Issue #3013197 by tim.plunkett: Cloning an implementation of SectionListInterface does not deep clone the Section or SectionComponent objects

core/modules/layout_builder/src/Section.php

@@ -356,4 +356,13 @@ class Section {
     );
   }
 
+  /**
+   * Magic method: Implements a deep clone.
+   */
+  public function __clone() {
+    foreach ($this->components as $uuid => $component) {
+      $this->components[$uuid] = clone $component;
+    }
+  }
+
 }

core/modules/layout_builder/src/SectionStorage/SectionStorageTrait.php

@@ -111,4 +111,17 @@ trait SectionStorageTrait {
     return isset($this->getSections()[$delta]);
   }
 
+  /**
+   * Magic method: Implements a deep clone.
+   */
+  public function __clone() {
+    $sections = $this->getSections();
+
+    foreach ($sections as $delta => $item) {
+      $sections[$delta] = clone $item;
+    }
+
+    $this->setSections($sections);
+  }
+
 }

core/modules/layout_builder/tests/src/Kernel/SectionStorageTestBase.php

@@ -137,6 +137,17 @@ abstract class SectionStorageTestBase extends EntityKernelTestBase {
     $this->assertSections($expected);
   }
 
+  /**
+   * Tests __clone().
+   */
+  public function testClone() {
+    $this->assertSame([], $this->sectionStorage->getSection(0)->getLayoutSettings());
+
+    $new_section_storage = clone $this->sectionStorage;
+    $new_section_storage->getSection(0)->setLayoutSettings(['asdf' => 'qwer']);
+    $this->assertSame([], $this->sectionStorage->getSection(0)->getLayoutSettings());
+  }
+
   /**
    * Asserts that the field list has the expected sections.
    *