1 files changed, 40 insertions, 18 deletions

diff --git a/src/mongo/db/catalog/coll_mod.cpp b/src/mongo/db/catalog/coll_mod.cpp
index 3bb76fee38b..2c9f03053d0 100644
--- a/src/mongo/db/catalog/coll_mod.cpp
+++ b/src/mongo/db/catalog/coll_mod.cpp
@@ -118,6 +118,7 @@ struct ParsedCollModRequest {
     bool dryRun = false;
     boost::optional<long long> cappedSize;
     boost::optional<long long> cappedMax;
+    boost::optional<bool> timeseriesBucketsMayHaveMixedSchemaData;
 };
 
 Status getNotSupportedOnViewError(StringData fieldName) {
@@ -400,6 +401,11 @@ StatusWith<std::pair<ParsedCollModRequest, BSONObj>> parseCollModRequest(Operati
         }
 
         if (cmdIndex.getPrepareUnique()) {
+            // Check if prepareUnique is being set on a time-series collection.
+            if (isTimeseries) {
+                return {ErrorCodes::InvalidOptions,
+                        "cannot set 'prepareUnique' for indexes of a time-series collection."};
+            }
             parsed.numModifications++;
             // Attempting to modify with the same value should be treated as a no-op.
             if (cmrIndex->idx->prepareUnique() == *cmdIndex.getPrepareUnique() ||
@@ -605,6 +611,17 @@ StatusWith<std::pair<ParsedCollModRequest, BSONObj>> parseCollModRequest(Operati
         timeseries->serialize(&subObjBuilder);
     }
 
+    if (auto mixedSchema = cmr.getTimeseriesBucketsMayHaveMixedSchemaData()) {
+        if (!isTimeseries) {
+            return getOnlySupportedOnTimeseriesError(
+                CollMod::kTimeseriesBucketsMayHaveMixedSchemaDataFieldName);
+        }
+
+        parsed.timeseriesBucketsMayHaveMixedSchemaData = mixedSchema;
+        oplogEntryBuilder.append(CollMod::kTimeseriesBucketsMayHaveMixedSchemaDataFieldName,
+                                 *mixedSchema);
+    }
+
     if (auto& dryRun = cmr.getDryRun()) {
         parsed.dryRun = *dryRun;
         // The dry run option should never be included in a collMod oplog entry.
@@ -930,6 +947,11 @@ Status _collModInternal(OperationContext* opCtx,
                                             *cmd.getExpireAfterSeconds());
         }
 
+        if (auto mixedSchema = cmrNew.timeseriesBucketsMayHaveMixedSchemaData) {
+            coll.getWritableCollection(opCtx)->setTimeseriesBucketsMayHaveMixedSchemaData(
+                opCtx, mixedSchema);
+        }
+
         // Handle index modifications.
         processCollModIndexRequest(
             opCtx, &coll, cmrNew.indexRequest, &indexCollModInfo, result, mode);
@@ -985,24 +1007,24 @@ Status _collModInternal(OperationContext* opCtx,
         // (Generic FCV reference): TODO SERVER-60912: When kLastLTS is 6.0, remove this FCV-gated
         // upgrade/downgrade code.
         const auto currentVersion = serverGlobalParams.featureCompatibility.getVersion();
-        if (coll->getTimeseriesOptions() && !coll->getTimeseriesBucketsMayHaveMixedSchemaData() &&
-            (currentVersion == multiversion::GenericFCV::kUpgradingFromLastLTSToLatest ||
-             currentVersion == multiversion::GenericFCV::kLatest)) {
-            // (Generic FCV reference): While upgrading the FCV from kLastLTS to kLatest, collMod is
-            // called as part of the upgrade process to add the
-            // 'timeseriesBucketsMayHaveMixedSchemaData=true' catalog entry flag for time-series
-            // collections that are missing the flag. This indicates that the time-series collection
-            // existed in earlier server versions and may have mixed-schema data.
-            coll.getWritableCollection(opCtx)->setTimeseriesBucketsMayHaveMixedSchemaData(opCtx,
-                                                                                          true);
-        } else if (coll->getTimeseriesBucketsMayHaveMixedSchemaData() &&
-                   (currentVersion == multiversion::GenericFCV::kDowngradingFromLatestToLastLTS ||
-                    currentVersion == multiversion::GenericFCV::kLastLTS)) {
-            // (Generic FCV reference): While downgrading the FCV to kLastLTS, collMod is called as
-            // part of the downgrade process to remove the 'timeseriesBucketsMayHaveMixedSchemaData'
-            // catalog entry flag for time-series collections that have the flag.
-            coll.getWritableCollection(opCtx)->setTimeseriesBucketsMayHaveMixedSchemaData(
-                opCtx, boost::none);
+        if (coll->getTimeseriesOptions()) {
+            if (currentVersion == multiversion::GenericFCV::kUpgradingFromLastLTSToLatest) {
+                // (Generic FCV reference): While upgrading the FCV from kLastLTS to kLatest,
+                // collMod is called as part of the upgrade process to add the
+                // 'timeseriesBucketsMayHaveMixedSchemaData=true' catalog entry flag for time-series
+                // collections that are missing the flag. This indicates that the time-series
+                // collection existed in earlier server versions and may have mixed-schema data.
+                coll.getWritableCollection(opCtx)->setTimeseriesBucketsMayHaveMixedSchemaData(opCtx,
+                                                                                              true);
+            } else if (currentVersion ==
+                       multiversion::GenericFCV::kDowngradingFromLatestToLastLTS) {
+                // (Generic FCV reference): While downgrading the FCV to kLastLTS, collMod is called
+                // as part of the downgrade process to remove the
+                // 'timeseriesBucketsMayHaveMixedSchemaData' catalog entry flag for time-series
+                // collections that have the flag.
+                coll.getWritableCollection(opCtx)->setTimeseriesBucketsMayHaveMixedSchemaData(
+                    opCtx, boost::none);
+            }
         }
 
         // Only observe non-view collMods, as view operations are observed as operations on the