improve performance of EqualToXmlPattern. (#2944)

removes use of DiffBuilder.ignoreComments which performs an xslt transform on the provided XML documents which is very memory intensive. now comments are ignored at read/parse time. as part of this change, the Xml utility class was also refactored to (hopefully) make it more reusable.
wiremock · Jan 30, 2025 · 9ccb1c8 · 9ccb1c8
1 parent f913265
commit 9ccb1c8
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diff --git a/src/main/java/com/github/tomakehurst/wiremock/matching/EqualToXmlPattern.java b/src/main/java/com/github/tomakehurst/wiremock/matching/EqualToXmlPattern.java
@@ -151,7 +151,6 @@ public boolean isExactMatch() {
                   .withTest(value)
                   .withComparisonController(ComparisonControllers.StopWhenDifferent)
                   .ignoreWhitespace()
-                  .ignoreComments()
                   .withDifferenceEvaluator(diffEvaluator)
                   .withNodeMatcher(new OrderInvariantNodeMatcher(ignoreOrderOfSameNode))
                   .withDocumentBuilderFactory(DOCUMENT_BUILDER_FACTORY)
@@ -188,7 +187,6 @@ public double getDistance() {
               DiffBuilder.compare(Input.from(expectedValue))
                   .withTest(value)
                   .ignoreWhitespace()
-                  .ignoreComments()
                   .withDifferenceEvaluator(diffEvaluator)
                   .withComparisonListeners(
                       (comparison, outcome) -> {
@@ -228,6 +226,7 @@ public double getDistance() {
   private static DocumentBuilderFactory newDocumentBuilderFactory() {
     DocumentBuilderFactory factory = Xml.newDocumentBuilderFactory();
     try {
+      factory.setFeature("http://apache.org/xml/features/include-comments", false);
       factory.setFeature("http://xml.org/sax/features/namespaces", true);
     } catch (ParserConfigurationException e) {
       throwUnchecked(e);

diff --git a/src/test/java/com/github/tomakehurst/wiremock/matching/EqualToXmlPatternTest.java b/src/test/java/com/github/tomakehurst/wiremock/matching/EqualToXmlPatternTest.java
@@ -568,4 +568,12 @@ void matchesIfTwoIdenticalChildNodesAreEmpty() {
     MatchResult result = pattern.match("<body><entry/><entry/></body>");
     assertTrue(result.isExactMatch());
   }
+
+  @Test
+  void matchesIfCommentsDiffer() {
+    EqualToXmlPattern pattern =
+        new EqualToXmlPattern("<body><!-- Comment --><entry/><entry/></body>", false, true);
+    MatchResult result = pattern.match("<body><entry/><entry/><!-- A different comment --></body>");
+    assertTrue(result.isExactMatch());
+  }
 }