Fix URL comparison in DeepEquals to avoid DNS resolution

Java URL.equals() performs DNS resolution which causes flaky CI failures.
Now compares URLs using toExternalForm() for reliable comparison.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: jdereg

changelog.md

@@ -1,5 +1,10 @@
 ### Revision History
 
+#### 4.90.0 (Unreleased)
+* **BUG FIX**: `DeepEquals` - URL comparison now uses string representation instead of `URL.equals()`
+  * Java's `URL.equals()` performs DNS resolution which causes flaky CI failures
+  * Now compares URLs using `toExternalForm()` for reliable, deterministic comparison
+
 #### 4.89.0 - 2026-01-31
 * **PERFORMANCE**: `FastReader.getLastSnippet()` now returns bounded 200-char context
   * Previously could return 0 to 8192 characters depending on buffer position

src/main/java/com/cedarsoftware/util/DeepEquals.java

@@ -607,6 +607,15 @@ private static boolean deepEquals(Object a, Object b, Deque<ItemsToCompare> stac
 
             // Handle primitive wrappers, String, Date, Class, UUID, URL, URI, Temporal classes, etc.
             if (Converter.isSimpleTypeConversionSupported(key1Class)) {
+                // Special handling for URL: compare by string representation to avoid DNS resolution
+                // Java's URL.equals() performs DNS lookup which causes flaky tests and CI failures
+                if (key1 instanceof URL && key2 instanceof URL) {
+                    if (!((URL) key1).toExternalForm().equals(((URL) key2).toExternalForm())) {
+                        stack.addFirst(new ItemsToCompare(key1, key2, itemsToCompare, Difference.VALUE_MISMATCH));
+                        return false;
+                    }
+                    continue;
+                }
                 if (key1 instanceof Comparable<?> && key2 instanceof Comparable<?>) {
                     try {
                         if (((Comparable)key1).compareTo(key2) != 0) {