SERVER-67400 Introduce a CollectionPlacement component of the collection version

30 files changed, 202 insertions, 268 deletions

diff --git a/src/mongo/db/pipeline/dispatch_shard_pipeline_test.cpp b/src/mongo/db/pipeline/dispatch_shard_pipeline_test.cpp
index 069a7e2f0b2..effa178fc32 100644
--- a/src/mongo/db/pipeline/dispatch_shard_pipeline_test.cpp
+++ b/src/mongo/db/pipeline/dispatch_shard_pipeline_test.cpp
@@ -175,7 +175,7 @@ TEST_F(DispatchShardPipelineTest, DispatchShardPipelineDoesNotRetryOnStaleConfig
         OID epoch{OID::gen()};
         Timestamp timestamp{1, 0};
         return createErrorCursorResponse({StaleConfigInfo(kTestAggregateNss,
-                                                          ChunkVersion(1, 0, epoch, timestamp),
+                                                          ChunkVersion({epoch, timestamp}, {1, 0}),
                                                           boost::none,
                                                           ShardId{"0"}),
                                           "Mock error: shard version mismatch"});
@@ -218,7 +218,7 @@ TEST_F(DispatchShardPipelineTest, WrappedDispatchDoesRetryOnStaleConfigError) {
     // namespace, then mock out a successful response.
     onCommand([&](const executor::RemoteCommandRequest& request) {
         return createErrorCursorResponse({StaleConfigInfo(kTestAggregateNss,
-                                                          ChunkVersion(2, 0, epoch, timestamp),
+                                                          ChunkVersion({epoch, timestamp}, {2, 0}),
                                                           boost::none,
                                                           ShardId{"0"}),
                                           "Mock error: shard version mismatch"});
@@ -227,7 +227,7 @@ TEST_F(DispatchShardPipelineTest, WrappedDispatchDoesRetryOnStaleConfigError) {
     // Mock the expected config server queries.
     const ShardKeyPattern shardKeyPattern(BSON("_id" << 1));
 
-    ChunkVersion version(2, 0, epoch, timestamp);
+    ChunkVersion version({epoch, timestamp}, {2, 0});
 
     ChunkType chunk1(
         uuid, {shardKeyPattern.getKeyPattern().globalMin(), BSON("_id" << 0)}, version, {"0"});
diff --git a/src/mongo/db/pipeline/process_interface/mongos_process_interface_test.cpp b/src/mongo/db/pipeline/process_interface/mongos_process_interface_test.cpp
index 83b35a0c9fc..30de3fbfb1f 100644
--- a/src/mongo/db/pipeline/process_interface/mongos_process_interface_test.cpp
+++ b/src/mongo/db/pipeline/process_interface/mongos_process_interface_test.cpp
@@ -27,8 +27,6 @@
  *    it in the license file.
  */
 
-#include "mongo/platform/basic.h"
-
 #include "mongo/db/pipeline/aggregation_context_fixture.h"
 #include "mongo/db/pipeline/process_interface/mongos_process_interface.h"
 #include "mongo/unittest/unittest.h"
@@ -63,7 +61,7 @@ public:
 TEST_F(MongosProcessInterfaceTest, FailsToEnsureFieldsUniqueIfTargetCollectionVersionIsSpecified) {
     auto expCtx = getExpCtx();
     auto targetCollectionVersion =
-        boost::make_optional(ChunkVersion(0, 0, OID::gen(), Timestamp(1, 1)));
+        boost::make_optional(ChunkVersion({OID::gen(), Timestamp(1, 1)}, {0, 0}));
     auto processInterface = makeProcessInterface();
 
     ASSERT_THROWS_CODE(processInterface->ensureFieldsUniqueOrResolveDocumentKey(
diff --git a/src/mongo/db/pipeline/resharding_initial_split_policy_test.cpp b/src/mongo/db/pipeline/resharding_initial_split_policy_test.cpp
index bc17e9d0133..2df79a991d4 100644
--- a/src/mongo/db/pipeline/resharding_initial_split_policy_test.cpp
+++ b/src/mongo/db/pipeline/resharding_initial_split_policy_test.cpp
@@ -27,9 +27,6 @@
  *    it in the license file.
  */
 
-
-#include "mongo/platform/basic.h"
-
 #include "mongo/db/catalog/collection_catalog.h"
 #include "mongo/db/pipeline/document_source_mock.h"
 #include "mongo/db/pipeline/sharded_agg_helpers.h"
@@ -39,7 +36,6 @@
 
 #define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kTest
 
-
 namespace mongo {
 namespace {
 
diff --git a/src/mongo/db/s/balancer/balancer_defragmentation_policy_test.cpp b/src/mongo/db/s/balancer/balancer_defragmentation_policy_test.cpp
index c42f7e86cd7..d1f431b4082 100644
--- a/src/mongo/db/s/balancer/balancer_defragmentation_policy_test.cpp
+++ b/src/mongo/db/s/balancer/balancer_defragmentation_policy_test.cpp
@@ -47,7 +47,7 @@ protected:
     const ShardId kShardId1 = ShardId("shard1");
     const ShardId kShardId2 = ShardId("shard2");
     const ShardId kShardId3 = ShardId("shard3");
-    const ChunkVersion kCollectionVersion = ChunkVersion(1, 1, OID::gen(), Timestamp(10));
+    const ChunkVersion kCollectionVersion = ChunkVersion({OID::gen(), Timestamp(10)}, {1, 1});
     const KeyPattern kShardKeyPattern = KeyPattern(BSON("x" << 1));
     const BSONObj kKeyAtMin = BSONObjBuilder().appendMinKey("x").obj();
     const BSONObj kKeyAtZero = BSON("x" << 0);
@@ -494,7 +494,8 @@ TEST_F(BalancerDefragmentationPolicyTest, TestPhaseOneAllConsecutive) {
         ChunkType chunk(
             kUuid,
             ChunkRange(minKey, maxKey),
-            ChunkVersion(1, i, kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()),
+            ChunkVersion({kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()},
+                         {1, uint32_t(i)}),
             kShardId0);
         chunkList.push_back(chunk);
     }
@@ -504,7 +505,8 @@ TEST_F(BalancerDefragmentationPolicyTest, TestPhaseOneAllConsecutive) {
         ChunkType chunk(
             kUuid,
             ChunkRange(minKey, maxKey),
-            ChunkVersion(1, i, kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()),
+            ChunkVersion({kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()},
+                         {1, uint32_t(i)}),
             kShardId1);
         chunkList.push_back(chunk);
     }
@@ -543,7 +545,8 @@ TEST_F(BalancerDefragmentationPolicyTest, PhaseOneNotConsecutive) {
         ChunkType chunk(
             kUuid,
             ChunkRange(minKey, maxKey),
-            ChunkVersion(1, i, kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()),
+            ChunkVersion({kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()},
+                         {1, uint32_t(i)}),
             chosenShard);
         chunkList.push_back(chunk);
     }
@@ -620,13 +623,13 @@ TEST_F(BalancerDefragmentationPolicyTest, TestPhaseTwoChunkCanBeMovedAndMergedWi
     ChunkType biggestChunk(
         kUuid,
         ChunkRange(kKeyAtMin, kKeyAtZero),
-        ChunkVersion(1, 0, kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()),
+        ChunkVersion({kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()}, {1, 0}),
         kShardId0);
     biggestChunk.setEstimatedSizeBytes(2048);
     ChunkType smallestChunk(
         kUuid,
         ChunkRange(kKeyAtZero, kKeyAtMax),
-        ChunkVersion(1, 1, kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()),
+        ChunkVersion({kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()}, {1, 1}),
         kShardId1);
     smallestChunk.setEstimatedSizeBytes(1024);
 
@@ -682,42 +685,42 @@ TEST_F(BalancerDefragmentationPolicyTest,
     ChunkType firstChunkOnShard0(
         kUuid,
         ChunkRange(kKeyAtMin, kKeyAtZero),
-        ChunkVersion(1, 0, kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()),
+        ChunkVersion({kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()}, {1, 0}),
         kShardId0);
     firstChunkOnShard0.setEstimatedSizeBytes(1);
 
     ChunkType firstChunkOnShard1(
         kUuid,
         ChunkRange(kKeyAtZero, kKeyAtTen),
-        ChunkVersion(1, 1, kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()),
+        ChunkVersion({kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()}, {1, 1}),
         kShardId1);
     firstChunkOnShard1.setEstimatedSizeBytes(1);
 
     ChunkType chunkOnShard2(
         kUuid,
         ChunkRange(kKeyAtTen, kKeyAtTwenty),
-        ChunkVersion(1, 2, kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()),
+        ChunkVersion({kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()}, {1, 2}),
         kShardId2);
     chunkOnShard2.setEstimatedSizeBytes(1);
 
     ChunkType chunkOnShard3(
         kUuid,
         ChunkRange(kKeyAtTwenty, kKeyAtThirty),
-        ChunkVersion(1, 3, kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()),
+        ChunkVersion({kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()}, {1, 3}),
         kShardId3);
     chunkOnShard3.setEstimatedSizeBytes(1);
 
     ChunkType secondChunkOnShard0(
         kUuid,
         ChunkRange(kKeyAtThirty, kKeyAtForty),
-        ChunkVersion(1, 4, kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()),
+        ChunkVersion({kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()}, {1, 4}),
         kShardId0);
     secondChunkOnShard0.setEstimatedSizeBytes(1);
 
     ChunkType secondChunkOnShard1(
         kUuid,
         ChunkRange(kKeyAtForty, kKeyAtMax),
-        ChunkVersion(1, 5, kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()),
+        ChunkVersion({kCollectionVersion.epoch(), kCollectionVersion.getTimestamp()}, {1, 5}),
         kShardId1);
     secondChunkOnShard1.setEstimatedSizeBytes(1);
 
diff --git a/src/mongo/db/s/balancer/balancer_policy_test.cpp b/src/mongo/db/s/balancer/balancer_policy_test.cpp
index fb98d610b00..be3532fee56 100644
--- a/src/mongo/db/s/balancer/balancer_policy_test.cpp
+++ b/src/mongo/db/s/balancer/balancer_policy_test.cpp
@@ -27,9 +27,6 @@
  *    it in the license file.
  */
 
