fix: serialization failure on commit already closes the transaction

Author: lsunsi

src/transaction_manager.rs

@@ -328,12 +328,15 @@ where
         }
     }
 
-    /// If the transaction fails to commit due to a `SerializationFailure` or a
-    /// `ReadOnlyTransaction` a rollback will be attempted. If the rollback succeeds,
-    /// the original error will be returned, otherwise the error generated by the rollback
-    /// will be returned. In the second case the connection will be considered broken
-    /// as it contains a uncommitted unabortable open transaction.
+    /// If the transaction fails to commit due to a `ReadOnlyTransaction` a rollback will be
+    /// attempted. If the rollback succeeds, the original error will be returned, otherwise
+    /// the error generated by the rollback will be returned. In the second case the connection
+    /// will be considered broken as it contains a uncommitted unabortable open transaction.
+    /// If the transaction fails to commit due to a `SerializationFailure` no rollback will
+    /// be performed, because it already closes the transaction.
     async fn commit_transaction(conn: &mut Conn) -> QueryResult<()> {
+        use diesel::result::DatabaseErrorKind::SerializationFailure;
+
         let transaction_state = Self::get_transaction_state(conn)?;
         let transaction_depth = transaction_state.transaction_depth();
         let (commit_sql, committing_top_level) = match transaction_depth {
@@ -358,7 +361,7 @@ where
         let is_broken = conn.transaction_state().is_broken.clone();
 
         match Self::critical_transaction_block(&is_broken, conn.batch_execute(&commit_sql)).await {
-            Ok(()) => {
+            a @ (Ok(()) | Err(Error::DatabaseError(SerializationFailure, _))) => {
                 match Self::get_transaction_state(conn)?
                     .change_transaction_depth(TransactionDepthChange::DecreaseDepth)
                 {
@@ -369,7 +372,7 @@ where
                     }
                     Err(e) => return Err(e),
                 }
-                Ok(())
+                a
             }
             Err(commit_error) => {
                 if let TransactionManagerStatus::Valid(ValidTransactionManagerStatus {