From 3c46a1e072caab295a5fc36e7f18a58175d3cf79 Mon Sep 17 00:00:00 2001
From: xhe <xw897002528@gmail.com>
Date: Mon, 1 Jul 2024 18:22:29 +0800
Subject: [PATCH] *: panic guard for warnings (#54043)

close pingcap/tidb#48756
---
 pkg/executor/show.go                        |  6 +++++-
 pkg/executor/test/executor/executor_test.go | 19 +++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/pkg/executor/show.go b/pkg/executor/show.go
index de0b8f9657827..d8d001992b703 100644
--- a/pkg/executor/show.go
+++ b/pkg/executor/show.go
@@ -1887,7 +1887,11 @@ func (e *ShowExec) fetchShowWarnings(errOnly bool) error {
 			sqlErr := terror.ToSQLError(x)
 			e.appendRow([]any{w.Level, int64(sqlErr.Code), sqlErr.Message})
 		default:
-			e.appendRow([]any{w.Level, int64(mysql.ErrUnknown), warn.Error()})
+			var err string
+			if warn != nil {
+				err = warn.Error()
+			}
+			e.appendRow([]any{w.Level, int64(mysql.ErrUnknown), err})
 		}
 	}
 	return nil
diff --git a/pkg/executor/test/executor/executor_test.go b/pkg/executor/test/executor/executor_test.go
index 365b154841a2c..46339514352ed 100644
--- a/pkg/executor/test/executor/executor_test.go
+++ b/pkg/executor/test/executor/executor_test.go
@@ -2928,3 +2928,22 @@ func TestDecimalDivPrecisionIncrement(t *testing.T) {
 	tk.MustExec("set div_precision_increment = 10")
 	tk.MustQuery("select avg(a/b) from t").Check(testkit.Rows("1.21428571428571428550"))
 }
+
+func TestIssue48756(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("CREATE TABLE t (id INT, a VARBINARY(20), b BIGINT)")
+	tk.MustExec(`INSERT INTO t VALUES(1, _binary '2012-05-19 09:06:07', 20120519090607),
+(1, _binary '2012-05-19 09:06:07', 20120519090607),
+(2, _binary '12012-05-19 09:06:07', 120120519090607),
+(2, _binary '12012-05-19 09:06:07', 120120519090607)`)
+	tk.MustQuery("SELECT SUBTIME(BIT_OR(b), '1 1:1:1.000002') FROM t GROUP BY id").Sort().Check(testkit.Rows(
+		"2012-05-18 08:05:05.999998",
+		"<nil>",
+	))
+	tk.MustQuery("show warnings").Check(testkit.Rows(
+		"Warning 1292 Incorrect time value: '120120519090607'",
+		"Warning 1105 ",
+	))
+}