-
-#include "mongo/platform/basic.h"
-
 #include "mongo/db/keypattern.h"
 #include "mongo/db/s/balancer/balancer_policy.h"
 #include "mongo/platform/random.h"
@@ -79,7 +76,7 @@ std::pair<ShardStatisticsVector, ShardToChunksMap> generateCluster(
 
     int64_t currentChunk = 0;
 
-    ChunkVersion chunkVersion(1, 0, OID::gen(), Timestamp(1, 1));
+    ChunkVersion chunkVersion({OID::gen(), Timestamp(1, 1)}, {1, 0});
     const UUID uuid = UUID::gen();
 
     const KeyPattern shardKeyPattern(BSON("x" << 1));
diff --git a/src/mongo/db/s/collection_sharding_runtime_test.cpp b/src/mongo/db/s/collection_sharding_runtime_test.cpp
index dcee5b73ac0..c6985aa5742 100644
--- a/src/mongo/db/s/collection_sharding_runtime_test.cpp
+++ b/src/mongo/db/s/collection_sharding_runtime_test.cpp
@@ -27,8 +27,6 @@
  *    it in the license file.
  */
 
-#include "mongo/platform/basic.h"
-
 #include "boost/optional/optional_io.hpp"
 #include "mongo/db/catalog/create_collection.h"
 #include "mongo/db/catalog_raii.h"
@@ -63,7 +61,7 @@ protected:
         const Timestamp timestamp(1, 1);
         auto range = ChunkRange(BSON(kShardKey << MINKEY), BSON(kShardKey << MAXKEY));
         auto chunk = ChunkType(
-            uuid, std::move(range), ChunkVersion(1, 0, epoch, timestamp), ShardId("other"));
+            uuid, std::move(range), ChunkVersion({epoch, timestamp}, {1, 0}), ShardId("other"));
         ChunkManager cm(ShardId("0"),
                         DatabaseVersion(UUID::gen(), timestamp),
                         makeStandaloneRoutingTableHistory(
@@ -218,8 +216,8 @@ TEST_F(CollectionShardingRuntimeTest, ReturnUnshardedMetadataInServerlessMode) {
     ScopedSetShardRole scopedSetShardRole2{
         opCtx,
         NamespaceString::kLogicalSessionsNamespace,
-        ChunkVersion(1, 0, OID::gen(), Timestamp(1, 1)), /* shardVersion */
-        boost::none                                      /* databaseVersion */
+        ChunkVersion({OID::gen(), Timestamp(1, 1)}, {1, 0}), /* shardVersion */
+        boost::none                                          /* databaseVersion */
     };
 
     CollectionShardingRuntime csrLogicalSession(
@@ -324,11 +322,11 @@ public:
                                         const Timestamp& timestamp) {
         auto range1 = ChunkRange(BSON(kShardKey << MINKEY), BSON(kShardKey << 5));
         ChunkType chunk1(
-            uuid, range1, ChunkVersion(1, 0, epoch, timestamp), kShardList[0].getName());
+            uuid, range1, ChunkVersion({epoch, timestamp}, {1, 0}), kShardList[0].getName());
 
         auto range2 = ChunkRange(BSON(kShardKey << 5), BSON(kShardKey << MAXKEY));
         ChunkType chunk2(
-            uuid, range2, ChunkVersion(1, 1, epoch, timestamp), kShardList[0].getName());
+            uuid, range2, ChunkVersion({epoch, timestamp}, {1, 1}), kShardList[0].getName());
 
         return {chunk1, chunk2};
     }
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_bump_collection_version_and_change_metadata_test.cpp b/src/mongo/db/s/config/sharding_catalog_manager_bump_collection_version_and_change_metadata_test.cpp
index a4abd0ff45b..fbb502f933b 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_bump_collection_version_and_change_metadata_test.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_bump_collection_version_and_change_metadata_test.cpp
@@ -27,8 +27,6 @@
  *    it in the license file.
  */
 
-#include "mongo/platform/basic.h"
-
 #include "mongo/db/concurrency/exception_util.h"
 #include "mongo/db/dbdirectclient.h"
 #include "mongo/db/logical_session_cache_noop.h"
@@ -43,7 +41,6 @@
 
 #define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kTest
 
-
 namespace mongo {
 namespace {
 
@@ -121,17 +118,17 @@ TEST_F(ShardingCatalogManagerBumpCollectionVersionAndChangeMetadataTest,
     const auto collUUID = UUID::gen();
 
     const auto shard0Chunk0 = generateChunkType(collUUID,
-                                                ChunkVersion(10, 1, collEpoch, collTimestamp),
+                                                ChunkVersion({collEpoch, collTimestamp}, {10, 1}),
                                                 kShard0.getName(),
                                                 BSON("a" << 1),
                                                 BSON("a" << 10));
     const auto shard0Chunk1 = generateChunkType(collUUID,
-                                                ChunkVersion(11, 2, collEpoch, collTimestamp),
+                                                ChunkVersion({collEpoch, collTimestamp}, {11, 2}),
                                                 kShard0.getName(),
                                                 BSON("a" << 11),
                                                 BSON("a" << 20));
     const auto shard1Chunk0 = generateChunkType(collUUID,
-                                                ChunkVersion(8, 1, collEpoch, collTimestamp),
+                                                ChunkVersion({collEpoch, collTimestamp}, {8, 1}),
                                                 kShard1.getName(),
                                                 BSON("a" << 21),
                                                 BSON("a" << 100));
@@ -157,7 +154,7 @@ TEST_F(ShardingCatalogManagerBumpCollectionVersionAndChangeMetadataTest, NoChunk
     const auto collUUID = UUID::gen();
 
     const auto shard0Chunk0 = generateChunkType(collUUID,
-                                                ChunkVersion(10, 1, collEpoch, collTimestamp),
+                                                ChunkVersion({collEpoch, collTimestamp}, {10, 1}),
                                                 kShard0.getName(),
                                                 BSON("a" << 1),
                                                 BSON("a" << 10));
@@ -182,12 +179,12 @@ TEST_F(ShardingCatalogManagerBumpCollectionVersionAndChangeMetadataTest,
     const auto collUUID = UUID::gen();
 
     const auto shard0Chunk0 = generateChunkType(collUUID,
-                                                ChunkVersion(10, 1, collEpoch, collTimestamp),
+                                                ChunkVersion({collEpoch, collTimestamp}, {10, 1}),
                                                 kShard0.getName(),
                                                 BSON("a" << 1),
                                                 BSON("a" << 10));
     const auto shard1Chunk0 = generateChunkType(collUUID,
-                                                ChunkVersion(11, 2, collEpoch, collTimestamp),
+                                                ChunkVersion({collEpoch, collTimestamp}, {11, 2}),
                                                 kShard1.getName(),
                                                 BSON("a" << 11),
                                                 BSON("a" << 20));
@@ -244,12 +241,12 @@ TEST_F(ShardingCatalogManagerBumpCollectionVersionAndChangeMetadataTest,
     const auto collUUID = UUID::gen();
 
     const auto shard0Chunk0 = generateChunkType(collUUID,
-                                                ChunkVersion(10, 1, collEpoch, collTimestamp),
+                                                ChunkVersion({collEpoch, collTimestamp}, {10, 1}),
                                                 kShard0.getName(),
                                                 BSON("a" << 1),
                                                 BSON("a" << 10));
     const auto shard1Chunk0 = generateChunkType(collUUID,
-                                                ChunkVersion(11, 2, collEpoch, collTimestamp),
+                                                ChunkVersion({collEpoch, collTimestamp}, {11, 2}),
                                                 kShard1.getName(),
                                                 BSON("a" << 11),
                                                 BSON("a" << 20));
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_chunk_operations.cpp b/src/mongo/db/s/config/sharding_catalog_manager_chunk_operations.cpp
index 83daf277078..f461f1ae0a5 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_chunk_operations.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_chunk_operations.cpp
@@ -27,9 +27,6 @@
  *    it in the license file.
  */
 
-
-#include "mongo/platform/basic.h"
-
 #include "mongo/db/s/config/sharding_catalog_manager.h"
 
 #include "mongo/base/status_with.h"
@@ -67,7 +64,6 @@
 
 #define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kSharding
 
-
 namespace mongo {
 namespace {
 
@@ -268,7 +264,8 @@ ChunkVersion getShardVersion(OperationContext* opCtx,
         if (swDonorShardVersion.getStatus().code() == 50577) {
             // The query to find 'nss' chunks belonging to the donor shard didn't return any chunks,
             // meaning the last chunk for fromShard was donated. Gracefully handle the error.
-            return ChunkVersion(0, 0, collectionVersion.epoch(), collectionVersion.getTimestamp());
+            return ChunkVersion({collectionVersion.epoch(), collectionVersion.getTimestamp()},
+                                {0, 0});
         } else {
             // Bubble up any other error
             uassertStatusOK(swDonorShardVersion);
@@ -391,10 +388,9 @@ void ShardingCatalogManager::bumpMajorVersionOneChunkPerShard(
     TxnNumber txnNumber,
     const std::vector<ShardId>& shardIds) {
     auto curCollectionVersion = uassertStatusOK(getCollectionVersion(opCtx, nss));
-    ChunkVersion targetChunkVersion(curCollectionVersion.majorVersion() + 1,
-                                    0,
-                                    curCollectionVersion.epoch(),
-                                    curCollectionVersion.getTimestamp());
+    ChunkVersion targetChunkVersion(
+        {curCollectionVersion.epoch(), curCollectionVersion.getTimestamp()},
+        {curCollectionVersion.majorVersion() + 1, 0});
 
     auto const configShard = Grid::get(opCtx)->shardRegistry()->getConfigShard();
     auto findCollResponse = uassertStatusOK(
@@ -1127,10 +1123,9 @@ StatusWith<BSONObj> ShardingCatalogManager::commitChunkMigration(
     newMigratedChunk->setMin(migratedChunk.getMin());
     newMigratedChunk->setMax(migratedChunk.getMax());
     newMigratedChunk->setShard(toShard);
-    newMigratedChunk->setVersion(ChunkVersion(currentCollectionVersion.majorVersion() + 1,
-                                              minVersionIncrement++,
-                                              currentCollectionVersion.epoch(),
-                                              currentCollectionVersion.getTimestamp()));
+    newMigratedChunk->setVersion(
+        ChunkVersion({currentCollectionVersion.epoch(), currentCollectionVersion.getTimestamp()},
+                     {currentCollectionVersion.majorVersion() + 1, minVersionIncrement++}));
 
