SERVER-36005 Prevent unsafe IndexCatalogEntryImpl::_catalogIsReady call

1 files changed, 10 insertions, 4 deletions

diff --git a/src/mongo/db/catalog/index_catalog_entry_impl.cpp b/src/mongo/db/catalog/index_catalog_entry_impl.cpp
index f44e5a0f31e..09859e35b4c 100644
--- a/src/mongo/db/catalog/index_catalog_entry_impl.cpp
+++ b/src/mongo/db/catalog/index_catalog_entry_impl.cpp
@@ -167,10 +167,12 @@ bool IndexCatalogEntryImpl::isReady(OperationContext* opCtx) const {
     // minimumSnapshotVersion on a collection.  This means we are unprotected from reading
     // out-of-sync index catalog entries.  To fix this, we uassert if we detect that the
     // in-memory catalog is out-of-sync with the on-disk catalog.
-    if (session && session->inMultiDocumentTransaction() && _catalogIsReady(opCtx) != _isReady) {
-        uasserted(ErrorCodes::SnapshotUnavailable,
-                  str::stream() << "Unable to read from a snapshot due to pending collection"
-                                   " catalog changes; please retry the operation.");
+    if (session && session->inMultiDocumentTransaction()) {
+        if (!_catalogIsPresent(opCtx) || _catalogIsReady(opCtx) != _isReady) {
+            uasserted(ErrorCodes::SnapshotUnavailable,
+                      str::stream() << "Unable to read from a snapshot due to pending collection"
+                                       " catalog changes; please retry the operation.");
+        }
     }
 
     DEV invariant(_isReady == _catalogIsReady(opCtx));
@@ -360,6 +362,10 @@ RecordId IndexCatalogEntryImpl::_catalogHead(OperationContext* opCtx) const {
     return _collection->getIndexHead(opCtx, _descriptor->indexName());
 }
 
+bool IndexCatalogEntryImpl::_catalogIsPresent(OperationContext* opCtx) const {
+    return _collection->isIndexPresent(opCtx, _descriptor->indexName());
+}
+
 bool IndexCatalogEntryImpl::_catalogIsMultikey(OperationContext* opCtx,
                                                MultikeyPaths* multikeyPaths) const {
     return _collection->isIndexMultikey(opCtx, _descriptor->indexName(), multikeyPaths);