS\Extbase\Utility\LocalizationUtility;
@@ -24,26 +24,19 @@ use TYPO3\CMS\Install\Service\CoreVersionService;
 use TYPO3\CMS\Install\Service\Exception\RemoteFetchException;
 
 /**
- * Count newest exceptions for the system information menu
+ * Modifies the SystemInformation information to add a new message if you are running the latest TYPO3 Version
  *
  * @internal This class is only meant to be used within EXT:install and is not part of the TYPO3 Core API.
  */
-class Typo3VersionMessage
+final class Typo3VersionMessage
 {
-    /**
-     * Modifies the SystemInformation array
-     *
-     * @param SystemInformationToolbarItem $systemInformationToolbarItem
-     */
-    public function appendMessage(SystemInformationToolbarItem $systemInformationToolbarItem): void
+    public function appendMessage(SystemInformationToolbarCollectorEvent $event): void
     {
+        $systemInformationToolbarItem = $event->getToolbarItem();
         $coreVersionService = GeneralUtility::makeInstance(CoreVersionService::class);
-
         try {
             if ($coreVersionService->isVersionActivelyMaintained()) {
-                $isYoungerPatchReleaseAvailable = $coreVersionService->isYoungerPatchReleaseAvailable();
-
-                if (true === $isYoungerPatchReleaseAvailable) {
+                if ($coreVersionService->isYoungerPatchReleaseAvailable()) {
                     $release = $coreVersionService->getYoungestPatchRelease();
 
                     if ($coreVersionService->isUpdateSecurityRelevant()) {
diff --git a/typo3/sysext/install/Configuration/Services.yaml b/typo3/sysext/install/Configuration/Services.yaml
new file mode 100644
index 000000000000..15f76349eb9f
--- /dev/null
+++ b/typo3/sysext/install/Configuration/Services.yaml
@@ -0,0 +1,10 @@
+services:
+  TYPO3\CMS\Install\SystemInformation\Typo3VersionMessage:
+    autowire: true
+    autoconfigure: true
+    public: false
+    tags:
+      - name: event.listener
+        identifier: 'install/show-latest-errors'
+        method: 'appendMessage'
+        event: TYPO3\CMS\Backend\Backend\Event\SystemInformationToolbarCollectorEvent
diff --git a/typo3/sysext/install/ext_localconf.php b/typo3/sysext/install/ext_localconf.php
index 825ef3052bb3..72b5e6cb75b7 100644
--- a/typo3/sysext/install/ext_localconf.php
+++ b/typo3/sysext/install/ext_localconf.php
@@ -73,11 +73,3 @@ $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['reports']['tx_reports']['status']['pr
 if (!\TYPO3\CMS\Core\Core\Environment::isCli()) {
     $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['reports']['tx_reports']['status']['providers']['system'][] = \TYPO3\CMS\Install\Report\EnvironmentStatusReport::class;
 }
-
-\TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\TYPO3\CMS\Extbase\SignalSlot\Dispatcher::class)
-    ->connect(
-        \TYPO3\CMS\Backend\Backend\ToolbarItems\SystemInformationToolbarItem::class,
-        'loadMessages',
-        \TYPO3\CMS\Install\SystemInformation\Typo3VersionMessage::class,
-        'appendMessage'
-    );
diff --git a/typo3/sysext/scheduler/Classes/SystemInformation/ToolbarItemProvider.php b/typo3/sysext/scheduler/Classes/SystemInformation/ToolbarItemProvider.php
index 2e4bcb0a05e6..68135a590b68 100644
--- a/typo3/sysext/scheduler/Classes/SystemInformation/ToolbarItemProvider.php
+++ b/typo3/sysext/scheduler/Classes/SystemInformation/ToolbarItemProvider.php
@@ -15,7 +15,7 @@ namespace TYPO3\CMS\Scheduler\SystemInformation;
  * The TYPO3 project - inspiring people to share!
  */
 
-use TYPO3\CMS\Backend\Backend\ToolbarItems\SystemInformationToolbarItem;
+use TYPO3\CMS\Backend\Backend\Event\SystemInformationToolbarCollectorEvent;
 use TYPO3\CMS\Backend\Routing\UriBuilder;
 use TYPO3\CMS\Backend\Toolbar\Enumeration\InformationStatus;
 use TYPO3\CMS\Backend\Utility\BackendUtility;
@@ -25,9 +25,9 @@ use TYPO3\CMS\Core\Registry;
 use TYPO3\CMS\Core\Utility\GeneralUtility;
 