     // Copy the complete history.
     auto newHistory = currentChunk.getHistory();
@@ -1186,10 +1181,9 @@ StatusWith<BSONObj> ShardingCatalogManager::commitChunkMigration(
             ChunkType leftSplitChunk = currentChunk;
             leftSplitChunk.setName(OID::gen());
             leftSplitChunk.setMax(movedChunkMin);
-            leftSplitChunk.setVersion(ChunkVersion(movedChunkVersion.majorVersion(),
-                                                   minVersionIncrement++,
-                                                   movedChunkVersion.epoch(),
-                                                   movedChunkVersion.getTimestamp()));
+            leftSplitChunk.setVersion(
+                ChunkVersion({movedChunkVersion.epoch(), movedChunkVersion.getTimestamp()},
+                             {movedChunkVersion.majorVersion(), minVersionIncrement++}));
             newSplitChunks->emplace_back(std::move(leftSplitChunk));
         }
 
@@ -1199,10 +1193,9 @@ StatusWith<BSONObj> ShardingCatalogManager::commitChunkMigration(
             ChunkType rightSplitChunk = currentChunk;
             rightSplitChunk.setName(OID::gen());
             rightSplitChunk.setMin(movedChunkMax);
-            rightSplitChunk.setVersion(ChunkVersion(movedChunkVersion.majorVersion(),
-                                                    minVersionIncrement++,
-                                                    movedChunkVersion.epoch(),
-                                                    movedChunkVersion.getTimestamp()));
+            rightSplitChunk.setVersion(
+                ChunkVersion({movedChunkVersion.epoch(), movedChunkVersion.getTimestamp()},
+                             {movedChunkVersion.majorVersion(), minVersionIncrement++}));
             newSplitChunks->emplace_back(std::move(rightSplitChunk));
         }
     }
@@ -1218,10 +1211,9 @@ StatusWith<BSONObj> ShardingCatalogManager::commitChunkMigration(
 
         newControlChunk = std::make_shared<ChunkType>(origControlChunk);
         // Setting control chunk's minor version to 1 on the donor shard.
-        newControlChunk->setVersion(ChunkVersion(currentCollectionVersion.majorVersion() + 1,
-                                                 minVersionIncrement++,
-                                                 currentCollectionVersion.epoch(),
-                                                 currentCollectionVersion.getTimestamp()));
+        newControlChunk->setVersion(ChunkVersion(
+            {currentCollectionVersion.epoch(), currentCollectionVersion.getTimestamp()},
+            {currentCollectionVersion.majorVersion() + 1, minVersionIncrement++}));
     }
 
     _commitChunkMigrationInTransaction(
@@ -1232,7 +1224,7 @@ StatusWith<BSONObj> ShardingCatalogManager::commitChunkMigration(
         // We migrated the last chunk from the donor shard.
         newMigratedChunk->getVersion().serializeToBSON(kCollectionVersionField, &response);
         const ChunkVersion donorShardVersion(
-            0, 0, currentCollectionVersion.epoch(), currentCollectionVersion.getTimestamp());
+            {currentCollectionVersion.epoch(), currentCollectionVersion.getTimestamp()}, {0, 0});
         donorShardVersion.serializeToBSON(ChunkVersion::kShardVersionField, &response);
     } else {
         newControlChunk->getVersion().serializeToBSON(kCollectionVersionField, &response);
@@ -1349,8 +1341,8 @@ void ShardingCatalogManager::upgradeChunksHistory(OperationContext* opCtx,
     }();
 
     // Bump the major version in order to be guaranteed to trigger refresh on every shard
-    ChunkVersion newCollectionVersion(
-        collVersion.majorVersion() + 1, 0, collVersion.epoch(), collVersion.getTimestamp());
+    ChunkVersion newCollectionVersion({collVersion.epoch(), collVersion.getTimestamp()},
+                                      {collVersion.majorVersion() + 1, 0});
     std::set<ShardId> changedShardIds;
     for (const auto& chunk : allChunksVector) {
         auto upgradeChunk = uassertStatusOK(
@@ -1491,10 +1483,9 @@ void ShardingCatalogManager::clearJumboFlag(OperationContext* opCtx,
                           << chunk.toString() << ").",
             currentCollectionVersion.epoch() == collectionEpoch);
 
-    ChunkVersion newVersion(currentCollectionVersion.majorVersion() + 1,
-                            0,
-                            currentCollectionVersion.epoch(),
-                            currentCollectionVersion.getTimestamp());
+    ChunkVersion newVersion(
+        {currentCollectionVersion.epoch(), currentCollectionVersion.getTimestamp()},
+        {currentCollectionVersion.majorVersion() + 1, 0});
 
     BSONObj chunkQuery(BSON(ChunkType::min(chunk.getMin())
                             << ChunkType::max(chunk.getMax()) << ChunkType::collectionUUID
@@ -1653,8 +1644,8 @@ void ShardingCatalogManager::ensureChunkVersionIsGreaterThan(OperationContext* o
     // Generate a new version for the chunk by incrementing the collectionVersion's major
     // version.
     auto newChunk = matchingChunk;
-    newChunk.setVersion(ChunkVersion(
-        highestChunk.getVersion().majorVersion() + 1, 0, coll.getEpoch(), coll.getTimestamp()));
+    newChunk.setVersion(ChunkVersion({coll.getEpoch(), coll.getTimestamp()},
+                                     {highestChunk.getVersion().majorVersion() + 1, 0}));
 
     // Update the chunk, if it still exists, to have the bumped version.
     earlyReturnBeforeDoingWriteGuard.dismiss();
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_commit_chunk_migration_test.cpp b/src/mongo/db/s/config/sharding_catalog_manager_commit_chunk_migration_test.cpp
index 8452740c17e..fc8a55a9635 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_commit_chunk_migration_test.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_commit_chunk_migration_test.cpp
@@ -27,8 +27,6 @@
  *    it in the license file.
  */
 
-#include "mongo/platform/basic.h"
-
 #include "mongo/bson/bsonobj.h"
 #include "mongo/bson/bsonobjbuilder.h"
 #include "mongo/client/read_preference.h"
@@ -49,7 +47,6 @@
 
 #define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kTest
 
-
 namespace mongo {
 namespace {
 
@@ -104,7 +101,7 @@ TEST_F(CommitChunkMigrate, ChunksUpdatedCorrectly) {
 
     ChunkType migratedChunk, controlChunk;
     {
-        ChunkVersion origVersion(12, 7, collEpoch, collTimestamp);
+        ChunkVersion origVersion({collEpoch, collTimestamp}, {12, 7});
 
         migratedChunk.setName(OID::gen());
         migratedChunk.setCollectionUUID(collUUID);
@@ -141,10 +138,9 @@ TEST_F(CommitChunkMigrate, ChunksUpdatedCorrectly) {
 
     // Verify the versions returned match expected values.
     auto mver = ChunkVersion::parse(versions["shardVersion"]);
-    ASSERT_EQ(ChunkVersion(migratedChunk.getVersion().majorVersion() + 1,
-                           1,
-                           migratedChunk.getVersion().epoch(),
-                           migratedChunk.getVersion().getTimestamp()),
+    ASSERT_EQ(ChunkVersion(
+                  {migratedChunk.getVersion().epoch(), migratedChunk.getVersion().getTimestamp()},
+                  {migratedChunk.getVersion().majorVersion() + 1, 1}),
               mver);
 
     // Verify that a collection version is returned
@@ -188,8 +184,8 @@ TEST_F(CommitChunkMigrate, ChunksUpdatedCorrectlyWithoutControlChunk) {
 
     setupShards({shard0, shard1});
 
-    int origMajorVersion = 15;
-    auto const origVersion = ChunkVersion(origMajorVersion, 4, collEpoch, collTimestamp);
+    uint32_t origMajorVersion = 15;
+    auto const origVersion = ChunkVersion({collEpoch, collTimestamp}, {origMajorVersion, 4});
 
     ChunkType chunk0;
     chunk0.setName(OID::gen());
@@ -223,11 +219,11 @@ TEST_F(CommitChunkMigrate, ChunksUpdatedCorrectlyWithoutControlChunk) {
     // Verify the version returned matches expected value.
     BSONObj versions = resultBSON.getValue();
     auto mver = ChunkVersion::parse(versions["shardVersion"]);
-    ASSERT_EQ(ChunkVersion(0, 0, origVersion.epoch(), origVersion.getTimestamp()), mver);
+    ASSERT_EQ(ChunkVersion({origVersion.epoch(), origVersion.getTimestamp()}, {0, 0}), mver);
 
     // Verify that a collection version is returned
     auto cver = ChunkVersion::parse(versions["collectionVersion"]);
-    ASSERT_EQ(ChunkVersion(origMajorVersion + 1, 0, collEpoch, collTimestamp), cver);
+    ASSERT_EQ(ChunkVersion({collEpoch, collTimestamp}, {origMajorVersion + 1, 0}), cver);
 
     // Verify the chunk ended up in the right shard.
     auto chunkDoc0 =
@@ -253,8 +249,8 @@ TEST_F(CommitChunkMigrate, CheckCorrectOpsCommandNoCtlTrimHistory) {
 
     setupShards({shard0, shard1});
 
-    int origMajorVersion = 15;
-    auto const origVersion = ChunkVersion(origMajorVersion, 4, collEpoch, collTimestamp);
+    uint32_t origMajorVersion = 15;
+    auto const origVersion = ChunkVersion({collEpoch, collTimestamp}, {origMajorVersion, 4});
 
     ChunkType chunk0;
     chunk0.setName(OID::gen());
@@ -289,7 +285,7 @@ TEST_F(CommitChunkMigrate, CheckCorrectOpsCommandNoCtlTrimHistory) {
     // Verify the version returned matches expected value.
     BSONObj versions = resultBSON.getValue();
     auto mver = ChunkVersion::parse(versions["shardVersion"]);
-    ASSERT_EQ(ChunkVersion(0, 0, origVersion.epoch(), origVersion.getTimestamp()), mver);
+    ASSERT_EQ(ChunkVersion({origVersion.epoch(), origVersion.getTimestamp()}, {0, 0}), mver);
 
