From e0c0f3c380c8fcbad998fbac2826dc9178aec057 Mon Sep 17 00:00:00 2001
From: paulovictorv <paulovictorv@gmail.com>
Date: Mon, 6 May 2024 08:58:36 -0300
Subject: [PATCH] fix behavior when updating values where the value was
 previously null

---
 .../no2/collection/NitriteDocument.java       | 10 ++++++++--
 .../collection/CollectionUpdateTest.java      | 19 +++++++++++++++----
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/nitrite/src/main/java/org/dizitart/no2/collection/NitriteDocument.java b/nitrite/src/main/java/org/dizitart/no2/collection/NitriteDocument.java
index 314d08619..513b732f0 100644
--- a/nitrite/src/main/java/org/dizitart/no2/collection/NitriteDocument.java
+++ b/nitrite/src/main/java/org/dizitart/no2/collection/NitriteDocument.java
@@ -176,8 +176,14 @@ public Document merge(Document document) {
                     // if the value is a document, merge it recursively
                     if (containsKey(key)) {
                         // if the current document already contains the key,
-                        // then merge the embedded document
-                        get(key, Document.class).merge((Document) value);
+                        // and the value is not null, merge it
+                        Document pairs = get(key, Document.class);
+                        if (pairs != null) {
+                            pairs.merge((Document) value);
+                        } else {
+                            //otherwise, just set the value to whatever was provided
+                            put(key, value);
+                        }
                     } else {
                         // if the current document does not contain the key,
                         // then put the embedded document as it is
diff --git a/nitrite/src/test/java/org/dizitart/no2/integration/collection/CollectionUpdateTest.java b/nitrite/src/test/java/org/dizitart/no2/integration/collection/CollectionUpdateTest.java
index 4dad51555..959a2b3c0 100644
--- a/nitrite/src/test/java/org/dizitart/no2/integration/collection/CollectionUpdateTest.java
+++ b/nitrite/src/test/java/org/dizitart/no2/integration/collection/CollectionUpdateTest.java
@@ -17,10 +17,7 @@
 
 package org.dizitart.no2.integration.collection;
 
-import org.dizitart.no2.collection.Document;
-import org.dizitart.no2.collection.DocumentCursor;
-import org.dizitart.no2.collection.NitriteCollection;
-import org.dizitart.no2.collection.UpdateOptions;
+import org.dizitart.no2.collection.*;
 import org.dizitart.no2.common.WriteResult;
 import org.dizitart.no2.exceptions.NitriteIOException;
 import org.dizitart.no2.exceptions.NotIdentifiableException;
@@ -299,4 +296,18 @@ public void testIssue151() {
 
         assertEquals(coll.find(where("fruit").eq("Apple")).size(), 1);
     }
+
+    @Test
+    public void testUpdatePreviouslyNullObject() {
+        Document doc1 = createDocument().put("fruitType", null);
+        NitriteCollection coll = db.getCollection("test");
+
+        WriteResult insert = coll.insert(doc1);
+        NitriteId next = insert.iterator().next();
+        Document doc2 = createDocument().put("_id", next.getIdValue()).put("fruitType", createDocument().put("family", "citric"));
+        coll.update(doc2);
+
+        assertEquals(coll.find(where("_id").eq(next.getIdValue())).size(), 1);
+        assertNotNull(coll.find(where("_id").eq(next.getIdValue())).firstOrNull().get("fruitType"));
+    }
 }