Issue #3174903 by Niklan, ygoex: Error: Call to a member function getRegion() on null in hook_theme_suggestions_block_alter()

src/View/BlockViewBuilder.php

@@ -139,7 +139,7 @@ class BlockViewBuilder {
       if ($wrapper && !Element::isEmpty($build['content'])) {
         $build += [
           '#theme' => 'block',
-          '#id' => $configuration['id'] ?? $id,
+          '#id' => $configuration['id'] ?? NULL,
           '#attributes' => [],
           '#contextual_links' => [],
           '#configuration' => $block_plugin->getConfiguration(),

tests/src/Kernel/BlockViewBuilderTest.php

@@ -46,7 +46,7 @@ final class BlockViewBuilderTest extends KernelTestBase {
         ],
       ],
       '#theme' => 'block',
-      '#id' => 'twig_tweak_test_foo',
+      '#id' => NULL,
       '#attributes' => [
         'id' => 'foo',
       ],
@@ -74,7 +74,7 @@ final class BlockViewBuilderTest extends KernelTestBase {
       ],
     ];
     self::assertSame($expected_build, $build);
-    self::assertSame('<div id="block-twig-tweak-test-foo">Foo</div>', $this->renderPlain($build));
+    self::assertSame('<div id="foo">Foo</div>', $this->renderPlain($build));
 
     // -- Non-default configuration.
     $configuration = [