     // Verify the chunk ended up in the right shard.
     auto chunkDoc0 =
@@ -314,9 +310,8 @@ TEST_F(CommitChunkMigrate, RejectOutOfOrderHistory) {
 
     setupShards({shard0, shard1});
 
-    int origMajorVersion = 15;
-    auto const origVersion =
-        ChunkVersion(origMajorVersion, 4, OID::gen(), Timestamp(42) /* timestamp */);
+    uint32_t origMajorVersion = 15;
+    auto const origVersion = ChunkVersion({OID::gen(), Timestamp(42)}, {origMajorVersion, 4});
 
     ChunkType chunk0;
     chunk0.setName(OID::gen());
@@ -362,9 +357,8 @@ TEST_F(CommitChunkMigrate, RejectWrongCollectionEpoch0) {
 
     setupShards({shard0, shard1});
 
-    int origMajorVersion = 12;
-    auto const origVersion =
-        ChunkVersion(origMajorVersion, 7, OID::gen(), Timestamp(42) /* timestamp */);
+    uint32_t origMajorVersion = 12;
+    auto const origVersion = ChunkVersion({OID::gen(), Timestamp(42)}, {origMajorVersion, 7});
 
     ChunkType chunk0;
     chunk0.setName(OID::gen());
@@ -418,11 +412,9 @@ TEST_F(CommitChunkMigrate, RejectWrongCollectionEpoch1) {
 
     setupShards({shard0, shard1});
 
-    int origMajorVersion = 12;
-    auto const origVersion =
-        ChunkVersion(origMajorVersion, 7, OID::gen(), Timestamp(42) /* timestamp */);
-    auto const otherVersion =
-        ChunkVersion(origMajorVersion, 7, OID::gen(), Timestamp(42) /* timestamp */);
+    uint32_t origMajorVersion = 12;
+    auto const origVersion = ChunkVersion({OID::gen(), Timestamp(42)}, {origMajorVersion, 7});
+    auto const otherVersion = ChunkVersion({OID::gen(), Timestamp(42)}, {origMajorVersion, 7});
 
     ChunkType chunk0;
     chunk0.setName(OID::gen());
@@ -479,8 +471,8 @@ TEST_F(CommitChunkMigrate, CommitWithLastChunkOnShardShouldNotAffectOtherChunks)
 
     setupShards({shard0, shard1});
 
-    int origMajorVersion = 12;
-    auto const origVersion = ChunkVersion(origMajorVersion, 7, collEpoch, collTimestamp);
+    uint32_t origMajorVersion = 12;
+    auto const origVersion = ChunkVersion({collEpoch, collTimestamp}, {origMajorVersion, 7});
 
     ChunkType chunk0;
     chunk0.setName(OID::gen());
@@ -526,7 +518,7 @@ TEST_F(CommitChunkMigrate, CommitWithLastChunkOnShardShouldNotAffectOtherChunks)
     // Verify the versions returned match expected values.
     BSONObj versions = resultBSON.getValue();
     auto mver = ChunkVersion::parse(versions["shardVersion"]);
-    ASSERT_EQ(ChunkVersion(0, 0, origVersion.epoch(), origVersion.getTimestamp()), mver);
+    ASSERT_EQ(ChunkVersion({origVersion.epoch(), origVersion.getTimestamp()}, {0, 0}), mver);
 
     // Verify the chunks ended up in the right shards.
     auto chunkDoc0 =
@@ -560,7 +552,7 @@ TEST_F(CommitChunkMigrate, RejectMissingChunkVersion) {
 
     setupShards({shard0, shard1});
 
-    ChunkVersion origVersion(12, 7, OID::gen(), Timestamp(42) /* timestamp */);
+    ChunkVersion origVersion({OID::gen(), Timestamp(42)}, {12, 7});
 
     // Create migrate chunk with no chunk version set.
     ChunkType migratedChunk;
@@ -610,7 +602,7 @@ TEST_F(CommitChunkMigrate, RejectOlderChunkVersion) {
     setupShards({shard0, shard1});
 
     auto epoch = OID::gen();
-    ChunkVersion origVersion(12, 7, epoch, Timestamp(42) /* timestamp */);
+    ChunkVersion origVersion({epoch, Timestamp(42)}, {12, 7});
 
     ChunkType migratedChunk;
     migratedChunk.setName(OID::gen());
@@ -621,7 +613,7 @@ TEST_F(CommitChunkMigrate, RejectOlderChunkVersion) {
     migratedChunk.setMin(BSON("a" << 1));
     migratedChunk.setMax(BSON("a" << 10));
 
-    ChunkVersion currentChunkVersion(14, 7, epoch, Timestamp(42) /* timestamp */);
+    ChunkVersion currentChunkVersion({epoch, Timestamp(42)}, {14, 7});
 
     ChunkType currentChunk;
     currentChunk.setName(OID::gen());
@@ -662,7 +654,7 @@ TEST_F(CommitChunkMigrate, RejectMismatchedEpoch) {
 
     setupShards({shard0, shard1});
 
-    ChunkVersion origVersion(12, 7, OID::gen(), Timestamp(42) /* timestamp */);
+    ChunkVersion origVersion({OID::gen(), Timestamp(42)}, {12, 7});
 
     ChunkType migratedChunk;
     migratedChunk.setName(OID::gen());
@@ -673,7 +665,7 @@ TEST_F(CommitChunkMigrate, RejectMismatchedEpoch) {
     migratedChunk.setMin(BSON("a" << 1));
     migratedChunk.setMax(BSON("a" << 10));
 
-    ChunkVersion currentChunkVersion(12, 7, OID::gen(), Timestamp(42) /* timestamp */);
+    ChunkVersion currentChunkVersion({OID::gen(), Timestamp(42)}, {12, 7});
 
     ChunkType currentChunk;
     currentChunk.setName(OID::gen());
@@ -730,7 +722,7 @@ public:
     void setupCollectionWithNChunks(int numberOfChunks) {
         invariant(numberOfChunks > 0);
 
-        int currentMajorVersion = 1;
+        uint32_t currentMajorVersion = 1;
         int historyTimestampSecond = 100;
 
         std::vector<ChunkHistory> history;
@@ -745,7 +737,7 @@ public:
             const auto max = chunksMin.at(i + 1);      // Max key of the chunk being created
             const auto shardId = _shardIds.at(i % 2);  // Shard owning the chunk
             ChunkVersion version =
-                ChunkVersion(currentMajorVersion++, 0, _collEpoch, _collTimestamp);
+                ChunkVersion({_collEpoch, _collTimestamp}, {currentMajorVersion++, 0});
             history.insert(history.begin(),
                            {ChunkHistory(Timestamp(historyTimestampSecond++, 0), shardId)});
             ChunkType chunk = createChunk(_collUUID, min, max, version, shardId, history);
diff --git a/src/mongo/db/s/config/sharding_catalog_manager_remove_shard_test.cpp b/src/mongo/db/s/config/sharding_catalog_manager_remove_shard_test.cpp
index 32544cacc7b..b54338947b1 100644
--- a/src/mongo/db/s/config/sharding_catalog_manager_remove_shard_test.cpp
+++ b/src/mongo/db/s/config/sharding_catalog_manager_remove_shard_test.cpp
@@ -27,9 +27,6 @@
  *    it in the license file.
  */
 
-
-#include "mongo/platform/basic.h"
-
 #include <string>
 #include <vector>
 
@@ -58,7 +55,6 @@
 
 #define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kSharding
 
-
 namespace mongo {
 namespace {
 
@@ -227,15 +223,15 @@ TEST_F(RemoveShardTest, RemoveShardStillDrainingChunksRemaining) {
     const auto timestamp = Timestamp(1);
     ChunkType chunk1(uuid,
                      ChunkRange(BSON("_id" << 0), BSON("_id" << 20)),
-                     ChunkVersion(1, 1, epoch, timestamp),
+                     ChunkVersion({epoch, timestamp}, {1, 1}),
                      shard1.getName());
     ChunkType chunk2(uuid,
                      ChunkRange(BSON("_id" << 21), BSON("_id" << 50)),
-                     ChunkVersion(1, 2, epoch, timestamp),
+                     ChunkVersion({epoch, timestamp}, {1, 2}),
                      shard1.getName());
     ChunkType chunk3(uuid,
                      ChunkRange(BSON("_id" << 51), BSON("_id" << 1000)),
-                     ChunkVersion(1, 3, epoch, timestamp),
+                     ChunkVersion({epoch, timestamp}, {1, 3}),
                      shard1.getName());
 
     chunk3.setJumbo(true);
@@ -314,15 +310,15 @@ TEST_F(RemoveShardTest, RemoveShardCompletion) {
     Timestamp timestamp = Timestamp(1);
     ChunkType chunk1(uuid,
                      ChunkRange(BSON("_id" << 0), BSON("_id" << 20)),
-                     ChunkVersion(1, 1, epoch, timestamp),
+                     ChunkVersion({epoch, timestamp}, {1, 1}),
                      shard1.getName());
     ChunkType chunk2(uuid,
                      ChunkRange(BSON("_id" << 21), BSON("_id" << 50)),
-                     ChunkVersion(1, 2, epoch, timestamp),
+                     ChunkVersion({epoch, timestamp}, {1, 2}),
                      shard1.getName());
     ChunkType chunk3(uuid,
                      ChunkRange(BSON("_id" << 51), BSON("_id" << 1000)),
-                     ChunkVersion(1, 3, epoch, timestamp),
+                     ChunkVersion({epoch, timestamp}, {1, 3}),
                      shard1.getName());
 
     std::vector<ChunkType> chunks{chunk1, chunk2, chunk3};
diff --git a/src/mongo/db/s/migration_chunk_cloner_source_legacy_test.cpp b/src/mongo/db/s/migration_chunk_cloner_source_legacy_test.cpp
index 561bcbb713a..dc1eb4579e5 100644
--- a/src/mongo/db/s/migration_chunk_cloner_source_legacy_test.cpp
+++ b/src/mongo/db/s/migration_chunk_cloner_source_legacy_test.cpp
@@ -179,7 +179,7 @@ protected:
                 true,
                 {ChunkType{uuid,
                            ChunkRange{BSON(kShardKey << MINKEY), BSON(kShardKey << MAXKEY)},
-                           ChunkVersion(1, 0, epoch, timestamp),
+                           ChunkVersion({epoch, timestamp}, {1, 0}),
                            ShardId("dummyShardId")}});
 
