SERVER-61158 Convert a non-unique index to a unique index via the collMod command

2 files changed, 12 insertions, 2 deletions

diff --git a/jstests/core/collmod_convert_to_unique.js b/jstests/core/collmod_convert_to_unique.js
index 280f571c005..27bd11b0344 100644
--- a/jstests/core/collmod_convert_to_unique.js
+++ b/jstests/core/collmod_convert_to_unique.js
@@ -7,6 +7,10 @@
  *  assumes_no_implicit_collection_creation_after_drop,  # common tag in collMod tests.
  *  requires_fcv_52,
  *  requires_non_retryable_commands, # common tag in collMod tests.
+ *  # TODO(SERVER-61181): Fix validation errors under ephemeralForTest.
+ *  incompatible_with_eft,
+ *  # TODO(SERVER-61182): Fix WiredTigerKVEngine::alterIdentMetadata() under inMemory.
+ *  requires_persistence,
  * ]
  */
 
@@ -72,8 +76,8 @@ if (db.getMongo().isMongos()) {
 }
 
 // Look up index details in listIndexes output.
-assert.eq(countUnique({a: 1}), 0, 'index should not be unique yet: ' + tojson(coll.getIndexes()));
+assert.eq(countUnique({a: 1}), 1, 'index should be unique now: ' + tojson(coll.getIndexes()));
 
 // Test uniqueness constraint.
-assert.commandWorked(coll.insert({_id: 100, a: 100}));
+assert.commandFailedWithCode(coll.insert({_id: 100, a: 100}), ErrorCodes.DuplicateKey);
 })();
diff --git a/src/mongo/db/catalog/coll_mod_index.cpp b/src/mongo/db/catalog/coll_mod_index.cpp
index 9fbf29bab63..31207f38d3e 100644
--- a/src/mongo/db/catalog/coll_mod_index.cpp
+++ b/src/mongo/db/catalog/coll_mod_index.cpp
@@ -150,6 +150,7 @@ void _processCollModIndexRequestUnique(OperationContext* opCtx,
         return;
     }
     *newUnique = indexUnique;
+    autoColl->getWritableCollection()->updateUniqueSetting(opCtx, idx->indexName());
 }
 
 }  // namespace
@@ -206,6 +207,11 @@ void processCollModIndexRequest(OperationContext* opCtx,
     // This matches the default for IndexCatalog::refreshEntry().
     auto flags = CreateIndexEntryFlags::kIsReady;
 
+    // Update data format version in storage engine metadata for index.
+    if (indexUnique) {
+        flags = CreateIndexEntryFlags::kIsReady | CreateIndexEntryFlags::kUpdateMetadata;
+    }
+
     // Notify the index catalog that the definition of this index changed. This will invalidate the
     // local idx pointer. On rollback of this WUOW, the local var idx pointer will be valid again.
     autoColl->getWritableCollection()->getIndexCatalog()->refreshEntry(