From 2aa54e028438d89d5ac85e9400a2badf8c651dfe Mon Sep 17 00:00:00 2001
From: Toon Verwerft <toonverwerft@gmail.com>
Date: Thu, 26 Jan 2023 18:43:17 +0100
Subject: [PATCH] Fix mutable nodeList reference during traversal

---
 src/Xml/Dom/Traverser/Traverser.php       |  3 +-
 src/Xml/ErrorHandling/detect_issues.php   |  2 -
 tests/Xml/Dom/Traverser/TraverserTest.php | 48 +++++++++++++++++++++++
 3 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/src/Xml/Dom/Traverser/Traverser.php b/src/Xml/Dom/Traverser/Traverser.php
index f1f7f58..46a8a2a 100644
--- a/src/Xml/Dom/Traverser/Traverser.php
+++ b/src/Xml/Dom/Traverser/Traverser.php
@@ -6,6 +6,7 @@
 
 use DOMNode;
 use function VeeWee\Xml\Dom\Locator\Attribute\attributes_list;
+use function VeeWee\Xml\Dom\Locator\Node\children;
 
 final class Traverser
 {
@@ -30,7 +31,7 @@ public function traverse(DOMNode $node): DOMNode
             $this->traverse($attribute);
         }
 
-        foreach ($node->childNodes as $child) {
+        foreach (children($node) as $child) {
             $this->traverse($child);
         }
 
diff --git a/src/Xml/ErrorHandling/detect_issues.php b/src/Xml/ErrorHandling/detect_issues.php
index bd80fc6..37ad2e5 100644
--- a/src/Xml/ErrorHandling/detect_issues.php
+++ b/src/Xml/ErrorHandling/detect_issues.php
@@ -4,7 +4,6 @@
 
 namespace VeeWee\Xml\ErrorHandling;
 
-use LibXMLError;
 use Psl\Result;
 use Psl\Result\ResultInterface;
 
@@ -31,7 +30,6 @@ function detect_issues(callable $run): array
 
     $result = Result\wrap($run(...));
 
-    /** @var list<LibXMLError> $errors */
     $errors = libxml_get_errors();
     libxml_clear_errors();
     libxml_use_internal_errors($previousErrorReporting);
diff --git a/tests/Xml/Dom/Traverser/TraverserTest.php b/tests/Xml/Dom/Traverser/TraverserTest.php
index 1d91927..c343ff5 100644
--- a/tests/Xml/Dom/Traverser/TraverserTest.php
+++ b/tests/Xml/Dom/Traverser/TraverserTest.php
@@ -11,6 +11,7 @@
 use VeeWee\Xml\Dom\Traverser\Traverser;
 use VeeWee\Xml\Dom\Traverser\Visitor\AbstractVisitor;
 use function VeeWee\Xml\Dom\Builder\attribute;
+use function VeeWee\Xml\Dom\Configurator\comparable;
 use function VeeWee\Xml\Dom\Locator\document_element;
 use function VeeWee\Xml\Dom\Mapper\xml_string;
 use function VeeWee\Xml\Dom\Predicate\is_attribute;
@@ -130,4 +131,51 @@ public function onNodeLeave(DOMNode $node): Action
 
         static::assertXmlStringEqualsXmlString($doc->toXmlString(), '<hello enter="yes" leave="yes" />');
     }
+
+    
+    public function test_it_can_recursively_remove_empty_nodes(): void
+    {
+        $doc = Document::fromXmlString(
+            <<<EOXML
+            <movies>
+                <movie>
+                    <name>Terminator</name>
+                    <genre>
+                        <action />
+                        <romance />
+                    </genre>
+                    <prices>
+                        <oscar />
+                    </prices>
+                </movie>
+            </movies>
+        EOXML
+        );
+
+        $transformedNode = $doc->traverse(new class extends AbstractVisitor {
+            public function onNodeLeave(DOMNode $node): Action
+            {
+                if (!is_element($node)) {
+                    return new Action\Noop();
+                }
+
+                if (trim($node->textContent) !== '') {
+                    return new Action\Noop();
+                }
+
+                return new Action\RemoveNode();
+            }
+        });
+
+        $actual = Document::fromXmlNode($transformedNode, comparable());
+        $expected = Document::fromXmlString(<<<EOXML
+            <movies>
+                <movie>
+                    <name>Terminator</name>
+                </movie>
+            </movies>
+        EOXML, comparable());
+
+        static::assertSame($actual->toXmlString(), $expected->toXmlString());
+    }
 }