Issue #3258590 by kunal.sachdev: Various method missing return types

package_manager/src/Event/PreOperationStageEvent.php

@@ -39,7 +39,7 @@ abstract class PreOperationStageEvent extends StageEvent {
   /**
    * Adds error information to the event.
    */
-  public function addError(array $messages, ?TranslatableMarkup $summary = NULL) {
+  public function addError(array $messages, ?TranslatableMarkup $summary = NULL): void {
     $this->results[] = ValidationResult::createError($messages, $summary);
   }
 

package_manager/tests/modules/package_manager_bypass/src/InvocationRecorderBase.php

@@ -27,7 +27,7 @@ abstract class InvocationRecorderBase {
    * @param mixed ...$arguments
    *   The arguments that the main class method was called with.
    */
-  protected function saveInvocationArguments(...$arguments) {
+  protected function saveInvocationArguments(...$arguments): void {
     $invocations = $this->getInvocationArguments();
     $invocations[] = $arguments;
     \Drupal::state()->set(static::class, $invocations);

src/Event/ReadinessCheckEvent.php

@@ -66,7 +66,7 @@ class ReadinessCheckEvent extends PreOperationStageEvent {
   /**
    * Adds warning information to the event.
    */
-  public function addWarning(array $messages, ?TranslatableMarkup $summary = NULL) {
+  public function addWarning(array $messages, ?TranslatableMarkup $summary = NULL): void {
     $this->results[] = ValidationResult::createWarning($messages, $summary);
   }
 

tests/src/Functional/UpdateLockTest.php

@@ -37,7 +37,7 @@ class UpdateLockTest extends AutomaticUpdatesFunctionalTestBase {
   /**
    * Tests that only user who started an update can continue through it.
    */
-  public function testLock() {
+  public function testLock(): void {
     $page = $this->getSession()->getPage();
     $assert_session = $this->assertSession();
     $this->setCoreVersion('9.8.0');

tests/src/Functional/UpdaterFormTest.php

@@ -238,7 +238,7 @@ class UpdaterFormTest extends AutomaticUpdatesFunctionalTestBase {
   /**
    * Tests deleting an existing update.
    */
-  public function testDeleteExistingUpdate() {
+  public function testDeleteExistingUpdate(): void {
     $conflict_message = 'Cannot begin an update because another Composer operation is currently in progress.';
 
     $assert_session = $this->assertSession();

tests/src/Kernel/UpdaterTest.php

@@ -33,7 +33,7 @@ class UpdaterTest extends AutomaticUpdatesKernelTestBase {
   /**
    * Tests that correct versions are staged after calling ::begin().
    */
-  public function testCorrectVersionsStaged() {
+  public function testCorrectVersionsStaged(): void {
     $this->setReleaseMetadata(__DIR__ . '/../../fixtures/release-history/drupal.9.8.1-security.xml');
 
     // Create a user who will own the stage even after the container is rebuilt.