From b06eef79d0f294af319455a59b1341d539282307 Mon Sep 17 00:00:00 2001
From: Weizhen Wang <wangweizhen@pingcap.com>
Date: Thu, 29 Jan 2026 12:40:35 +0800
Subject: [PATCH 1/3] Defend against driver buffer reuse

---
 src/main.go | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/main.go b/src/main.go
index b93b2a5..72e78db 100644
--- a/src/main.go
+++ b/src/main.go
@@ -976,6 +976,16 @@ func dumpToByteRows(rows *sql.Rows) ([]*byteRows, error) {
 				return nil, errors.Trace(err)
 			}
 
+			for i, col := range tmp {
+				if col == nil {
+					continue
+				}
+				// Defensive copy to avoid driver buffer reuse corrupting large results.
+				copied := make([]byte, len(col))
+				copy(copied, col)
+				tmp[i] = copied
+			}
+
 			data = append(data, byteRow{tmp})
 		}
 

From 34c28db587ac68fd6c4be00a22e2efc063261bbd Mon Sep 17 00:00:00 2001
From: Weizhen Wang <wangweizhen@pingcap.com>
Date: Thu, 29 Jan 2026 13:58:32 +0800
Subject: [PATCH 2/3] Truncate long SQL in error logs

---
 src/main.go | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/main.go b/src/main.go
index 72e78db..ddcac5a 100644
--- a/src/main.go
+++ b/src/main.go
@@ -16,6 +16,7 @@ package main
 import (
 	"bytes"
 	"context"
+	"crypto/sha256"
 	"database/sql"
 	"flag"
 	"fmt"
@@ -361,6 +362,23 @@ func (t *tester) addSuccess(testSuite *XUnitTestSuite, startTime *time.Time, cnt
 	})
 }
 
+func formatSQLForLog(sql string) string {
+	const maxLen = 1024
+	if len(sql) <= maxLen {
+		return sql
+	}
+	const headLen = 256
+	const tailLen = 256
+	sum := sha256.Sum256([]byte(sql))
+	head := sql[:headLen]
+	tail := sql[len(sql)-tailLen:]
+	head = strings.ReplaceAll(head, "\n", " ")
+	head = strings.ReplaceAll(head, "\r", " ")
+	tail = strings.ReplaceAll(tail, "\n", " ")
+	tail = strings.ReplaceAll(tail, "\r", " ")
+	return fmt.Sprintf("len=%d sha256=%x head=%q tail=%q", len(sql), sum, head, tail)
+}
+
 func (t *tester) Run() error {
 	t.preProcess()
 	defer t.postProcess()
@@ -443,7 +461,7 @@ func (t *tester) Run() error {
 			if t.enableConcurrent {
 				concurrentQueue = append(concurrentQueue, q)
 			} else if err = t.execute(q); err != nil {
-				err = errors.Annotate(err, fmt.Sprintf("sql:%v", q.Query))
+				err = errors.Annotate(err, fmt.Sprintf("sql:%s", formatSQLForLog(q.Query)))
 				t.addFailure(&testSuite, &err, testCnt)
 				return err
 			}

From b5ecc7b65a5a725174019a46a00001aef359aa98 Mon Sep 17 00:00:00 2001
From: Weizhen Wang <wangweizhen@pingcap.com>
Date: Thu, 29 Jan 2026 17:49:53 +0800
Subject: [PATCH 3/3] Preserve newlines in log formatter

---
 src/color.go | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/color.go b/src/color.go
index 0e0ae5d..8adf20a 100644
--- a/src/color.go
+++ b/src/color.go
@@ -48,15 +48,20 @@ func shouldUseColor() bool {
 }
 
 func configureLogging() {
+	base := &log.TextFormatter{DisableQuote: true}
 	switch normalizeColorMode(colorMode) {
 	case colorModeAlways:
-		log.SetFormatter(&log.TextFormatter{ForceColors: true})
+		base.ForceColors = true
+		log.SetFormatter(base)
 	case colorModeNever:
-		log.SetFormatter(&log.TextFormatter{DisableColors: true})
+		base.DisableColors = true
+		log.SetFormatter(base)
 	case colorModeAuto:
-		// Use logrus default auto behavior.
+		// Use logrus default auto behavior with DisableQuote enabled.
+		log.SetFormatter(base)
 	default:
-		log.SetFormatter(&log.TextFormatter{ForceColors: true})
+		base.ForceColors = true
+		log.SetFormatter(base)
 	}
 }