From e1651fa7d7f3af6463c19b40608ac9b1ed3b1207 Mon Sep 17 00:00:00 2001
From: Christoph Strobl <cstrobl@vmware.com>
Date: Thu, 1 Jul 2021 08:14:57 +0200
Subject: [PATCH 1/2] Prepare issue branch.

---
 pom.xml                                  | 2 +-
 spring-data-mongodb-benchmarks/pom.xml   | 2 +-
 spring-data-mongodb-distribution/pom.xml | 2 +-
 spring-data-mongodb/pom.xml              | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/pom.xml b/pom.xml
index a6d5da9170..d413b40ae2 100644
--- a/pom.xml
+++ b/pom.xml
@@ -5,7 +5,7 @@
 
 	<groupId>org.springframework.data</groupId>
 	<artifactId>spring-data-mongodb-parent</artifactId>
-	<version>3.3.0-SNAPSHOT</version>
+	<version>3.3.0-GH-3686-SNAPSHOT</version>
 	<packaging>pom</packaging>
 
 	<name>Spring Data MongoDB</name>
diff --git a/spring-data-mongodb-benchmarks/pom.xml b/spring-data-mongodb-benchmarks/pom.xml
index 0033bd11d5..47df593531 100644
--- a/spring-data-mongodb-benchmarks/pom.xml
+++ b/spring-data-mongodb-benchmarks/pom.xml
@@ -7,7 +7,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>3.3.0-SNAPSHOT</version>
+		<version>3.3.0-GH-3686-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/spring-data-mongodb-distribution/pom.xml b/spring-data-mongodb-distribution/pom.xml
index f62c8dc7f4..a4706d3f8a 100644
--- a/spring-data-mongodb-distribution/pom.xml
+++ b/spring-data-mongodb-distribution/pom.xml
@@ -14,7 +14,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>3.3.0-SNAPSHOT</version>
+		<version>3.3.0-GH-3686-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 
diff --git a/spring-data-mongodb/pom.xml b/spring-data-mongodb/pom.xml
index 1f157e75bc..4df87665d8 100644
--- a/spring-data-mongodb/pom.xml
+++ b/spring-data-mongodb/pom.xml
@@ -11,7 +11,7 @@
 	<parent>
 		<groupId>org.springframework.data</groupId>
 		<artifactId>spring-data-mongodb-parent</artifactId>
-		<version>3.3.0-SNAPSHOT</version>
+		<version>3.3.0-GH-3686-SNAPSHOT</version>
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 

From 5197834839ad92ad98c6012079dbc7874f665196 Mon Sep 17 00:00:00 2001
From: Christoph Strobl <cstrobl@vmware.com>
Date: Thu, 1 Jul 2021 08:50:24 +0200
Subject: [PATCH 2/2] Fix NPE when reading/mapping null value inside
 collection.

Closes: #3686
---
 .../core/convert/MappingMongoConverter.java   |  8 +++-
 .../MappingMongoConverterUnitTests.java       | 39 +++++++++++++++++++
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java
index 732e8c9a51..14d6ddda08 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java
@@ -2006,12 +2006,16 @@ protected static class ConversionContext {
 		/**
 		 * Converts a source object into {@link TypeInformation target}.
 		 *
-		 * @param source must not be {@literal null}.
+		 * @param source can be {@literal null}.
 		 * @param typeHint must not be {@literal null}.
 		 * @return the converted object.
 		 */
 		@SuppressWarnings("unchecked")
-		public <S extends Object> S convert(Object source, TypeInformation<? extends S> typeHint) {
+		public <S extends Object> S convert(@Nullable Object source, TypeInformation<? extends S> typeHint) {
+
+			if(source == null) {
+				return null;
+			}
 
 			Assert.notNull(typeHint, "TypeInformation must not be null");
 
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/MappingMongoConverterUnitTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/MappingMongoConverterUnitTests.java
index 0361571414..c8e2fec155 100644
--- a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/MappingMongoConverterUnitTests.java
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/MappingMongoConverterUnitTests.java
@@ -2532,6 +2532,41 @@ void shouldWriteNullPropertyCorrectly() {
 		assertThat(document).containsEntry("writeAlwaysPerson", null).doesNotContainKey("writeNonNullPerson");
 	}
 
+	@Test // GH-3686
+	void readsCollectionContainingNullValue() {
+
+		org.bson.Document source = new org.bson.Document("items", Arrays.asList(new org.bson.Document("itemKey", "i1"), null, new org.bson.Document("itemKey", "i3")));
+
+		Order target = converter.read(Order.class, source);
+
+		assertThat(target.items)
+				.map(it -> it != null ? it.itemKey : null)
+				.containsExactly("i1", null, "i3");
+	}
+
+	@Test // GH-3686
+	void readsArrayContainingNullValue() {
+
+		org.bson.Document source = new org.bson.Document("arrayOfStrings", Arrays.asList("i1", null, "i3"));
+
+		WithArrays target = converter.read(WithArrays.class, source);
+
+		assertThat(target.arrayOfStrings).containsExactly("i1", null, "i3");
+	}
+
+	@Test // GH-3686
+	void readsMapContainingNullValue() {
+
+		org.bson.Document source = new org.bson.Document("mapOfObjects", new org.bson.Document("item1", "i1").append("item2", null).append("item3", "i3"));
+
+		ClassWithMapProperty target = converter.read(ClassWithMapProperty.class, source);
+
+		assertThat(target.mapOfObjects)
+				.containsEntry("item1", "i1")
+				.containsEntry("item2", null)
+				.containsEntry("item3", "i3");
+	}
+
 	static class GenericType<T> {
 		T content;
 	}
@@ -2893,6 +2928,10 @@ static class WithArrayInConstructor {
 
 	}
 
+	static class WithArrays {
+		String[] arrayOfStrings;
+	}
+
 	// DATAMONGO-1898
 
 	// DATACMNS-1278