From 4ae5b0d3813d55f743f7e2928999c098c416b506 Mon Sep 17 00:00:00 2001
From: Dirkjan Bussink <d.bussink@gmail.com>
Date: Tue, 26 Dec 2023 18:25:51 +0100
Subject: [PATCH] evalengine: Fix week overflow (#14859)

Signed-off-by: Manan Gupta <manan@planetscale.com>
---
 go/mysql/datetime/datetime.go            |  8 ++++++++
 go/vt/vtgate/evalengine/compiler_test.go | 16 ++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/go/mysql/datetime/datetime.go b/go/mysql/datetime/datetime.go
index cc1fc92e091..73ae234e932 100644
--- a/go/mysql/datetime/datetime.go
+++ b/go/mysql/datetime/datetime.go
@@ -315,12 +315,16 @@ func (d Date) Week(mode int) int {
 		year, week := d.SundayWeek()
 		if year < d.Year() {
 			return 0
+		} else if year > d.Year() {
+			return 53
 		}
 		return week
 	case 1:
 		year, week := d.ISOWeek()
 		if year < d.Year() {
 			return 0
+		} else if year > d.Year() {
+			return 53
 		}
 		return week
 	case 2:
@@ -333,12 +337,16 @@ func (d Date) Week(mode int) int {
 		year, week := d.Sunday4DayWeek()
 		if year < d.Year() {
 			return 0
+		} else if year > d.Year() {
+			return 53
 		}
 		return week
 	case 5:
 		year, week := d.MondayWeek()
 		if year < d.Year() {
 			return 0
+		} else if year > d.Year() {
+			return 53
 		}
 		return week
 	case 6:
diff --git a/go/vt/vtgate/evalengine/compiler_test.go b/go/vt/vtgate/evalengine/compiler_test.go
index 06dd679920e..468d4737828 100644
--- a/go/vt/vtgate/evalengine/compiler_test.go
+++ b/go/vt/vtgate/evalengine/compiler_test.go
@@ -487,6 +487,22 @@ func TestCompilerSingle(t *testing.T) {
 			expression: `case when null is null then 23 else null end`,
 			result:     `INT64(23)`,
 		},
+		{
+			expression: `week('2023-12-31', 4)`,
+			result:     `INT64(53)`,
+		},
+		{
+			expression: `week('2023-12-31', 2)`,
+			result:     `INT64(53)`,
+		},
+		{
+			expression: `week('2024-12-31', 1)`,
+			result:     `INT64(53)`,
+		},
+		{
+			expression: `week('2024-12-31', 5)`,
+			result:     `INT64(53)`,
+		},
 	}
 
 	for _, tc := range testCases {