From db7e6c59ad31832ace1b70e4c716d5b83637c3ca Mon Sep 17 00:00:00 2001
From: HuaiyuXu <391585975@qq.com>
Date: Tue, 20 Mar 2018 19:02:32 +0800
Subject: [PATCH] *: check float/double display width and scale (#6098)

---
 mysql/const.go          |  8 ++------
 parser/parser.y         |  2 +-
 plan/preprocess.go      | 11 +++++++----
 plan/preprocess_test.go | 11 +++++++----
 4 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/mysql/const.go b/mysql/const.go
index 5f3b84f8be4c7..7a37e3e0c2871 100644
--- a/mysql/const.go
+++ b/mysql/const.go
@@ -227,6 +227,8 @@ const (
 
 	MaxIntWidth             = 20
 	MaxRealWidth            = 23
+	MaxFloatingTypeScale    = 30
+	MaxFloatingTypeWidth    = 255
 	MaxDecimalScale         = 30
 	MaxDecimalWidth         = 65
 	MaxDateWidth            = 10 // YYYY-MM-DD.
@@ -244,12 +246,6 @@ const (
 	MaxFieldVarCharLength = 65535
 )
 
-// MySQL precision.
-const (
-	PrecisionForDouble = 53
-	PrecisionForFloat  = 24
-)
-
 // MaxTypeSetMembers is the number of set members.
 const MaxTypeSetMembers = 64
 
diff --git a/parser/parser.y b/parser/parser.y
index 6fbda5acd5e2b..a865fcb660013 100644
--- a/parser/parser.y
+++ b/parser/parser.y
@@ -5532,7 +5532,7 @@ NumericType:
 		x := types.NewFieldType($1.(byte))
 		x.Flen = fopt.Flen
 		if x.Tp == mysql.TypeFloat {
-			if x.Flen > mysql.PrecisionForFloat {
+			if x.Flen > 24 {
 				x.Tp = mysql.TypeDouble
 			}
 		}
diff --git a/plan/preprocess.go b/plan/preprocess.go
index a6305beb4ad33..c3069e1cc1779 100644
--- a/plan/preprocess.go
+++ b/plan/preprocess.go
@@ -408,9 +408,12 @@ func checkColumn(colDef *ast.ColumnDef) error {
 		if tp.Flen != types.UnspecifiedLength && tp.Flen > maxFlen {
 			return types.ErrTooBigFieldLength.Gen("Column length too big for column '%s' (max = %d); use BLOB or TEXT instead", colDef.Name.Name.O, maxFlen)
 		}
-	case mysql.TypeDouble:
-		if tp.Flen != types.UnspecifiedLength && tp.Flen > mysql.PrecisionForDouble {
-			return types.ErrWrongFieldSpec.Gen("Incorrect column specifier for column '%s'", colDef.Name.Name.O)
+	case mysql.TypeFloat, mysql.TypeDouble:
+		if tp.Decimal > mysql.MaxFloatingTypeScale {
+			return types.ErrTooBigScale.GenByArgs(tp.Decimal, colDef.Name.Name.O, mysql.MaxFloatingTypeScale)
+		}
+		if tp.Flen > mysql.MaxFloatingTypeWidth {
+			return types.ErrTooBigPrecision.GenByArgs(tp.Flen, colDef.Name.Name.O, mysql.MaxFloatingTypeWidth)
 		}
 	case mysql.TypeSet:
 		if len(tp.Elems) > mysql.MaxTypeSetMembers {
@@ -436,7 +439,7 @@ func checkColumn(colDef *ast.ColumnDef) error {
 	return nil
 }
 
-// isNowSymFunc checks whether defaul value is a NOW() builtin function.
+// isNowSymFunc checks whether default value is a NOW() builtin function.
 func isDefaultValNowSymFunc(expr ast.ExprNode) bool {
 	if funcCall, ok := expr.(*ast.FuncCallExpr); ok {
 		// Default value NOW() is transformed to CURRENT_TIMESTAMP() in parser.
diff --git a/plan/preprocess_test.go b/plan/preprocess_test.go
index bedbd4ceda27e..e6ff75012d473 100644
--- a/plan/preprocess_test.go
+++ b/plan/preprocess_test.go
@@ -97,10 +97,6 @@ func (s *testValidatorSuite) TestValidator(c *C) {
 			errors.New("[types:1439]Display width out of range for column 'c' (max = 4294967295)")},
 		{"alter table t add column c float(4294967296)", true,
 			errors.New("[types:1439]Display width out of range for column 'c' (max = 4294967295)")},
-		{"create table t (c float(54))", true,
-			errors.New("[types:1063]Incorrect column specifier for column 'c'")},
-		{"alter table t add column c float(54)", true,
-			errors.New("[types:1063]Incorrect column specifier for column 'c'")},
 		{"create table t (set65 set ('1','2','3','4','5','6','7','8','9','10','11','12','13','14','15','16','17','18','19','20','21','22','23','24','25','26','27','28','29','30','31','32','33','34','35','36','37','38','39','40','41','42','43','44','45','46','47','48','49','50','51','52','53','54','55','56','57','58','59','60','61','62','63','64','65'))", true,
 			errors.New("[types:1097]Too many strings for column set65 and SET")},
 		{"alter table t add column set65 set ('1','2','3','4','5','6','7','8','9','10','11','12','13','14','15','16','17','18','19','20','21','22','23','24','25','26','27','28','29','30','31','32','33','34','35','36','37','38','39','40','41','42','43','44','45','46','47','48','49','50','51','52','53','54','55','56','57','58','59','60','61','62','63','64','65')", true,
@@ -172,6 +168,13 @@ func (s *testValidatorSuite) TestValidator(c *C) {
 		{"alter table t modify column a DECIMAL(66,30);", false, types.ErrTooBigPrecision},
 		{"alter table t modify column a DECIMAL(65,31);", false, types.ErrTooBigScale},
 		{"alter table t modify column a DECIMAL(65,30);", true, nil},
+
+		{"CREATE TABLE t (a float(255, 30))", true, nil},
+		{"CREATE TABLE t (a double(255, 30))", true, nil},
+		{"CREATE TABLE t (a float(256, 30))", false, types.ErrTooBigPrecision},
+		{"CREATE TABLE t (a float(255, 31))", false, types.ErrTooBigScale},
+		{"CREATE TABLE t (a double(256, 30))", false, types.ErrTooBigPrecision},
+		{"CREATE TABLE t (a double(255, 31))", false, types.ErrTooBigScale},
 	}
 
 	store, dom, err := newStoreWithBootstrap()