planner: Do not allow variables in create view (#57474) (#59323)

close #53176

cmd/explaintest/r/ddl.result

@@ -0,0 +1,8 @@
+create view sql_mode_view as select @@sql_mode;
+Error 1351: View's SELECT contains a variable or parameter
+create view sql_mode_view as select @@global.sql_mode;
+Error 1351: View's SELECT contains a variable or parameter
+create view sql_mode_view as select @a;
+Error 1351: View's SELECT contains a variable or parameter
+create view sql_mode_view as select 1 where @a = 4;
+Error 1351: View's SELECT contains a variable or parameter

cmd/explaintest/t/ddl.test

@@ -0,0 +1,9 @@
+# issue 53176
+-- error 1351
+create view sql_mode_view as select @@sql_mode;
+-- error 1351
+create view sql_mode_view as select @@global.sql_mode;
+-- error 1351
+create view sql_mode_view as select @a;
+-- error 1351
+create view sql_mode_view as select 1 where @a = 4;

errors.toml

@@ -856,6 +856,11 @@ error = '''
 View's SELECT contains a '%s' clause
 '''
 
+["ddl:1351"]
+error = '''
+View's SELECT contains a variable or parameter
+'''
+
 ["ddl:1353"]
 error = '''
 In definition of view, derived table or common table expression, SELECT list and column names list have different column counts

executor/ddl_test.go

@@ -232,9 +232,8 @@ func TestCreateView(t *testing.T) {
 	// drop multiple views in a statement
 	tk.MustExec("drop view v1,v2,v3,v4,v5,v6")
 	// view with variable
-	tk.MustExec("create view v1 (c,d) as select a,b+@@global.max_user_connections from t1")
-	tk.MustGetErrMsg("create view v1 (c,d) as select a,b from t1 where a = @@global.max_user_connections", "[schema:1050]Table 'test.v1' already exists")
-	tk.MustExec("drop view v1")
+	tk.MustGetErrMsg("create view v1 (c,d) as select a,b+@@global.max_user_connections from t1", "[ddl:1351]View's SELECT contains a variable or parameter")
+	tk.MustGetErrMsg("create view v1 (c,d) as select a,b from t1 where a = @@global.max_user_connections", "[ddl:1351]View's SELECT contains a variable or parameter")
 	// view with different col counts
 	tk.MustGetErrCode("create view v1 (c,d,e) as select a,b from t1 ", errno.ErrViewWrongList)
 	tk.MustGetErrCode("create view v1 (c) as select a,b from t1 ", errno.ErrViewWrongList)

planner/core/planbuilder.go

@@ -4443,6 +4443,32 @@ func convertValueListToData(valueList []ast.ExprNode, handleColInfos []*model.Co
 	return data, nil
 }
 
+type userVariableChecker struct {
+	hasUserVariables bool
+}
+
+func (e *userVariableChecker) Enter(in ast.Node) (ast.Node, bool) {
+	if _, ok := in.(*ast.VariableExpr); ok {
+		e.hasUserVariables = true
+		return in, true
+	}
+	return in, false
+}
+
+func (*userVariableChecker) Leave(in ast.Node) (ast.Node, bool) {
+	return in, true
+}
+
+// Check for UserVariables
+func checkForUserVariables(in ast.Node) error {
+	v := &userVariableChecker{hasUserVariables: false}
+	_, ok := in.Accept(v)
+	if !ok || v.hasUserVariables {
+		return dbterror.ErrViewSelectVariable
+	}
+	return nil
+}
+
 func (b *PlanBuilder) buildDDL(ctx context.Context, node ast.DDLNode) (Plan, error) {
 	var authErr error
 	switch v := node.(type) {
@@ -4582,6 +4608,10 @@ func (b *PlanBuilder) buildDDL(ctx context.Context, node ast.DDLNode) (Plan, err
 				v.ReferTable.Name.L, "", authErr)
 		}
 	case *ast.CreateViewStmt:
+		err := checkForUserVariables(v.Select)
+		if err != nil {
+			return nil, err
+		}
 		b.isCreateView = true
 		b.capFlag |= canExpandAST | renameView
 		b.renamingViewName = v.ViewName.Schema.L + "." + v.ViewName.Name.L

util/dbterror/ddl_terror.go

@@ -222,6 +222,8 @@ var (
 	ErrErrorOnRename = ClassDDL.NewStd(mysql.ErrErrorOnRename)
 	// ErrViewSelectClause returns error for create view with select into clause
 	ErrViewSelectClause = ClassDDL.NewStd(mysql.ErrViewSelectClause)
+	// ErrViewSelectVariable returns error for create view with select into clause
+	ErrViewSelectVariable = ClassDDL.NewStd(mysql.ErrViewSelectVariable)
 
 	// ErrNotAllowedTypeInPartition returns not allowed type error when creating table partition with unsupported expression type.
 	ErrNotAllowedTypeInPartition = ClassDDL.NewStd(mysql.ErrFieldTypeNotAllowedAsPartitionField)