From 2ba27115cd7f53cfd7062cd9ccbac67dcc14305e Mon Sep 17 00:00:00 2001
From: xiongjiwei <xiongjiwei1996@outlook.com>
Date: Wed, 24 Nov 2021 15:21:00 +0800
Subject: [PATCH] rebase and add more test

---
 expression/builtin_convert_charset.go | 7 ++++---
 expression/collation.go               | 2 +-
 expression/constant_test.go           | 7 +++----
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/expression/builtin_convert_charset.go b/expression/builtin_convert_charset.go
index 83a92199a6521..aac9d1680ddda 100644
--- a/expression/builtin_convert_charset.go
+++ b/expression/builtin_convert_charset.go
@@ -226,7 +226,7 @@ func (b *builtinInternalFromBinarySig) getTransferFunc() func([]byte) ([]byte, e
 	return transferString
 }
 
-// BuildToBinaryFunction to_binary function.
+// BuildToBinaryFunction builds to_binary function.
 func BuildToBinaryFunction(ctx sessionctx.Context, expr Expression) (res Expression) {
 	fc := &tidbToBinaryFunctionClass{baseFunctionClass{InternalFuncToBinary, 1, 1}}
 	f, err := fc.getFunction(ctx, []Expression{expr})
@@ -241,7 +241,7 @@ func BuildToBinaryFunction(ctx sessionctx.Context, expr Expression) (res Express
 	return FoldConstant(res)
 }
 
-// BuildFromBinaryFunction build from_binary function.
+// BuildFromBinaryFunction builds from_binary function.
 func BuildFromBinaryFunction(ctx sessionctx.Context, expr Expression, tp *types.FieldType) (res Expression) {
 	fc := &tidbFromBinaryFunctionClass{baseFunctionClass{InternalFuncFromBinary, 1, 1}, tp}
 	f, err := fc.getFunction(ctx, []Expression{expr})
@@ -271,7 +271,8 @@ func HandleBinaryLiteral(ctx sessionctx.Context, expr Expression, ec *ExprCollat
 			ft.Charset, ft.Collate = ec.Charset, ec.Collation
 			return BuildFromBinaryFunction(ctx, expr, ft)
 		}
-	case ast.Hex, ast.Length, ast.OctetLength, ast.ASCII, ast.ToBase64:
+	case ast.Hex, ast.Length, ast.OctetLength, ast.ASCII, ast.ToBase64, ast.AesDecrypt, ast.Decode, ast.Encode,
+		ast.PasswordFunc, ast.MD5, ast.SHA, ast.SHA1, ast.SHA2, ast.Compress:
 		if _, err := charset.GetDefaultCollationLegacy(expr.GetType().Charset); err != nil {
 			return BuildToBinaryFunction(ctx, expr)
 		}
diff --git a/expression/collation.go b/expression/collation.go
index cb83f2c50505b..80a2720c8cfe4 100644
--- a/expression/collation.go
+++ b/expression/collation.go
@@ -301,7 +301,7 @@ func safeConvert(ctx sessionctx.Context, ec *ExprCollation, args ...Expression)
 			continue
 		}
 
-		// if value has ASCII repertoire, or it is binary string, just skip it.
+		// If value has ASCII repertoire, or it is binary string, just skip it.
 		if arg.Repertoire() == ASCII || types.IsBinaryStr(arg.GetType()) {
 			continue
 		}
diff --git a/expression/constant_test.go b/expression/constant_test.go
index fa38c19252061..62f03140b61f7 100644
--- a/expression/constant_test.go
+++ b/expression/constant_test.go
@@ -254,14 +254,13 @@ func TestConstantFoldingCharsetConvert(t *testing.T) {
 				newString("中文", "binary"))),
 			result: "中文",
 		},
+		// The result is binary charset, so gbk constant will convert to binary which is \xd6\xd0\xce\xc4.
 		{
 			condition: newFunction(ast.Concat,
-				newFunctionWithType(
-					InternalFuncFromBinary, types.NewFieldTypeWithCollation(mysql.TypeVarchar, "gbk_bin", -1),
-					newString("\xd2\xbb", "binary")),
 				newString("中文", "gbk_bin"),
+				newString("\xd2\xbb", "binary"),
 			),
-			result: "一中文",
+			result: "\xd6\xd0\xce\xc4\xd2\xbb",
 		},
 	}
 	for _, tt := range tests {