Issue #2363647 by benjy: Cannot programatically update books

core/modules/book/src/BookManager.php

@@ -243,9 +243,14 @@ public function updateOutline(NodeInterface $node) {
       return FALSE;
     }
 
-    if (!empty($node->book['bid']) && $node->book['bid'] == 'new') {
-      // New nodes that are their own book.
-      $node->book['bid'] = $node->id();
+    if (!empty($node->book['bid'])) {
+      if ($node->book['bid'] == 'new') {
+        // New nodes that are their own book.
+        $node->book['bid'] = $node->id();
+      }
+      elseif (!isset($node->book['original_bid'])) {
+        $node->book['original_bid'] = $node->book['bid'];
+      }
     }
 
     // Ensure we create a new book link if either the node itself is new, or the

core/modules/book/src/Tests/BookTest.php

@@ -166,6 +166,11 @@ function testBook() {
     $this->book = $other_book;
     $this->checkBookNode($other_book, array($node), FALSE, FALSE, $node, array());
     $this->checkBookNode($node, NULL, $other_book, $other_book, FALSE, array($other_book));
+
+    // Test that we can save a book programatically.
+    $this->drupalLogin($this->book_author);
+    $book = $this->createBookNode('new');
+    $book->save();
   }
 
   /**