 /**
- * Add information about the scheduler configuration to the system information toolbar
+ * Event listener to display information about last automated run, as stored in the system registry.
  */
-class ToolbarItemProvider
+final class ToolbarItemProvider
 {
     /**
      * Scheduler last run registry information
@@ -44,13 +44,9 @@ class ToolbarItemProvider
         $this->lastRunInformation = GeneralUtility::makeInstance(Registry::class)->get('tx_scheduler', 'lastRun', []);
     }
 
-    /**
-     * Display information about last automated run, as stored in the system registry
-     *
-     * @param SystemInformationToolbarItem $systemInformationToolbarItem
-     */
-    public function getItem(SystemInformationToolbarItem $systemInformationToolbarItem): void
+    public function getItem(SystemInformationToolbarCollectorEvent $event): void
     {
+        $systemInformationToolbarItem = $event->getToolbarItem();
         // No tasks configured, so nothing is shown at all
         if (!$this->hasConfiguredTasks()) {
             return;
@@ -119,7 +115,7 @@ class ToolbarItemProvider
      *
      * @return bool
      */
-    protected function schedulerWasExecuted(): bool
+    private function schedulerWasExecuted(): bool
     {
         return !empty($this->lastRunInformation);
     }
@@ -129,7 +125,7 @@ class ToolbarItemProvider
      *
      * @return bool
      */
-    protected function lastRunInfoExists(): bool
+    private function lastRunInfoExists(): bool
     {
         return !empty($this->lastRunInformation['end'])
             || !empty($this->lastRunInformation['start'])
@@ -141,7 +137,7 @@ class ToolbarItemProvider
      *
      * @return bool
      */
-    protected function hasConfiguredTasks(): bool
+    private function hasConfiguredTasks(): bool
     {
         $queryBuilder = GeneralUtility::makeInstance(ConnectionPool::class)->getQueryBuilderForTable('tx_scheduler_task');
         $queryBuilder->getRestrictions()->removeAll();
@@ -157,7 +153,7 @@ class ToolbarItemProvider
     /**
      * @return LanguageService
      */
-    protected function getLanguageService(): LanguageService
+    private function getLanguageService(): LanguageService
     {
         return $GLOBALS['LANG'];
     }
diff --git a/typo3/sysext/scheduler/Configuration/Services.yaml b/typo3/sysext/scheduler/Configuration/Services.yaml
index e8547339921d..c719171541e8 100644
--- a/typo3/sysext/scheduler/Configuration/Services.yaml
+++ b/typo3/sysext/scheduler/Configuration/Services.yaml
@@ -6,3 +6,10 @@ services:
 
   TYPO3\CMS\Scheduler\:
     resource: '../Classes/*'
+
+  TYPO3\CMS\Scheduler\SystemInformation\ToolbarItemProvider:
+    tags:
+      - name: event.listener
+        identifier: 'scheduler/show-latest-errors'
+        method: 'getItem'
+        event: TYPO3\CMS\Backend\Backend\Event\SystemInformationToolbarCollectorEvent
diff --git a/typo3/sysext/scheduler/ext_localconf.php b/typo3/sysext/scheduler/ext_localconf.php
index ed3f42ac02dd..1f8ab51df139 100644
--- a/typo3/sysext/scheduler/ext_localconf.php
+++ b/typo3/sysext/scheduler/ext_localconf.php
@@ -132,12 +132,3 @@ $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['scheduler']['frequencyOptions'] = [
     '*/20 * * * *' =>  'LLL:EXT:scheduler/Resources/Private/Language/locallang.xlf:command.example3',
     '0 7 * * 2' =>  'LLL:EXT:scheduler/Resources/Private/Language/locallang.xlf:command.example4',
 ];
-
-// Add system information toolbar item
-\TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\TYPO3\CMS\Extbase\SignalSlot\Dispatcher::class)
-    ->connect(
-        \TYPO3\CMS\Backend\Backend\ToolbarItems\SystemInformationToolbarItem::class,
-        'getSystemInformation',
-        \TYPO3\CMS\Scheduler\SystemInformation\ToolbarItemProvider::class,
-        'getItem'
-    );
-- 
GitLab