SERVER-67946 added downgrading->upgrading path sharding tests

2 files changed, 16 insertions, 2 deletions

diff --git a/src/mongo/db/commands/feature_compatibility_version.cpp b/src/mongo/db/commands/feature_compatibility_version.cpp
index 674be1c4ff1..8ad7cae43f6 100644
--- a/src/mongo/db/commands/feature_compatibility_version.cpp
+++ b/src/mongo/db/commands/feature_compatibility_version.cpp
@@ -329,10 +329,10 @@ void FeatureCompatibilityVersion::updateFeatureCompatibilityVersionDocument(
 
     // Only transition to fully upgraded or downgraded states when we
     // have completed all required upgrade/downgrade behavior.
+    // If kDowngradingFromLatestToLastLTS->kLatest, we want to get the transitional version
+    // i.e. kUpgradingFromLastLTSToLatest
     auto transitioningVersion = setTargetVersion &&
             serverGlobalParams.featureCompatibility.isUpgradingOrDowngrading(fromVersion) &&
-            // if kDowngradingFromLatestToLastLTS->kLatest, we want to get the transitional version
-            // i.e. kUpgradingFromLastLTSToLatest
             !(fromVersion == GenericFCV::kDowngradingFromLatestToLastLTS &&
               newVersion == GenericFCV::kLatest)
         ? fromVersion
diff --git a/src/mongo/db/commands/set_feature_compatibility_version_command.cpp b/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
index 1b1e280ecd2..6ce53c6258b 100644
--- a/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
+++ b/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
@@ -103,11 +103,14 @@ namespace {
 
 using GenericFCV = multiversion::GenericFCV;
 
+MONGO_FAIL_POINT_DEFINE(failBeforeTransitioning);
 MONGO_FAIL_POINT_DEFINE(failUpgrading);
 MONGO_FAIL_POINT_DEFINE(hangWhileUpgrading);
+MONGO_FAIL_POINT_DEFINE(failBeforeSendingShardsToDowngrading);
 MONGO_FAIL_POINT_DEFINE(failDowngrading);
 MONGO_FAIL_POINT_DEFINE(hangWhileDowngrading);
 MONGO_FAIL_POINT_DEFINE(hangBeforeUpdatingFcvDoc);
+MONGO_FAIL_POINT_DEFINE(failBeforeUpdatingFcvDoc);
 
 /**
  * Ensures that only one instance of setFeatureCompatibilityVersion can run at a given time.
@@ -332,6 +335,10 @@ public:
                 const auto fcvChangeRegion(
                     FeatureCompatibilityVersion::enterFCVChangeRegion(opCtx));
 
+                uassert(ErrorCodes::Error(6744303),
+                        "Failing upgrade due to 'failBeforeTransitioning' failpoint set",
+                        !failBeforeTransitioning.shouldFail());
+
                 FeatureCompatibilityVersion::updateFeatureCompatibilityVersionDocument(
                     opCtx,
                     actualVersion,
@@ -392,6 +399,10 @@ public:
             // downgraded requestedVersion.
             const auto fcvChangeRegion(FeatureCompatibilityVersion::enterFCVChangeRegion(opCtx));
 
+            uassert(ErrorCodes::Error(6794601),
+                    "Failing downgrade due to 'failBeforeUpdatingFcvDoc' failpoint set",
+                    !failBeforeUpdatingFcvDoc.shouldFail());
+
             hangBeforeUpdatingFcvDoc.pauseWhileSet();
 
             FeatureCompatibilityVersion::updateFeatureCompatibilityVersionDocument(
@@ -731,6 +742,9 @@ private:
         boost::optional<SharedSemiFuture<void>> chunkResizeAsyncTask;
 
         if (serverGlobalParams.clusterRole == ClusterRole::ConfigServer) {
+            uassert(ErrorCodes::Error(6794600),
+                    "Failing downgrade due to 'failBeforeSendingShardsToDowngrading' failpoint set",
+                    !failBeforeSendingShardsToDowngrading.shouldFail());
             // Tell the shards to enter phase-1 of setFCV
             _sendSetFCVRequestToShards(opCtx, request, changeTimestamp, SetFCVPhaseEnum::kStart);
         }