planner/core: raise 'No database selected' error for grant statement (p…

…ingcap#13745)

planner/core/integration_test.go

@@ -15,9 +15,11 @@ package core_test
 
 import (
 	. "github.com/pingcap/check"
+	"github.com/pingcap/errors"
 	"github.com/pingcap/parser/mysql"
 	"github.com/pingcap/tidb/domain"
 	"github.com/pingcap/tidb/kv"
+	"github.com/pingcap/tidb/planner/core"
 	"github.com/pingcap/tidb/util/testkit"
 	"github.com/pingcap/tidb/util/testutil"
 )
@@ -281,3 +283,12 @@ func (s *testIntegrationSuite) TestPartitionTableStats(c *C) {
 		tk.MustQuery(tt).Check(testkit.Rows(output[i].Result...))
 	}
 }
+
+func (s *testIntegrationSuite) TestErrNoDB(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("create user test")
+	_, err := tk.Exec("grant select on test1111 to test@'%'")
+	c.Assert(errors.Cause(err), Equals, core.ErrNoDB)
+	tk.MustExec("use test")
+	tk.MustExec("grant select on test1111 to test@'%'")
+}

planner/core/planbuilder.go

@@ -1607,6 +1607,11 @@ func (b *PlanBuilder) buildSimple(node ast.StmtNode) (Plan, error) {
 		err := ErrSpecificAccessDenied.GenWithStackByArgs("CREATE USER")
 		b.visitInfo = appendVisitInfo(b.visitInfo, mysql.CreateUserPriv, "", "", "", err)
 	case *ast.GrantStmt:
+		if b.ctx.GetSessionVars().CurrentDB == "" && raw.Level.DBName == "" {
+			if raw.Level.Level == ast.GrantLevelTable {
+				return nil, ErrNoDB
+			}
+		}
 		b.visitInfo = collectVisitInfoFromGrantStmt(b.ctx, b.visitInfo, raw)
 	case *ast.GrantRoleStmt:
 		err := ErrSpecificAccessDenied.GenWithStackByArgs("GRANT ROLE")