From 034a3528af66db0fde65686047d50e057e89e67c Mon Sep 17 00:00:00 2001
From: Christoph Strobl <cstrobl@vmware.com>
Date: Tue, 11 Oct 2022 10:31:06 +0200
Subject: [PATCH] Preserve given Id on insert.

This commit fixes an issue where an existing Id got replaced with a generated one when using MongoId annotation.

Closes: #4184
Closes: #4197
Original pull request: #4203.
---
 .../data/mongodb/core/QueryOperations.java    |  2 +-
 .../data/mongodb/core/MongoTemplateTests.java | 20 +++++++++++++++++++
 .../core/QueryOperationsUnitTests.java        |  9 +++++++++
 .../core/ReactiveMongoTemplateTests.java      | 17 ++++++++++++++++
 4 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/QueryOperations.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/QueryOperations.java
index fc712461a..5a799bcbd 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/QueryOperations.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/QueryOperations.java
@@ -272,7 +272,7 @@ class QueryOperations {
 		 */
 		<T> MappedDocument prepareId(@Nullable MongoPersistentEntity<T> entity) {
 
-			if (entity == null) {
+			if (entity == null || source.hasId()) {
 				return source;
 			}
 
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/MongoTemplateTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/MongoTemplateTests.java
index e07149c7c..7a4d78a21 100644
--- a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/MongoTemplateTests.java
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/MongoTemplateTests.java
@@ -3636,6 +3636,26 @@ public class MongoTemplateTests {
 		assertThat(target).isEqualTo(source);
 	}
 
+	@Test // GH-4184
+	void insertHonorsExistingRawId() {
+
+		RawStringId source = new RawStringId();
+		source.id = "abc";
+		source.value = "new value";
+
+		template.insert(source);
+
+		org.bson.Document result = template
+				.execute(db -> db.getCollection(template.getCollectionName(RawStringId.class))
+						.find().limit(1).cursor().next());
+
+		assertThat(result).isNotNull();
+		assertThat(result.get("_id")).isEqualTo("abc");
+
+		RawStringId target = template.findOne(query(where("id").is(source.id)), RawStringId.class);
+		assertThat(target).isEqualTo(source);
+	}
+
 	@Test // GH-4026
 	void saveShouldGenerateNewIdOfTypeIfExplicitlyDefined() {
 
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/QueryOperationsUnitTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/QueryOperationsUnitTests.java
index 0a01bed2b..2d412bab8 100644
--- a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/QueryOperationsUnitTests.java
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/QueryOperationsUnitTests.java
@@ -205,6 +205,15 @@ class QueryOperationsUnitTests {
 				});
 	}
 
+	@Test // GH-4184
+	void insertContextDoesNotOverrideExistingId() {
+
+		assertThat(queryOperations.createInsertContext(new Document("_id", "abc")).prepareId(Person.class).getDocument())//
+				.satisfies(result -> {
+					assertThat(result).isEqualTo(new Document("_id", "abc"));
+				});
+	}
+
 	static class Person {
 
 	}
diff --git a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/ReactiveMongoTemplateTests.java b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/ReactiveMongoTemplateTests.java
index 0dfe01a5d..1a4e684e2 100644
--- a/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/ReactiveMongoTemplateTests.java
+++ b/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/ReactiveMongoTemplateTests.java
@@ -218,6 +218,23 @@ public class ReactiveMongoTemplateTests {
 				}).verifyComplete();
 	}
 
+	@Test // GH-4184
+	void insertHonorsExistingRawId() {
+
+		MongoTemplateTests.RawStringId source = new MongoTemplateTests.RawStringId();
+		source.id = "abc";
+		source.value = "new value";
+
+		template.insert(source)
+				.then(template.execute(db -> Flux.from(
+						db.getCollection(template.getCollectionName(MongoTemplateTests.RawStringId.class)).find().limit(1).first()))
+						.next())
+				.as(StepVerifier::create).consumeNextWith(result -> {
+					assertThat(result).isNotNull();
+					assertThat(result.get("_id")).isEqualTo("abc");
+				});
+	}
+
 	@Test // DATAMONGO-1444
 	void insertsSimpleEntityCorrectly() {