From 4e24b4c36e9c364b41524c7e51cc284bed5cdb8a Mon Sep 17 00:00:00 2001
From: brad-defined <77982333+brad-defined@users.noreply.github.com>
Date: Mon, 21 Apr 2025 06:42:34 -0400
Subject: [PATCH] Transaction Commit/Rollback returns conn's cached error, if
 present (#1691)

If a transaction connection has a cached error, return it
instead of ErrInvalidConn during Commit/Rollback operations.
Fix #1690
---
 AUTHORS        |  2 ++
 transaction.go | 18 ++++++++++++++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/AUTHORS b/AUTHORS
index a261819f2..ec346e203 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -25,6 +25,7 @@ Asta Xie <xiemengjun at gmail.com>
 B Lamarche <blam413 at gmail.com>
 Bes Dollma <bdollma@thousandeyes.com>
 Bogdan Constantinescu <bog.con.bc at gmail.com>
+Brad Higgins <brad at defined.net>
 Brian Hendriks <brian at dolthub.com>
 Bulat Gaifullin <gaifullinbf at gmail.com>
 Caine Jette <jette at alum.mit.edu>
@@ -134,6 +135,7 @@ Ziheng Lyu <zihenglv at gmail.com>
 
 Barracuda Networks, Inc.
 Counting Ltd.
+Defined Networking Inc.
 DigitalOcean Inc.
 Dolthub Inc.
 dyves labs AG
diff --git a/transaction.go b/transaction.go
index 4a4b61001..8c502f49e 100644
--- a/transaction.go
+++ b/transaction.go
@@ -13,18 +13,32 @@ type mysqlTx struct {
 }
 
 func (tx *mysqlTx) Commit() (err error) {
-	if tx.mc == nil || tx.mc.closed.Load() {
+	if tx.mc == nil {
 		return ErrInvalidConn
 	}
+	if tx.mc.closed.Load() {
+		err = tx.mc.error()
+		if err == nil {
+			err = ErrInvalidConn
+		}
+		return
+	}
 	err = tx.mc.exec("COMMIT")
 	tx.mc = nil
 	return
 }
 
 func (tx *mysqlTx) Rollback() (err error) {
-	if tx.mc == nil || tx.mc.closed.Load() {
+	if tx.mc == nil {
 		return ErrInvalidConn
 	}
+	if tx.mc.closed.Load() {
+		err = tx.mc.error()
+		if err == nil {
+			err = ErrInvalidConn
+		}
+		return
+	}
 	err = tx.mc.exec("ROLLBACK")
 	tx.mc = nil
 	return