SERVER-79183 Change invariant on FCV not being initialized to assertion errorr7.0.0-rc9

3 files changed, 59 insertions, 3 deletions

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 28492ece9cc..875fbc30b1a 100644
--- a/src/mongo/db/s/shard_server_catalog_cache_loader.cpp
+++ b/src/mongo/db/s/shard_server_catalog_cache_loader.cpp
@@ -354,9 +354,19 @@ void forcePrimaryDatabaseRefreshAndWaitForReplication(OperationContext* opCtx, S
 
 // TODO: SERVER-74105 remove
 bool shouldSkipStoringLocally() {
-    // Note: cannot use isExclusivelyConfigSvrRole as it ignores fcv.
-    return serverGlobalParams.clusterRole.has(ClusterRole::ConfigServer) &&
-        !gFeatureFlagCatalogShard.isEnabled(serverGlobalParams.featureCompatibility);
+    // Note: cannot use isExclusivelyConfigSvrRole as it ignores the feature flag.
+    if (!serverGlobalParams.clusterRole.has(ClusterRole::ConfigServer)) {
+        return false;
+    }
+
+    const auto fcv = serverGlobalParams.featureCompatibility.getVersionMustVerifyInitialized();
+
+    // Note: it is possible for fcv to become uninitialized temporarily during initial sync.
+    uassert(7918300,
+            "feature compatibility version is not initialized",
+            fcv != multiversion::FeatureCompatibilityVersion::kUnsetDefaultLastLTSBehavior);
+
+    return !gFeatureFlagCatalogShard.isEnabledOnVersion(fcv);
 }
 
 }  // namespace
diff --git a/src/mongo/db/s/shard_server_catalog_cache_loader_test.cpp b/src/mongo/db/s/shard_server_catalog_cache_loader_test.cpp
index a4cc4fce1b8..dfa3ff36015 100644
--- a/src/mongo/db/s/shard_server_catalog_cache_loader_test.cpp
+++ b/src/mongo/db/s/shard_server_catalog_cache_loader_test.cpp
@@ -645,5 +645,44 @@ TEST_F(ShardServerCatalogCacheLoaderTest, setFCVForGetDatabase) {
     ASSERT_FALSE(cachedDoc.isEmpty());
 }
 
+TEST_F(ShardServerCatalogCacheLoaderTest, getChunksWithUninitializedFCV) {
+    const auto kOriginalRole = serverGlobalParams.clusterRole;
+    const auto kOriginalFCV = serverGlobalParams.featureCompatibility.getVersion();
+
+    ON_BLOCK_EXIT([&] {
+        serverGlobalParams.clusterRole = kOriginalRole;
+        serverGlobalParams.mutableFeatureCompatibility.setVersion(kOriginalFCV);
+    });
+
+    serverGlobalParams.clusterRole = ClusterRole::ConfigServer;
+    serverGlobalParams.mutableFeatureCompatibility.reset();
+
+    const ChunkVersion collectionPlacementVersion({OID::gen(), Timestamp(1, 1)}, {1, 2});
+    const auto collectionType = makeCollectionType(collectionPlacementVersion);
+
+    auto future = _shardLoader->getChunksSince(kNss, ChunkVersion::UNSHARDED());
+    ASSERT_THROWS_CODE(future.get(), DBException, 7918300);
+}
+
+TEST_F(ShardServerCatalogCacheLoaderTest, getChunksWithUninitializedFCVWhileSecondary) {
+    const auto kOriginalRole = serverGlobalParams.clusterRole;
+    const auto kOriginalFCV = serverGlobalParams.featureCompatibility.getVersion();
+
+    ON_BLOCK_EXIT([&] {
+        serverGlobalParams.clusterRole = kOriginalRole;
+        serverGlobalParams.mutableFeatureCompatibility.setVersion(kOriginalFCV);
+    });
+
+    serverGlobalParams.clusterRole = ClusterRole::ConfigServer;
+    serverGlobalParams.mutableFeatureCompatibility.reset();
+
+    const ChunkVersion collectionPlacementVersion({OID::gen(), Timestamp(1, 1)}, {1, 2});
+    const auto collectionType = makeCollectionType(collectionPlacementVersion);
+
+    _shardLoader->onStepDown();
+    auto future = _shardLoader->getChunksSince(kNss, ChunkVersion::UNSHARDED());
+    ASSERT_THROWS_CODE(future.get(), DBException, 7918300);
+}
+
 }  // namespace
 }  // namespace mongo
diff --git a/src/mongo/db/server_options.h b/src/mongo/db/server_options.h
index 36ce77d82e7..ac3f0dd385e 100644
--- a/src/mongo/db/server_options.h
+++ b/src/mongo/db/server_options.h
@@ -148,6 +148,13 @@ struct ServerGlobalParams {
             return _version.load();
         }
 
+        /**
+         * Returns the current version but caller is responsible for verifying if it's initialized.
+         */
+        FCV getVersionMustVerifyInitialized() const {
+            return _version.load();
+        }
+
         bool isLessThanOrEqualTo(FCV version, FCV* versionReturn = nullptr) const {
             auto currentVersion = getVersion();
             if (versionReturn != nullptr) {