From 2f4ff9bd6b820dfddf23fa7eee8e908c2cb1a017 Mon Sep 17 00:00:00 2001
From: xhe <xw897002528@gmail.com>
Date: Fri, 4 Sep 2020 09:42:49 +0800
Subject: [PATCH] types: fix year conversion

---
 types/convert_test.go | 16 ++++++++++++++++
 types/datum.go        |  7 +++++--
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/types/convert_test.go b/types/convert_test.go
index 4b898f82bf007..7d5147f0f7de0 100644
--- a/types/convert_test.go
+++ b/types/convert_test.go
@@ -687,10 +687,26 @@ func (s *testTypeConvertSuite) TestConvert(c *C) {
 	signedAccept(c, mysql.TypeYear, 1901, "1901")
 	signedAccept(c, mysql.TypeYear, 1900.567, "1901")
 	signedDeny(c, mysql.TypeYear, 1900.456, "0")
+	signedAccept(c, mysql.TypeYear, 0, "0")
+	signedAccept(c, mysql.TypeYear, "0", "2000")
+	signedAccept(c, mysql.TypeYear, "00", "2000")
+	signedAccept(c, mysql.TypeYear, " 0", "2000")
+	signedAccept(c, mysql.TypeYear, " 00", "2000")
+	signedAccept(c, mysql.TypeYear, " 000", "0")
+	signedAccept(c, mysql.TypeYear, " 0000 ", "2000")
+	signedAccept(c, mysql.TypeYear, " 0ab", "0")
+	signedAccept(c, mysql.TypeYear, "00bc", "0")
+	signedAccept(c, mysql.TypeYear, "000a", "0")
+	signedAccept(c, mysql.TypeYear, " 000a ", "2000")
 	signedAccept(c, mysql.TypeYear, 1, "2001")
+	signedAccept(c, mysql.TypeYear, "1", "2001")
+	signedAccept(c, mysql.TypeYear, "01", "2001")
 	signedAccept(c, mysql.TypeYear, 69, "2069")
+	signedAccept(c, mysql.TypeYear, "69", "2069")
 	signedAccept(c, mysql.TypeYear, 70, "1970")
+	signedAccept(c, mysql.TypeYear, "70", "1970")
 	signedAccept(c, mysql.TypeYear, 99, "1999")
+	signedAccept(c, mysql.TypeYear, "99", "1999")
 	signedDeny(c, mysql.TypeYear, 100, "0")
 	signedDeny(c, mysql.TypeYear, "99999999999999999999999999999999999", "0")
 
diff --git a/types/datum.go b/types/datum.go
index 106568a9f8b7a..87ca8558a79b9 100644
--- a/types/datum.go
+++ b/types/datum.go
@@ -1333,12 +1333,15 @@ func (d *Datum) convertToMysqlYear(sc *stmtctx.StatementContext, target *FieldTy
 	switch d.k {
 	case KindString, KindBytes:
 		s := d.GetString()
-		y, err = StrToInt(sc, s, false)
+		trimS := strings.TrimSpace(s)
+		y, err = StrToInt(sc, trimS, false)
 		if err != nil {
 			ret.SetInt64(0)
 			return ret, errors.Trace(err)
 		}
-		if len(s) != 4 && len(s) > 0 && s[0:1] == "0" {
+		// condition:
+		// parsed to 0, not a string of length 4, the first valid char is a 0 digit
+		if len(s) != 4 && y == 0 && strings.HasPrefix(trimS, "0") {
 			adjust = true
 		}
 	case KindMysqlTime: