fix wrong flen in cast functions (#19020)

pingcap · Aug 30, 2020 · a363130 · a363130
1 parent b7682ae
commit a363130
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Showing 2 changed files with 6 additions and 2 deletions.
diff --git a/expression/builtin_cast.go b/expression/builtin_cast.go
@@ -1778,6 +1778,10 @@ func BuildCastFunction(ctx sessionctx.Context, expr Expression, tp *types.FieldT
 		return expr
 	}
 
+	if tp.Flen == types.UnspecifiedLength {
+		tp.Flen = expr.GetType().Flen
+	}
+
 	var fc functionClass
 	switch tp.EvalType() {
 	case types.ETInt:

diff --git a/expression/typeinfer_test.go b/expression/typeinfer_test.go
@@ -181,9 +181,9 @@ func (s *testInferTypeSuite) createTestCase4Constants() []typeInferTestCase {
 
 func (s *testInferTypeSuite) createTestCase4Cast() []typeInferTestCase {
 	return []typeInferTestCase{
-		{"CAST(c_int_d AS BINARY)", mysql.TypeVarString, charset.CharsetBin, mysql.BinaryFlag, -1, -1}, // TODO: Flen should be 11.
+		{"CAST(c_int_d AS BINARY)", mysql.TypeVarString, charset.CharsetBin, mysql.BinaryFlag, 11, -1},
 		{"CAST(c_int_d AS BINARY(5))", mysql.TypeString, charset.CharsetBin, mysql.BinaryFlag, 5, -1},
-		{"CAST(c_int_d AS CHAR)", mysql.TypeVarString, charset.CharsetUTF8MB4, 0, -1, -1}, // TODO: Flen should be 11.
+		{"CAST(c_int_d AS CHAR)", mysql.TypeVarString, charset.CharsetUTF8MB4, 0, 11, -1},
 		{"CAST(c_int_d AS CHAR(5))", mysql.TypeVarString, charset.CharsetUTF8MB4, 0, 5, -1},
 		{"CAST(c_int_d AS DATE)", mysql.TypeDate, charset.CharsetBin, mysql.BinaryFlag, 10, 0},
 		{"CAST(c_int_d AS DATETIME)", mysql.TypeDatetime, charset.CharsetBin, mysql.BinaryFlag, 19, 0},