             AutoGetDb autoDb(operationContext(), kNss.db(), MODE_IX);
diff --git a/src/mongo/db/s/migration_util_test.cpp b/src/mongo/db/s/migration_util_test.cpp
index 8e6f02043da..90a1e9016a1 100644
--- a/src/mongo/db/s/migration_util_test.cpp
+++ b/src/mongo/db/s/migration_util_test.cpp
@@ -27,8 +27,6 @@
  *    it in the license file.
  */
 
-#include "mongo/platform/basic.h"
-
 #include "mongo/client/remote_command_targeter_factory_mock.h"
 #include "mongo/client/remote_command_targeter_mock.h"
 #include "mongo/db/catalog_raii.h"
@@ -591,7 +589,7 @@ TEST_F(SubmitRangeDeletionTaskTest, SucceedsIfFilteringMetadataUUIDMatchesTaskUU
     _mockCatalogCacheLoader->setDatabaseRefreshReturnValue(kDefaultDatabaseType);
     _mockCatalogCacheLoader->setCollectionRefreshReturnValue(coll);
     _mockCatalogCacheLoader->setChunkRefreshReturnValue(
-        makeChangedChunks(ChunkVersion(1, 0, kEpoch, kDefaultTimestamp)));
+        makeChangedChunks(ChunkVersion({kEpoch, kDefaultTimestamp}, {1, 0})));
     _mockCatalogClient->setCollections({coll});
     forceShardFilteringMetadataRefresh(opCtx, kTestNss);
 
@@ -619,7 +617,7 @@ TEST_F(
     _mockCatalogCacheLoader->setDatabaseRefreshReturnValue(kDefaultDatabaseType);
     _mockCatalogCacheLoader->setCollectionRefreshReturnValue(coll);
     _mockCatalogCacheLoader->setChunkRefreshReturnValue(
-        makeChangedChunks(ChunkVersion(1, 0, kEpoch, kDefaultTimestamp)));
+        makeChangedChunks(ChunkVersion({kEpoch, kDefaultTimestamp}, {1, 0})));
     _mockCatalogClient->setCollections({coll});
 
     auto metadata = makeShardedMetadata(opCtx, collectionUUID);
@@ -654,7 +652,7 @@ TEST_F(SubmitRangeDeletionTaskTest,
     auto matchingColl = makeCollectionType(collectionUUID, kEpoch, kDefaultTimestamp);
     _mockCatalogCacheLoader->setCollectionRefreshReturnValue(matchingColl);
     _mockCatalogCacheLoader->setChunkRefreshReturnValue(
-        makeChangedChunks(ChunkVersion(10, 0, kEpoch, kDefaultTimestamp)));
+        makeChangedChunks(ChunkVersion({kEpoch, kDefaultTimestamp}, {10, 0})));
     _mockCatalogClient->setCollections({matchingColl});
 
     auto metadata = makeShardedMetadata(opCtx, collectionUUID);
@@ -684,7 +682,7 @@ TEST_F(SubmitRangeDeletionTaskTest,
     _mockCatalogCacheLoader->setDatabaseRefreshReturnValue(kDefaultDatabaseType);
     _mockCatalogCacheLoader->setCollectionRefreshReturnValue(otherColl);
     _mockCatalogCacheLoader->setChunkRefreshReturnValue(
-        makeChangedChunks(ChunkVersion(1, 0, otherEpoch, otherTimestamp)));
+        makeChangedChunks(ChunkVersion({otherEpoch, otherTimestamp}, {1, 0})));
     _mockCatalogClient->setCollections({otherColl});
 
     // The task should not have been submitted, and the task's entry should have been removed from
diff --git a/src/mongo/db/s/op_observer_sharding_test.cpp b/src/mongo/db/s/op_observer_sharding_test.cpp
index 1ef41426f26..2c4859ba782 100644
--- a/src/mongo/db/s/op_observer_sharding_test.cpp
+++ b/src/mongo/db/s/op_observer_sharding_test.cpp
@@ -27,8 +27,6 @@
  *    it in the license file.
  */
 
-#include "mongo/platform/basic.h"
-
 #include "mongo/db/catalog_raii.h"
 #include "mongo/db/op_observer_util.h"
 #include "mongo/db/s/collection_sharding_runtime.h"
@@ -59,8 +57,10 @@ protected:
         const UUID uuid = UUID::gen();
         const OID epoch = OID::gen();
         auto range = ChunkRange(BSON("key" << MINKEY), BSON("key" << MAXKEY));
-        auto chunk = ChunkType(
-            uuid, std::move(range), ChunkVersion(1, 0, epoch, Timestamp(1, 1)), ShardId("other"));
+        auto chunk = ChunkType(uuid,
+                               std::move(range),
+                               ChunkVersion({epoch, Timestamp(1, 1)}, {1, 0}),
+                               ShardId("other"));
         auto rt = RoutingTableHistory::makeNew(kTestNss,
                                                uuid,
                                                KeyPattern(keyPattern),
diff --git a/src/mongo/db/s/range_deletion_util_test.cpp b/src/mongo/db/s/range_deletion_util_test.cpp
index 6efd33ce9d6..567d50748df 100644
--- a/src/mongo/db/s/range_deletion_util_test.cpp
+++ b/src/mongo/db/s/range_deletion_util_test.cpp
@@ -27,8 +27,6 @@
  *    it in the license file.
  */
 
-#include "mongo/platform/basic.h"
-
 #include "mongo/db/catalog/create_collection.h"
 #include "mongo/db/db_raii.h"
 #include "mongo/db/dbdirectclient.h"
@@ -113,7 +111,7 @@ public:
             true,
             {ChunkType{uuid,
                        ChunkRange{BSON(kShardKey << MINKEY), BSON(kShardKey << MAXKEY)},
-                       ChunkVersion(1, 0, epoch, Timestamp(1, 1)),
+                       ChunkVersion({epoch, Timestamp(1, 1)}, {1, 0}),
                        ShardId("dummyShardId")}});
         ChunkManager cm(ShardId("dummyShardId"),
                         DatabaseVersion(UUID::gen(), Timestamp(1, 1)),
diff --git a/src/mongo/db/s/resharding/resharding_coordinator_service.cpp b/src/mongo/db/s/resharding/resharding_coordinator_service.cpp
index 4f905f80f51..26ba0393ccc 100644
--- a/src/mongo/db/s/resharding/resharding_coordinator_service.cpp
+++ b/src/mongo/db/s/resharding/resharding_coordinator_service.cpp
@@ -27,9 +27,6 @@
  *    it in the license file.
  */
 
-
-#include "mongo/platform/basic.h"
-
 #include "mongo/db/s/resharding/resharding_coordinator_service.h"
 
 #include "mongo/base/string_data.h"
@@ -79,7 +76,6 @@
 
 #define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kResharding
 
-
 namespace mongo {
 namespace {
 
@@ -857,7 +853,7 @@ ChunkVersion ReshardingCoordinatorExternalState::calculateChunkVersionForInitial
     OperationContext* opCtx) {
     const auto now = VectorClock::get(opCtx)->getTime();
     const auto timestamp = now.clusterTime().asTimestamp();
-    return ChunkVersion(1, 0, OID::gen(), timestamp);
+    return ChunkVersion({OID::gen(), timestamp}, {1, 0});
 }
 
 std::vector<DonorShardEntry> constructDonorShardEntries(const std::set<ShardId>& donorShardIds) {
diff --git a/src/mongo/db/s/resharding/resharding_coordinator_test.cpp b/src/mongo/db/s/resharding/resharding_coordinator_test.cpp
index 4a8a994f144..35ffa75b31a 100644
--- a/src/mongo/db/s/resharding/resharding_coordinator_test.cpp
+++ b/src/mongo/db/s/resharding/resharding_coordinator_test.cpp
@@ -27,10 +27,6 @@
  *    it in the license file.
  */
 
-#include "mongo/db/s/resharding/coordinator_document_gen.h"
-
-#include "mongo/platform/basic.h"
-
 #include <boost/optional.hpp>
 
 #include "mongo/client/remote_command_targeter_mock.h"
@@ -40,6 +36,7 @@
 #include "mongo/db/repl/storage_interface_mock.h"
 #include "mongo/db/s/config/config_server_test_fixture.h"
 #include "mongo/db/s/config/index_on_config.h"
+#include "mongo/db/s/resharding/coordinator_document_gen.h"
 #include "mongo/db/s/resharding/resharding_coordinator_service.h"
 #include "mongo/db/s/resharding/resharding_util.h"
 #include "mongo/db/s/transaction_coordinator_service.h"
@@ -52,7 +49,6 @@
 
 #define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kTest
 
-
 namespace mongo {
 namespace {
 
@@ -179,7 +175,7 @@ protected:
             _newShardKey.isShardKey(shardKey.toBSON()) ? _newChunkRanges : _oldChunkRanges;
 
         // Create two chunks, one on each shard with the given namespace and epoch
-        ChunkVersion version(1, 0, epoch, Timestamp(1, 2));
+        ChunkVersion version({epoch, Timestamp(1, 2)}, {1, 0});
         ChunkType chunk1(uuid, chunkRanges[0], version, ShardId("shard0000"));
         chunk1.setName(ids[0]);
         version.incMinor();
@@ -226,7 +222,7 @@ protected:
         client.insert(CollectionType::ConfigNS.ns(), originalNssCatalogEntry.toBSON());
 
         auto tempNssCatalogEntry = createTempReshardingCollectionType(
-            opCtx, coordinatorDoc, ChunkVersion(1, 1, OID::gen(), Timestamp(1, 2)), BSONObj());
+            opCtx, coordinatorDoc, ChunkVersion({OID::gen(), Timestamp(1, 2)}, {1, 1}), BSONObj());
         client.insert(CollectionType::ConfigNS.ns(), tempNssCatalogEntry.toBSON());
 
         return coordinatorDoc;
@@ -518,11 +514,11 @@ protected:
         // collection should have been removed.
         boost::optional<CollectionType> expectedTempCollType = boost::none;
         if (expectedCoordinatorDoc.getState() < CoordinatorStateEnum::kCommitting) {
-            expectedTempCollType =
-                createTempReshardingCollectionType(opCtx,
-                                                   expectedCoordinatorDoc,
-                                                   ChunkVersion(1, 1, OID::gen(), Timestamp(1, 2)),
-                                                   BSONObj());
+            expectedTempCollType = createTempReshardingCollectionType(
+                opCtx,
+                expectedCoordinatorDoc,
+                ChunkVersion({OID::gen(), Timestamp(1, 2)}, {1, 1}),
+                BSONObj());
 
