From 2ac45f45d2eb5938667e520f0f1ca271e944c116 Mon Sep 17 00:00:00 2001
From: Giuseppe Villani <giuseppe.villani@larus-ba.it>
Date: Mon, 2 May 2022 12:21:03 +0200
Subject: [PATCH] Fixes #2699: The apoc.refactor.mergeNodes remove entities if
 a list with 2 equal nodes is passed

---
 .../java/apoc/refactor/GraphRefactoring.java  |  8 +++++---
 .../apoc/refactor/GraphRefactoringTest.java   | 19 ++++++++++++++++++-
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/core/src/main/java/apoc/refactor/GraphRefactoring.java b/core/src/main/java/apoc/refactor/GraphRefactoring.java
index 3686ea0ab4..4ff02d505e 100644
--- a/core/src/main/java/apoc/refactor/GraphRefactoring.java
+++ b/core/src/main/java/apoc/refactor/GraphRefactoring.java
@@ -278,8 +278,9 @@ private Map<Node, Node> generateStandinMap(List<List<Node>> standins) {
     public Stream<NodeResult> mergeNodes(@Name("nodes") List<Node> nodes, @Name(value = "config", defaultValue = "{}") Map<String, Object> config) {
         if (nodes == null || nodes.isEmpty()) return Stream.empty();
         RefactorConfig conf = new RefactorConfig(config);
+        Set<Node> nodesSet = new LinkedHashSet<>(nodes);
         // grab write locks upfront consistently ordered
-        nodes.stream().distinct().sorted(Comparator.comparingLong(Node::getId)).forEach(tx::acquireWriteLock);
+        nodesSet.stream().sorted(Comparator.comparingLong(Node::getId)).forEach(tx::acquireWriteLock);
 
         final Node first = nodes.get(0);
         final List<Long> existingSelfRelIds = conf.isPreservingExistingSelfRels()
@@ -288,7 +289,7 @@ public Stream<NodeResult> mergeNodes(@Name("nodes") List<Node> nodes, @Name(valu
                     .collect(Collectors.toList())
                 : Collections.emptyList();
 
-        nodes.stream().skip(1).distinct().forEach(node -> mergeNodes(node, first, conf, existingSelfRelIds));
+        nodesSet.stream().skip(1).forEach(node -> mergeNodes(node, first, conf, existingSelfRelIds));
         return Stream.of(new NodeResult(first));
     }
 
@@ -300,8 +301,9 @@ public Stream<NodeResult> mergeNodes(@Name("nodes") List<Node> nodes, @Name(valu
     @Description("apoc.refactor.mergeRelationships([rel1,rel2]) merge relationships onto first in list")
     public Stream<RelationshipResult> mergeRelationships(@Name("rels") List<Relationship> relationships, @Name(value = "config", defaultValue = "{}") Map<String, Object> config) {
         if (relationships == null || relationships.isEmpty()) return Stream.empty();
+        Set<Relationship> relationshipsSet = new LinkedHashSet<>(relationships);
         RefactorConfig conf = new RefactorConfig(config);
-        Iterator<Relationship> it = relationships.iterator();
+        Iterator<Relationship> it = relationshipsSet.iterator();
         Relationship first = it.next();
         while (it.hasNext()) {
             Relationship other = it.next();
diff --git a/core/src/test/java/apoc/refactor/GraphRefactoringTest.java b/core/src/test/java/apoc/refactor/GraphRefactoringTest.java
index 21714ada5b..cedfde3908 100644
--- a/core/src/test/java/apoc/refactor/GraphRefactoringTest.java
+++ b/core/src/test/java/apoc/refactor/GraphRefactoringTest.java
@@ -32,6 +32,7 @@
 
 import static apoc.util.MapUtil.map;
 import static apoc.util.TestUtil.testCall;
+import static apoc.util.TestUtil.testCallCount;
 import static apoc.util.TestUtil.testCallEmpty;
 import static apoc.util.TestUtil.testResult;
 import static apoc.util.Util.isSelfRel;
@@ -523,7 +524,23 @@ public void testInvertRelationship() throws Exception {
                     assertEquals(1L, rel.getProperty("a"));
                 });
     }
-
+    
+    @Test
+    public void testRefactorWithSameEntities() {
+        Node node = db.executeTransactionally("CREATE (n:SingleNode) RETURN n", emptyMap(), 
+                r -> Iterators.single(r.columnAs("n")));
+        testCall(db, "MATCH (n:SingleNode) CALL apoc.refactor.mergeNodes([n,n]) yield node return node",
+                r -> assertEquals(node, r.get("node")));
+        testCallCount(db, "MATCH (n:SingleNode) RETURN n", 1);
+
+        Relationship rel = db.executeTransactionally("CREATE (n:Start)-[r:REL_TO_MERGE]->(:End) RETURN r", emptyMap(), 
+                r -> Iterators.single(r.columnAs("r")));
+        testCall(db, "MATCH (n:Start)-[r:REL_TO_MERGE]->(:End) CALL apoc.refactor.mergeRelationships([r,r]) yield rel return rel", r -> {
+            assertEquals(rel, r.get("rel"));
+        });
+        testCallCount(db, "MATCH (n:Start)-[r:REL_TO_MERGE]->(:End) RETURN r", 1);
+    }
+    
     @Test
     public void testCollapseNode() throws Exception {
         Long id = db.executeTransactionally("CREATE (f:Foo)-[:FOO {a:1}]->(b:Bar {c:3})-[:BAR {b:2}]->(f) RETURN id(b) as id", emptyMap(), result -> Iterators.single(result.columnAs("id")));