ddl: fix "wrong warning messages when running some DDL jobs"

ddl/ddl.go

@@ -1094,8 +1094,13 @@ func (d *ddl) DoDDLJob(ctx sessionctx.Context, job *model.Job) error {
 					logutil.BgLogger().Info("[ddl] DDL warnings doesn't match the warnings count", zap.Int64("jobID", jobID))
 				} else {
 					for key, warning := range historyJob.ReorgMeta.Warnings {
-						for j := int64(0); j < historyJob.ReorgMeta.WarningsCount[key]; j++ {
+						keyCount := historyJob.ReorgMeta.WarningsCount[key]
+						if keyCount == 1 {
 							ctx.GetSessionVars().StmtCtx.AppendWarning(warning)
+						} else {
+							newMsg := fmt.Sprintf("%d warnings with this error code, first warning: "+warning.GetMsg(), keyCount)
+							newWarning := dbterror.ClassTypes.Synthesize(terror.ErrCode(warning.Code()), newMsg)
+							ctx.GetSessionVars().StmtCtx.AppendWarning(newWarning)
 						}
 					}
 				}

ddl/failtest/fail_db_test.go

@@ -18,6 +18,7 @@ import (
 	"context"
 	"fmt"
 	"math/rand"
+	"strings"
 	"sync/atomic"
 	"testing"
 	"time"
@@ -532,6 +533,34 @@ func TestModifyColumn(t *testing.T) {
 	tk.MustExec("drop table t, t2, t3, t4, t5")
 }
 
+func TestIssue38699(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+
+	//Test multi records
+	tk.MustExec("USE test")
+	tk.MustExec("set sql_mode=''")
+	tk.MustExec("DROP TABLE IF EXISTS t;")
+	tk.MustExec("CREATE TABLE t (a int)")
+	tk.MustExec("insert into t values (1000000000), (2000000)")
+	tk.MustExec("alter table t modify a tinyint")
+	result := tk.MustQuery("show warnings")
+	require.Len(t, result.Rows(), 1)
+	result.CheckWithFunc(testkit.Rows("Warning 1690 2 warnings with this error code"), func(actual []string, expected []interface{}) bool {
+		//Check if it starts with x warning(s)
+		return strings.EqualFold(actual[0], expected[0].(string)) && strings.EqualFold(actual[1], expected[1].(string)) && strings.HasPrefix(actual[2], expected[2].(string))
+	})
+
+	//Test single record
+	tk.MustExec("DROP TABLE IF EXISTS t;")
+	tk.MustExec("CREATE TABLE t (a int)")
+	tk.MustExec("insert into t values (1000000000)")
+	tk.MustExec("alter table t modify a tinyint")
+	result = tk.MustQuery("show warnings")
+	require.Len(t, result.Rows(), 1)
+	result.Check(testkit.Rows("Warning 1690 constant 1000000000 overflows tinyint"))
+}
+
 func TestPartitionAddPanic(t *testing.T) {
 	s := createFailDBSuite(t)
 	tk := testkit.NewTestKit(t, s.store)

ddl/modify_column_test.go

@@ -813,10 +813,7 @@ func TestModifyColumnTypeWithWarnings(t *testing.T) {
 	// 111.22 will be truncated the fraction .22 as .2 with truncated warning for each row.
 	tk.MustExec("alter table t modify column a decimal(4,1)")
 	// there should 4 rows of warnings corresponding to the origin rows.
-	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1292 Truncated incorrect DECIMAL value: '111.22'",
-		"Warning 1292 Truncated incorrect DECIMAL value: '111.22'",
-		"Warning 1292 Truncated incorrect DECIMAL value: '111.22'",
-		"Warning 1292 Truncated incorrect DECIMAL value: '111.22'"))
+	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1292 4 warnings with this error code, first warning: Truncated incorrect DECIMAL value: '111.22'"))
 
 	// Test the strict warnings is treated as errors under the strict mode.
 	tk.MustExec("drop table if exists t")
@@ -829,9 +826,7 @@ func TestModifyColumnTypeWithWarnings(t *testing.T) {
 	// Test the strict warnings is treated as warnings under the non-strict mode.
 	tk.MustExec("set @@sql_mode=\"\"")
 	tk.MustExec("alter table t modify column a decimal(3,1)")
-	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1690 DECIMAL value is out of range in '(3, 1)'",
-		"Warning 1690 DECIMAL value is out of range in '(3, 1)'",
-		"Warning 1690 DECIMAL value is out of range in '(3, 1)'"))
+	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1690 3 warnings with this error code, first warning: DECIMAL value is out of range in '(3, 1)'"))
 }
 
 // TestModifyColumnTypeWhenInterception is to test modifying column type with warnings intercepted by
@@ -895,5 +890,5 @@ func TestModifyColumnTypeWhenInterception(t *testing.T) {
 	require.True(t, checkMiddleAddedCount)
 
 	res := tk.MustQuery("show warnings")
-	require.Len(t, res.Rows(), count)
+	require.Len(t, res.Rows(), 1)
 }