             // It's necessary to add the userCanceled field because the call into
             // createTempReshardingCollectionType assumes that the collection entry is
diff --git a/src/mongo/db/s/resharding/resharding_destined_recipient_test.cpp b/src/mongo/db/s/resharding/resharding_destined_recipient_test.cpp
index d95f0fdc23e..632b387a817 100644
--- a/src/mongo/db/s/resharding/resharding_destined_recipient_test.cpp
+++ b/src/mongo/db/s/resharding/resharding_destined_recipient_test.cpp
@@ -27,9 +27,6 @@
  *    it in the license file.
  */
 
-
-#include "mongo/platform/basic.h"
-
 #include "mongo/db/catalog/create_collection.h"
 #include "mongo/db/catalog_raii.h"
 #include "mongo/db/dbdirectclient.h"
@@ -55,7 +52,6 @@
 
 #define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kTest
 
-
 namespace mongo {
 namespace {
 
@@ -164,11 +160,11 @@ protected:
                                         const std::string& shardKey) {
         auto range1 = ChunkRange(BSON(shardKey << MINKEY), BSON(shardKey << 5));
         ChunkType chunk1(
-            uuid, range1, ChunkVersion(1, 0, epoch, timestamp), kShardList[0].getName());
+            uuid, range1, ChunkVersion({epoch, timestamp}, {1, 0}), kShardList[0].getName());
 
         auto range2 = ChunkRange(BSON(shardKey << 5), BSON(shardKey << MAXKEY));
         ChunkType chunk2(
-            uuid, range2, ChunkVersion(1, 0, epoch, timestamp), kShardList[1].getName());
+            uuid, range2, ChunkVersion({epoch, timestamp}, {1, 0}), kShardList[1].getName());
 
         return {chunk1, chunk2};
     }
@@ -199,7 +195,7 @@ protected:
 
         ReshardingEnv env(CollectionCatalog::get(opCtx)->lookupUUIDByNSS(opCtx, kNss).value());
         env.destShard = kShardList[1].getName();
-        env.version = ChunkVersion(1, 0, OID::gen(), Timestamp(1, 1));
+        env.version = ChunkVersion({OID::gen(), Timestamp(1, 1)}, {1, 0});
         env.tempNss =
             NamespaceString(kNss.db(),
                             fmt::format("{}{}",
diff --git a/src/mongo/db/s/resharding/resharding_oplog_applier_test.cpp b/src/mongo/db/s/resharding/resharding_oplog_applier_test.cpp
index f3171d09254..d2313684ff9 100644
--- a/src/mongo/db/s/resharding/resharding_oplog_applier_test.cpp
+++ b/src/mongo/db/s/resharding/resharding_oplog_applier_test.cpp
@@ -27,9 +27,6 @@
  *    it in the license file.
  */
 
-
-#include "mongo/platform/basic.h"
-
 #include <fmt/format.h>
 
 #include "mongo/db/cancelable_operation_context.h"
@@ -64,7 +61,6 @@
 
 #define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kTest
 
-
 namespace mongo {
 namespace {
 
@@ -194,17 +190,17 @@ public:
                 kCrudUUID,
                 ChunkRange{BSON(kOriginalShardKey << MINKEY),
                            BSON(kOriginalShardKey << -std::numeric_limits<double>::infinity())},
-                ChunkVersion(1, 0, epoch, Timestamp(1, 1)),
+                ChunkVersion({epoch, Timestamp(1, 1)}, {1, 0}),
                 _sourceId.getShardId()},
             ChunkType{
                 kCrudUUID,
                 ChunkRange{BSON(kOriginalShardKey << -std::numeric_limits<double>::infinity()),
                            BSON(kOriginalShardKey << 0)},
-                ChunkVersion(1, 0, epoch, Timestamp(1, 1)),
+                ChunkVersion({epoch, Timestamp(1, 1)}, {1, 0}),
                 kOtherShardId},
             ChunkType{kCrudUUID,
                       ChunkRange{BSON(kOriginalShardKey << 0), BSON(kOriginalShardKey << MAXKEY)},
-                      ChunkVersion(1, 0, epoch, Timestamp(1, 1)),
+                      ChunkVersion({epoch, Timestamp(1, 1)}, {1, 0}),
                       _sourceId.getShardId()}};
 
         auto rt = RoutingTableHistory::makeNew(kCrudNs,
diff --git a/src/mongo/db/s/resharding/resharding_oplog_batch_applier_test.cpp b/src/mongo/db/s/resharding/resharding_oplog_batch_applier_test.cpp
index c88884ac624..ca596e65e16 100644
--- a/src/mongo/db/s/resharding/resharding_oplog_batch_applier_test.cpp
+++ b/src/mongo/db/s/resharding/resharding_oplog_batch_applier_test.cpp
@@ -27,9 +27,6 @@
  *    it in the license file.
  */
 
-
-#include "mongo/platform/basic.h"
-
 #include <boost/optional/optional_io.hpp>
 #include <memory>
 #include <vector>
@@ -66,7 +63,6 @@
 
 #define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kTest
 
-
 namespace mongo {
 namespace {
 
@@ -318,7 +314,7 @@ private:
         std::vector<ChunkType> chunks = {ChunkType{
             _sourceUUID,
             ChunkRange{BSON(_currentShardKey << MINKEY), BSON(_currentShardKey << MAXKEY)},
-            ChunkVersion(100, 0, epoch, Timestamp(1, 1)),
+            ChunkVersion({epoch, Timestamp(1, 1)}, {100, 0}),
             _myDonorId}};
 
         auto rt = RoutingTableHistory::makeNew(_sourceNss,
diff --git a/src/mongo/db/s/resharding/resharding_recipient_service_external_state_test.cpp b/src/mongo/db/s/resharding/resharding_recipient_service_external_state_test.cpp
index c4e193e6897..62776bba466 100644
--- a/src/mongo/db/s/resharding/resharding_recipient_service_external_state_test.cpp
+++ b/src/mongo/db/s/resharding/resharding_recipient_service_external_state_test.cpp
@@ -27,9 +27,6 @@
  *    it in the license file.
  */
 
-
-#include "mongo/platform/basic.h"
-
 #include "mongo/bson/unordered_fields_bsonobj_comparator.h"
 #include "mongo/db/catalog_raii.h"
 #include "mongo/db/dbdirectclient.h"
@@ -48,9 +45,6 @@
 #include "mongo/s/database_version.h"
 #include "mongo/s/stale_exception.h"
 
-#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kTest
-
-
 namespace mongo {
 namespace {
 
@@ -168,7 +162,7 @@ public:
             reshardingFields.setRecipientFields(recipientFields);
             coll.setReshardingFields(reshardingFields);
 
-            ChunkVersion version(1, 0, epoch, timestamp);
+            ChunkVersion version({epoch, timestamp}, {1, 0});
 
             ChunkType chunk(uuid,
                             {skey.getKeyPattern().globalMin(), skey.getKeyPattern().globalMax()},
@@ -193,7 +187,7 @@ public:
             CollectionType coll(
                 origNss, epoch, timestamp, Date_t::now(), uuid, skey.getKeyPattern());
 
-            ChunkVersion version(2, 0, epoch, timestamp);
+            ChunkVersion version({epoch, timestamp}, {2, 0});
 
             ChunkType chunk(uuid,
                             {skey.getKeyPattern().globalMin(), skey.getKeyPattern().globalMax()},
diff --git a/src/mongo/db/s/shard_server_catalog_cache_loader.cpp b/src/mongo/db/s/shard_server_catalog_cache_loader.cpp
index 283001c3b3e..93a685475d4 100644
--- a/src/mongo/db/s/shard_server_catalog_cache_loader.cpp
+++ b/src/mongo/db/s/shard_server_catalog_cache_loader.cpp
@@ -230,11 +230,9 @@ CollectionAndChangedChunks getPersistedMetadataSinceVersion(OperationContext* op
     // If the epochs are the same we can safely take the timestamp from the shard coll entry.
     ChunkVersion startingVersion = version.isSameCollection({shardCollectionEntry.getEpoch(),
                                                              shardCollectionEntry.getTimestamp()})
-        ? ChunkVersion(version.majorVersion(),
-                       version.minorVersion(),
-                       version.epoch(),
-                       shardCollectionEntry.getTimestamp())
-        : ChunkVersion(0, 0, shardCollectionEntry.getEpoch(), shardCollectionEntry.getTimestamp());
+        ? version
+        : ChunkVersion({shardCollectionEntry.getEpoch(), shardCollectionEntry.getTimestamp()},
+                       {0, 0});
 
     QueryAndSort diff = createShardChunkDiffQuery(startingVersion);
 
@@ -1277,16 +1275,7 @@ ShardServerCatalogCacheLoader::CollAndChunkTask::CollAndChunkTask(
     if (statusWithCollectionAndChangedChunks.isOK()) {
         collectionAndChangedChunks = std::move(statusWithCollectionAndChangedChunks.getValue());
         invariant(!collectionAndChangedChunks->changedChunks.empty());
-        const auto highestVersion = collectionAndChangedChunks->changedChunks.back().getVersion();
-        // Note that due to the way Phase 1 of the FCV upgrade writes timestamps to chunks
-        // (non-atomically), it is possible that chunks exist with timestamps, but the
-        // corresponding config.collections entry doesn't. In this case, the chunks timestamp
-        // should be ignored when computing the max query version and we should use the
-        // timestamp that comes from config.collections.
-        maxQueryVersion = ChunkVersion(highestVersion.majorVersion(),
-                                       highestVersion.minorVersion(),
-                                       highestVersion.epoch(),
-                                       collectionAndChangedChunks->timestamp);
+        maxQueryVersion = collectionAndChangedChunks->changedChunks.back().getVersion();
     } else {
         invariant(statusWithCollectionAndChangedChunks == ErrorCodes::NamespaceNotFound);
         dropped = true;
diff --git a/src/mongo/db/s/type_shard_collection.cpp b/src/mongo/db/s/type_shard_collection.cpp
index 30912e47a59..2628297e0d7 100644
--- a/src/mongo/db/s/type_shard_collection.cpp
+++ b/src/mongo/db/s/type_shard_collection.cpp
@@ -82,7 +82,7 @@ boost::optional<ChunkVersion> ShardCollectionType::getLastRefreshedCollectionVer
         return boost::none;
 
