From 9ba1b9d5cc02a43ea1b29a24f79c732c2fedfd20 Mon Sep 17 00:00:00 2001
From: Xinli Shang <shangx@uber.com>
Date: Sun, 21 Dec 2025 16:03:12 -0800
Subject: [PATCH 1/4] fix: prevent double-commit in Transaction

Prevents Transaction::Commit() from being called multiple times by:
- Adding committed_ flag to track transaction state
- Checking flag at start of Commit() and returning error if already committed
- Setting flag after successful commit (both empty and non-empty updates)
- Updating table_ reference after successful catalog update

This ensures transactions can only be committed once, preventing
unintended side effects and maintaining transaction semantics.
---
 src/iceberg/transaction.cc | 13 ++++++++++++-
 src/iceberg/transaction.h  |  2 ++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/iceberg/transaction.cc b/src/iceberg/transaction.cc
index ca39ec043..666d8fdd5 100644
--- a/src/iceberg/transaction.cc
+++ b/src/iceberg/transaction.cc
@@ -75,6 +75,9 @@ Status Transaction::Apply(std::vector<std::unique_ptr<TableUpdate>> updates) {
 }
 
 Result<std::shared_ptr<Table>> Transaction::Commit() {
+  if (committed_) {
+    return InvalidArgument("Transaction already committed");
+  }
   if (!last_update_committed_) {
     return InvalidArgument(
         "Cannot commit transaction when previous update is not committed");
@@ -82,6 +85,7 @@ Result<std::shared_ptr<Table>> Transaction::Commit() {
 
   const auto& updates = metadata_builder_->changes();
   if (updates.empty()) {
+    committed_ = true;
     return table_;
   }
 
@@ -98,7 +102,14 @@ Result<std::shared_ptr<Table>> Transaction::Commit() {
   }
 
   // XXX: we should handle commit failure and retry here.
-  return table_->catalog()->UpdateTable(table_->name(), requirements, updates);
+  ICEBERG_ASSIGN_OR_RAISE(auto updated_table, table_->catalog()->UpdateTable(
+                                                  table_->name(), requirements, updates));
+
+  // Mark as committed and update table reference
+  committed_ = true;
+  table_ = updated_table;
+
+  return updated_table;
 }
 
 Result<std::shared_ptr<UpdateProperties>> Transaction::NewUpdateProperties() {
diff --git a/src/iceberg/transaction.h b/src/iceberg/transaction.h
index 36328026b..73c346833 100644
--- a/src/iceberg/transaction.h
+++ b/src/iceberg/transaction.h
@@ -80,6 +80,8 @@ class ICEBERG_EXPORT Transaction : public std::enable_shared_from_this<Transacti
   const bool auto_commit_;
   // To make the state simple, we require updates are added and committed in order.
   bool last_update_committed_ = true;
+  // Tracks if transaction has been committed to prevent double-commit
+  bool committed_ = false;
   // Keep track of all created pending updates. Use weak_ptr to avoid circular references.
   // This is useful to retry failed updates.
   std::vector<std::weak_ptr<PendingUpdate>> pending_updates_;

From ead3c912118927024d8afd8c1155509185706fd2 Mon Sep 17 00:00:00 2001
From: Xinli Shang <xinlishang@gmail.com>
Date: Mon, 22 Dec 2025 06:47:02 -0800
Subject: [PATCH 2/4] Update src/iceberg/transaction.cc

Co-authored-by: Gang Wu <ustcwg@gmail.com>
---
 src/iceberg/transaction.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/iceberg/transaction.cc b/src/iceberg/transaction.cc
index 666d8fdd5..50064ea7d 100644
--- a/src/iceberg/transaction.cc
+++ b/src/iceberg/transaction.cc
@@ -107,7 +107,7 @@ Result<std::shared_ptr<Table>> Transaction::Commit() {
 
   // Mark as committed and update table reference
   committed_ = true;
-  table_ = updated_table;
+  table_ = std::move(updated_table);
 
   return updated_table;
 }

From 4bdeb7367447e0ca6cd24256f183fba45a1c59dd Mon Sep 17 00:00:00 2001
From: Xinli Shang <xinlishang@gmail.com>
Date: Mon, 22 Dec 2025 06:47:12 -0800
Subject: [PATCH 3/4] Update src/iceberg/transaction.cc

Co-authored-by: Gang Wu <ustcwg@gmail.com>
---
 src/iceberg/transaction.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/iceberg/transaction.cc b/src/iceberg/transaction.cc
index 50064ea7d..882a5895f 100644
--- a/src/iceberg/transaction.cc
+++ b/src/iceberg/transaction.cc
@@ -109,7 +109,7 @@ Result<std::shared_ptr<Table>> Transaction::Commit() {
   committed_ = true;
   table_ = std::move(updated_table);
 
-  return updated_table;
+  return table_;
 }
 
 Result<std::shared_ptr<UpdateProperties>> Transaction::NewUpdateProperties() {

From 9327954b4facfe75fe9a308a8823873c33dd0702 Mon Sep 17 00:00:00 2001
From: Xinli Shang <xinlishang@gmail.com>
Date: Mon, 22 Dec 2025 06:47:33 -0800
Subject: [PATCH 4/4] Update src/iceberg/transaction.cc

Co-authored-by: Gang Wu <ustcwg@gmail.com>
---
 src/iceberg/transaction.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/iceberg/transaction.cc b/src/iceberg/transaction.cc
index 882a5895f..c8cf42d36 100644
--- a/src/iceberg/transaction.cc
+++ b/src/iceberg/transaction.cc
@@ -76,7 +76,7 @@ Status Transaction::Apply(std::vector<std::unique_ptr<TableUpdate>> updates) {
 
 Result<std::shared_ptr<Table>> Transaction::Commit() {
   if (committed_) {
-    return InvalidArgument("Transaction already committed");
+    return Invalid("Transaction already committed");
   }
   if (!last_update_committed_) {
     return InvalidArgument(