From 84750e85502f863626df02cfe2f5cb5637a6ce49 Mon Sep 17 00:00:00 2001
From: Zhang Jian <zjsariel@gmail.com>
Date: Tue, 12 Feb 2019 11:48:55 +0800
Subject: [PATCH] expression: handle ENUM in builtin function Values() (#9225)

---
 expression/builtin_other.go    | 21 +++++++++++++++------
 expression/column.go           | 10 +++-------
 expression/integration_test.go | 11 +++++++++++
 3 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/expression/builtin_other.go b/expression/builtin_other.go
index ce9b0bbb88136..4b8ff8d79c343 100644
--- a/expression/builtin_other.go
+++ b/expression/builtin_other.go
@@ -615,13 +615,22 @@ func (b *builtinValuesStringSig) evalString(_ chunk.Row) (string, bool, error) {
 	if row.IsEmpty() {
 		return "", true, errors.New("Session current insert values is nil")
 	}
-	if b.offset < row.Len() {
-		if row.IsNull(b.offset) {
-			return "", true, nil
-		}
-		return row.GetString(b.offset), false, nil
+	if b.offset >= row.Len() {
+		return "", true, errors.Errorf("Session current insert values len %d and column's offset %v don't match", row.Len(), b.offset)
 	}
-	return "", true, errors.Errorf("Session current insert values len %d and column's offset %v don't match", row.Len(), b.offset)
+
+	if row.IsNull(b.offset) {
+		return "", true, nil
+	}
+
+	// Specially handle the ENUM/SET/BIT input value.
+	if retType := b.getRetTp(); retType.Hybrid() {
+		val := row.GetDatum(b.offset, retType)
+		res, err := val.ToString()
+		return res, err != nil, err
+	}
+
+	return row.GetString(b.offset), false, nil
 }
 
 type builtinValuesTimeSig struct {
diff --git a/expression/column.go b/expression/column.go
index 72fde92c19d00..d049017417fe6 100644
--- a/expression/column.go
+++ b/expression/column.go
@@ -231,18 +231,14 @@ func (col *Column) EvalString(ctx sessionctx.Context, row chunk.Row) (string, bo
 	if row.IsNull(col.Index) {
 		return "", true, nil
 	}
+
+	// Specially handle the ENUM/SET/BIT input value.
 	if col.GetType().Hybrid() {
 		val := row.GetDatum(col.Index, col.RetType)
-		if val.IsNull() {
-			return "", true, nil
-		}
 		res, err := val.ToString()
-		resLen := len([]rune(res))
-		if ctx.GetSessionVars().StmtCtx.PadCharToFullLength && col.GetType().Tp == mysql.TypeString && resLen < col.RetType.Flen {
-			res = res + strings.Repeat(" ", col.RetType.Flen-resLen)
-		}
 		return res, err != nil, err
 	}
+
 	val := row.GetString(col.Index)
 	if ctx.GetSessionVars().StmtCtx.PadCharToFullLength && col.GetType().Tp == mysql.TypeString {
 		valLen := len([]rune(val))
diff --git a/expression/integration_test.go b/expression/integration_test.go
index bbf019e567a38..31e9e778b8b8d 100644
--- a/expression/integration_test.go
+++ b/expression/integration_test.go
@@ -3898,3 +3898,14 @@ func (s *testIntegrationSuite) TestValuesFloat32(c *C) {
 	tk.MustExec(`insert into t values (1, 0.02) on duplicate key update j = values (j);`)
 	tk.MustQuery(`select * from t;`).Check(testkit.Rows(`1 0.02`))
 }
+
+func (s *testIntegrationSuite) TestValuesEnum(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec(`drop table if exists t;`)
+	tk.MustExec(`create table t (a bigint primary key, b enum('a','b','c'));`)
+	tk.MustExec(`insert into t values (1, "a");`)
+	tk.MustQuery(`select * from t;`).Check(testkit.Rows(`1 a`))
+	tk.MustExec(`insert into t values (1, "b") on duplicate key update b = values(b);`)
+	tk.MustQuery(`select * from t;`).Check(testkit.Rows(`1 b`))
+}