     Timestamp majorMinor = *getLastRefreshedCollectionMajorMinorVersion();
-    return ChunkVersion(majorMinor.getSecs(), majorMinor.getInc(), getEpoch(), getTimestamp());
+    return ChunkVersion({getEpoch(), getTimestamp()}, {majorMinor.getSecs(), majorMinor.getInc()});
 }
 
 }  // namespace mongo
diff --git a/src/mongo/s/catalog/sharding_catalog_client_test.cpp b/src/mongo/s/catalog/sharding_catalog_client_test.cpp
index effe9ca0a10..92f2ce78a8d 100644
--- a/src/mongo/s/catalog/sharding_catalog_client_test.cpp
+++ b/src/mongo/s/catalog/sharding_catalog_client_test.cpp
@@ -27,9 +27,6 @@
  *    it in the license file.
  */
 
-
-#include "mongo/platform/basic.h"
-
 #include <pcrecpp.h>
 
 #include "mongo/bson/json.h"
@@ -60,7 +57,6 @@
 
 #define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kSharding
 
-
 namespace mongo {
 namespace {
 
@@ -375,7 +371,7 @@ TEST_F(ShardingCatalogClientTest, GetChunksForNSWithSortAndLimit) {
     chunkA.setCollectionUUID(collUuid);
     chunkA.setMin(BSON("a" << 1));
     chunkA.setMax(BSON("a" << 100));
-    chunkA.setVersion({1, 2, collEpoch, collTimestamp});
+    chunkA.setVersion(ChunkVersion({collEpoch, collTimestamp}, {1, 2}));
     chunkA.setShard(ShardId("shard0000"));
 
     ChunkType chunkB;
@@ -383,10 +379,10 @@ TEST_F(ShardingCatalogClientTest, GetChunksForNSWithSortAndLimit) {
     chunkB.setCollectionUUID(collUuid);
     chunkB.setMin(BSON("a" << 100));
     chunkB.setMax(BSON("a" << 200));
-    chunkB.setVersion({3, 4, collEpoch, collTimestamp});
+    chunkB.setVersion(ChunkVersion({collEpoch, collTimestamp}, {3, 4}));
     chunkB.setShard(ShardId("shard0001"));
 
-    ChunkVersion queryChunkVersion({1, 2, collEpoch, collTimestamp});
+    ChunkVersion queryChunkVersion({collEpoch, collTimestamp}, {1, 2});
 
     const BSONObj chunksQuery(
         BSON(ChunkType::collectionUUID()
@@ -458,7 +454,7 @@ TEST_F(ShardingCatalogClientTest, GetChunksForUUIDNoSortNoLimit) {
     const auto collEpoch = OID::gen();
     const auto collTimestamp = Timestamp(1, 1);
 
-    ChunkVersion queryChunkVersion({1, 2, collEpoch, collTimestamp});
+    ChunkVersion queryChunkVersion({collEpoch, collTimestamp}, {1, 2});
 
     const BSONObj chunksQuery(
         BSON(ChunkType::collectionUUID()
@@ -507,7 +503,7 @@ TEST_F(ShardingCatalogClientTest, GetChunksForNSInvalidChunk) {
     configTargeter()->setFindHostReturnValue(HostAndPort("TestHost1"));
 
     const auto collUuid = UUID::gen();
-    ChunkVersion queryChunkVersion({1, 2, OID::gen(), Timestamp(1, 1)});
+    ChunkVersion queryChunkVersion({OID::gen(), Timestamp(1, 1)}, {1, 2});
 
     const BSONObj chunksQuery(
         BSON(ChunkType::collectionUUID()
@@ -533,14 +529,14 @@ TEST_F(ShardingCatalogClientTest, GetChunksForNSInvalidChunk) {
         chunkA.setCollectionUUID(collUuid);
         chunkA.setMin(BSON("a" << 1));
         chunkA.setMax(BSON("a" << 100));
-        chunkA.setVersion({1, 2, OID::gen(), Timestamp(1, 1)});
+        chunkA.setVersion(ChunkVersion({OID::gen(), Timestamp(1, 1)}, {1, 2}));
         chunkA.setShard(ShardId("shard0000"));
 
         ChunkType chunkB;
         chunkB.setCollectionUUID(collUuid);
         chunkB.setMin(BSON("a" << 100));
         chunkB.setMax(BSON("a" << 200));
-        chunkB.setVersion({3, 4, OID::gen(), Timestamp(1, 1)});
+        chunkB.setVersion(ChunkVersion({OID::gen(), Timestamp(1, 1)}, {3, 4}));
         // Missing shard id
 
         return vector<BSONObj>{chunkA.toConfigBSON(), chunkB.toConfigBSON()};
diff --git a/src/mongo/s/chunk_manager.cpp b/src/mongo/s/chunk_manager.cpp
index 92e54aa83bb..593b475ed46 100644
--- a/src/mongo/s/chunk_manager.cpp
+++ b/src/mongo/s/chunk_manager.cpp
@@ -130,6 +130,11 @@ void validateChunkIsNotOlderThan(const std::shared_ptr<ChunkInfo>& chunk,
 
 }  // namespace
 
+ChunkMap::ChunkMap(OID epoch, const Timestamp& timestamp, size_t initialCapacity)
+    : _collectionVersion({epoch, timestamp}, {0, 0}) {
+    _chunkMap.reserve(initialCapacity);
+}
+
 ShardVersionMap ChunkMap::constructShardVersionMap() const {
     ShardVersionMap shardVersions;
     ChunkVector::const_iterator current = _chunkMap.cbegin();
@@ -212,10 +217,7 @@ void ChunkMap::appendChunk(const std::shared_ptr<ChunkInfo>& chunk) {
     appendChunkTo(_chunkMap, chunk);
     const auto chunkVersion = chunk->getLastmod();
     if (_collectionVersion.isOlderThan(chunkVersion)) {
-        _collectionVersion = ChunkVersion(chunkVersion.majorVersion(),
-                                          chunkVersion.minorVersion(),
-                                          chunkVersion.epoch(),
-                                          _collTimestamp);
+        _collectionVersion = chunkVersion;
     }
 }
 
@@ -317,7 +319,7 @@ ChunkMap::_overlappingBounds(const BSONObj& min, const BSONObj& max, bool isMaxI
 }
 
 ShardVersionTargetingInfo::ShardVersionTargetingInfo(const OID& epoch, const Timestamp& timestamp)
-    : shardVersion(0, 0, epoch, timestamp) {}
+    : shardVersion({epoch, timestamp}, {0, 0}) {}
 
 RoutingTableHistory::RoutingTableHistory(
     NamespaceString nss,
@@ -748,7 +750,7 @@ ChunkVersion RoutingTableHistory::_getVersion(const ShardId& shardName,
         // Shards without explicitly tracked shard versions (meaning they have no chunks) always
         // have a version of (0, 0, epoch, timestamp)
         const auto collVersion = _chunkMap.getVersion();
-        return ChunkVersion(0, 0, collVersion.epoch(), collVersion.getTimestamp());
+        return ChunkVersion({collVersion.epoch(), collVersion.getTimestamp()}, {0, 0});
     }
 
     if (throwOnStaleShard && gEnableFinerGrainedCatalogCacheRefresh) {
diff --git a/src/mongo/s/chunk_manager.h b/src/mongo/s/chunk_manager.h
index 00c75957d37..7114caed9e7 100644
--- a/src/mongo/s/chunk_manager.h
+++ b/src/mongo/s/chunk_manager.h
@@ -75,10 +75,7 @@ class ChunkMap {
     using ChunkVector = std::vector<std::shared_ptr<ChunkInfo>>;
 
 public:
-    explicit ChunkMap(OID epoch, const Timestamp& timestamp, size_t initialCapacity = 0)
-        : _collectionVersion(0, 0, epoch, timestamp), _collTimestamp(timestamp) {
-        _chunkMap.reserve(initialCapacity);
-    }
+    ChunkMap(OID epoch, const Timestamp& timestamp, size_t initialCapacity = 0);
 
     size_t size() const {
         return _chunkMap.size();
@@ -130,14 +127,6 @@ private:
 
     // Max version across all chunks
     ChunkVersion _collectionVersion;
-
-    // Represents the timestamp present in config.collections for this ChunkMap.
-    //
-    // Note that due to the way Phase 1 of the FCV upgrade writes timestamps to chunks
-    // (non-atomically), it is possible that chunks exist with timestamps, but the corresponding
-    // config.collections entry doesn't. In this case, the chunks timestamp should be ignored when
-    // computing the collection version and we should use _collTimestamp instead.
-    Timestamp _collTimestamp;
 };
 
 /**
diff --git a/src/mongo/s/chunk_version.cpp b/src/mongo/s/chunk_version.cpp
index 12ed1ee72f7..ca260776a34 100644
--- a/src/mongo/s/chunk_version.cpp
+++ b/src/mongo/s/chunk_version.cpp
@@ -60,10 +60,8 @@ ChunkVersion ChunkVersion::parse(const BSONElement& element) {
     auto parsedVersion =
         ChunkVersion60Format::parse(IDLParserErrorContext("ChunkVersion"), element.Obj());
     auto version = parsedVersion.getVersion();
-    return ChunkVersion(version.getSecs(),
-                        version.getInc(),
-                        parsedVersion.getEpoch(),
-                        parsedVersion.getTimestamp());
+    return ChunkVersion({parsedVersion.getEpoch(), parsedVersion.getTimestamp()},
+                        {version.getSecs(), version.getInc()});
 }
 
 void ChunkVersion::serializeToBSON(StringData field, BSONObjBuilder* builder) const {
diff --git a/src/mongo/s/chunk_version.h b/src/mongo/s/chunk_version.h
index b25bae60691..68f33c6b018 100644
--- a/src/mongo/s/chunk_version.h
+++ b/src/mongo/s/chunk_version.h
@@ -53,12 +53,55 @@ public:
 
     std::string toString() const;
 
+    // TODO: Do not add any new usages of these methods. Use isSameCollection instead.
+
+    const OID& epoch() const {
+        return _epoch;
+    }
+
+    const Timestamp& getTimestamp() const {
+        return _timestamp;
+    }
+
 protected:
     OID _epoch;
     Timestamp _timestamp;
 };
 
 /**
+ * Reflects the placement information for a collection. An object of this class has no meaning on
+ * its own without the Generation component above, that's why most of its methods are protected and
+ * are exposed as semantic checks in ChunkVersion below.
+ */
+class CollectionPlacement {
+public:
+    CollectionPlacement(uint32_t major, uint32_t minor)
+        : _combined(static_cast<uint64_t>(minor) | (static_cast<uint64_t>(major) << 32)) {}
+
+    // TODO: Do not add any new usages of these methods. Use isSamePlacement instead.
+
+    uint32_t majorVersion() const {
+        return _combined >> 32;
+    }
+
+    uint32_t minorVersion() const {
+        return _combined & 0xFFFFFFFF;
+    }
+
+protected:
+    /**
+     * Returns whether two collection placements are compatible with each other (meaning that they
+     * refer to the same distribution of chunks across the cluster).
+     */
+    bool isSamePlacement(const CollectionPlacement& other) const {
+        return majorVersion() == other.majorVersion();
+    }
+
+    // The combined major/minor version, which exists as subordinate to the collection generation
+    uint64_t _combined;
+};
+
+/**
  * ChunkVersions consist of a major/minor version scoped to a version epoch
  *
  * Version configurations (format: major version, epoch):
@@ -68,7 +111,7 @@ protected:
  * 3. (n, 0), n > 0 - invalid configuration.
  * 4. (n, m), n > 0, m > 0 - normal sharded collection version.
  */
-class ChunkVersion : public CollectionGeneration {
+class ChunkVersion : public CollectionGeneration, public CollectionPlacement {
 public:
     /**
      * The name for the shard version information field, which shard-aware commands should include
@@ -76,11 +119,14 @@ public:
      */
     static constexpr StringData kShardVersionField = "shardVersion"_sd;
 
-    ChunkVersion(uint32_t major, uint32_t minor, const OID& epoch, const Timestamp& timestamp)
-        : CollectionGeneration(epoch, timestamp),
-          _combined(static_cast<uint64_t>(minor) | (static_cast<uint64_t>(major) << 32)) {}
+    ChunkVersion(CollectionGeneration geneneration, CollectionPlacement placement)
+        : CollectionGeneration(geneneration), CollectionPlacement(placement) {}
+
+    ChunkVersion() : ChunkVersion({OID(), Timestamp()}, {0, 0}) {}
 
-    ChunkVersion() : ChunkVersion(0, 0, OID(), Timestamp()) {}
+    // TODO: Do not add any new usages of this constructor. Use the one above instead.
+    ChunkVersion(uint32_t major, uint32_t minor, OID epoch, Timestamp timestamp)
+        : CollectionGeneration(epoch, timestamp), CollectionPlacement(major, minor) {}
 
     /**
      * Indicates that the collection is not sharded.
@@ -134,22 +180,6 @@ public:
         return _combined > 0;
     }
 
-    uint32_t majorVersion() const {
-        return _combined >> 32;
-    }
-
-    uint32_t minorVersion() const {
-        return _combined & 0xFFFFFFFF;
-    }
-
-    const OID& epoch() const {
-        return _epoch;
-    }
-
-    const Timestamp& getTimestamp() const {
-        return _timestamp;
-    }
-
     bool operator==(const ChunkVersion& otherVersion) const {
         return otherVersion.getTimestamp() == getTimestamp() && otherVersion._combined == _combined;
     }
@@ -160,7 +190,7 @@ public:
 
     // Can we write to this data and not have a problem?
     bool isWriteCompatibleWith(const ChunkVersion& other) const {
-        return isSameCollection(other) && majorVersion() == other.majorVersion();
+        return isSameCollection(other) && isSamePlacement(other);
     }
 
     // Unsharded timestamp cannot be compared with other timestamps
@@ -198,10 +228,6 @@ public:
     void serializeToBSON(StringData field, BSONObjBuilder* builder) const;
 
     std::string toString() const;
-
-private:
-    // The combined major/minor version, which exists as subordinate to the collection generation
-    uint64_t _combined;
 };
 
 inline std::ostream& operator<<(std::ostream& s, const ChunkVersion& v) {
diff --git a/src/mongo/s/query/cluster_exchange_test.cpp b/src/mongo/s/query/cluster_exchange_test.cpp
index 8b33c58e843..96815019657 100644
--- a/src/mongo/s/query/cluster_exchange_test.cpp
+++ b/src/mongo/s/query/cluster_exchange_test.cpp
@@ -27,8 +27,6 @@
  *    it in the license file.
  */
 
-#include "mongo/platform/basic.h"
-
 #include "mongo/client/remote_command_targeter_factory_mock.h"
 #include "mongo/client/remote_command_targeter_mock.h"
 #include "mongo/db/pipeline/document_source_group.h"
@@ -533,7 +531,7 @@ TEST_F(ClusterExchangeTest, CompoundShardKeyThreeShards) {
     const std::vector<std::string> xBoundaries = {"a", "g", "m", "r", "u"};
     auto chunks = [&]() {
         std::vector<ChunkType> chunks;
-        ChunkVersion version(1, 0, epoch, timestamp);
+        ChunkVersion version({epoch, timestamp}, {1, 0});
         chunks.emplace_back(uuid,
                             ChunkRange{BSON("x" << MINKEY << "y" << MINKEY),
                                        BSON("x" << xBoundaries[0] << "y" << MINKEY)},
diff --git a/src/mongo/s/request_types/balance_chunk_request_test.cpp b/src/mongo/s/request_types/balance_chunk_request_test.cpp
index 12ac80a5c09..a1475991bd2 100644
--- a/src/mongo/s/request_types/balance_chunk_request_test.cpp
+++ b/src/mongo/s/request_types/balance_chunk_request_test.cpp
@@ -41,7 +41,7 @@ using unittest::assertGet;
 
 TEST(BalanceChunkRequest, RoundTrip) {
     UUID uuid{UUID::gen()};
-    ChunkVersion version(30, 1, OID::gen(), Timestamp{2, 0});
+    ChunkVersion version({OID::gen(), Timestamp(2, 0)}, {30, 1});
     auto obj = BalanceChunkRequest::serializeToRebalanceCommandForConfig(
         NamespaceString("DB.Test"),
         ChunkRange(BSON("A" << 100), BSON("A" << 200)),
@@ -59,7 +59,7 @@ TEST(BalanceChunkRequest, RoundTrip) {
 
 TEST(BalanceChunkRequest, ParseFromConfigCommandNoSecondaryThrottle) {
     const auto uuid{UUID::gen()};
-    const ChunkVersion version(1, 0, OID::gen(), Timestamp(1, 1));
+    const ChunkVersion version({OID::gen(), Timestamp(1, 1)}, {1, 0});
     auto request = assertGet(BalanceChunkRequest::parseFromConfigCommand(
         BSON("_configsvrMoveChunk" << 1 << "ns"
                                    << "TestDB.TestColl"
@@ -83,7 +83,7 @@ TEST(BalanceChunkRequest, ParseFromConfigCommandNoSecondaryThrottle) {
 
 TEST(BalanceChunkRequest, ParseFromConfigCommandWithUUIDNoSecondaryThrottle) {
     const auto uuid = UUID::gen();
-    const ChunkVersion version(1, 0, OID::gen(), Timestamp(1, 1));
+    const ChunkVersion version({OID::gen(), Timestamp(1, 1)}, {1, 0});
     auto request = assertGet(BalanceChunkRequest::parseFromConfigCommand(
         BSON("_configsvrMoveChunk" << 1 << "ns"
                                    << "TestDB.TestColl"
@@ -107,7 +107,7 @@ TEST(BalanceChunkRequest, ParseFromConfigCommandWithUUIDNoSecondaryThrottle) {
 
 TEST(BalanceChunkRequest, ParseFromConfigCommandWithSecondaryThrottle) {
     const auto uuid{UUID::gen()};
-    const ChunkVersion version(1, 0, OID::gen(), Timestamp(1, 1));
+    const ChunkVersion version({OID::gen(), Timestamp(1, 1)}, {1, 0});
     auto request = assertGet(BalanceChunkRequest::parseFromConfigCommand(
         BSON("_configsvrMoveChunk"
              << 1 << "ns"
diff --git a/src/mongo/s/write_ops/batch_write_op_test.cpp b/src/mongo/s/write_ops/batch_write_op_test.cpp
index bfda09f0814..eb07226621f 100644
--- a/src/mongo/s/write_ops/batch_write_op_test.cpp
+++ b/src/mongo/s/write_ops/batch_write_op_test.cpp
@@ -27,8 +27,6 @@
  *    it in the license file.
  */
 
-#include "mongo/platform/basic.h"
-
 #include "mongo/s/concurrency/locker_mongos_client_observer.h"
 #include "mongo/s/mock_ns_targeter.h"
 #include "mongo/s/session_catalog_router.h"
@@ -289,8 +287,8 @@ TEST_F(BatchWriteOpTest, SingleStaleError) {
     response.addToErrDetails(
         write_ops::WriteError(0,
                               Status{StaleConfigInfo(nss,
-                                                     ChunkVersion(101, 200, epoch, timestamp),
-                                                     ChunkVersion(105, 200, epoch, timestamp),
+                                                     ChunkVersion({epoch, timestamp}, {101, 200}),
+                                                     ChunkVersion({epoch, timestamp}, {105, 200}),
                                                      ShardId("shard")),
                                      "mock stale error"}));