refactor: Use identity checks instead of DiffNode.getID

Author: ibbem

src/main/java/org/variantsync/diffdetective/variation/diff/DiffTree.java

@@ -359,7 +359,7 @@ private enum VisitStatus {
             ALL_PATHS_END_AT_ROOT,
             NOT_ALL_PATHS_END_AT_ROOT
         }
-        private final Map<Integer, VisitStatus> cache = new HashMap<>();
+        private final Map<DiffNode, VisitStatus> cache = new HashMap<>();
         private final DiffNode root;
 
         private AllPathsEndAtRoot(final DiffNode root) {
@@ -375,11 +375,10 @@ public boolean test(final DiffNode d) {
                 return true;
             }
 
-            final int id = d.getID();
-            return switch (cache.getOrDefault(id, VisitStatus.STRANGER)) {
+            return switch (cache.getOrDefault(d, VisitStatus.STRANGER)) {
                 case STRANGER -> {
                     // The stranger is now known.
-                    cache.putIfAbsent(id, VisitStatus.VISITED);
+                    cache.putIfAbsent(d, VisitStatus.VISITED);
 
                     final DiffNode b = d.getParent(BEFORE);
                     final DiffNode a = d.getParent(AFTER);
@@ -397,7 +396,7 @@ public boolean test(final DiffNode d) {
                     }
 
                     // Now we also know the result for the stranger.
-                    cache.put(id, result ? VisitStatus.ALL_PATHS_END_AT_ROOT : VisitStatus.NOT_ALL_PATHS_END_AT_ROOT);
+                    cache.put(d, result ? VisitStatus.ALL_PATHS_END_AT_ROOT : VisitStatus.NOT_ALL_PATHS_END_AT_ROOT);
                     yield result;
                 }
                 // We detected a cycle because we visited a node but did not determine its value yet!

src/main/java/org/variantsync/diffdetective/variation/diff/traverse/DiffTreeTraversal.java

@@ -22,7 +22,7 @@
  * @author Paul Bittner
  */
 public class DiffTreeTraversal {
-    private final Set<Integer> visited;
+    private final Set<DiffNode> visited;
     private final DiffTreeVisitor visitor;
 
     private DiffTreeTraversal(final DiffTreeVisitor visitor) {
@@ -86,6 +86,6 @@ public void visitChildrenOf(final DiffNode subtree) {
      *         False if the node was already marked visited.
      */
     private boolean markAsVisited(final DiffNode node) {
-        return visited.add(node.getID());
+        return visited.add(node);
     }
 }