planner: fix the panic when we calculate the partition range (#23651)

planner/core/partition_pruner_test.go

@@ -0,0 +1,66 @@
+// Copyright 2019 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package core_test
+
+import (
+	"fmt"
+
+	. "github.com/pingcap/check"
+	"github.com/pingcap/tidb/domain"
+	"github.com/pingcap/tidb/kv"
+	"github.com/pingcap/tidb/sessionctx"
+	"github.com/pingcap/tidb/util/mock"
+	"github.com/pingcap/tidb/util/testkit"
+	"github.com/pingcap/tidb/util/testutil"
+)
+
+var _ = Suite(&testPartitionPruneSuit{})
+
+type testPartitionPruneSuit struct {
+	store    kv.Storage
+	dom      *domain.Domain
+	ctx      sessionctx.Context
+	testData testutil.TestData
+}
+
+func (s *testPartitionPruneSuit) cleanEnv(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test_partition")
+	r := tk.MustQuery("show tables")
+	for _, tb := range r.Rows() {
+		tableName := tb[0]
+		tk.MustExec(fmt.Sprintf("drop table %v", tableName))
+	}
+}
+
+func (s *testPartitionPruneSuit) SetUpSuite(c *C) {
+	var err error
+	s.store, s.dom, err = newStoreWithBootstrap()
+	c.Assert(err, IsNil)
+	s.ctx = mock.NewContext()
+}
+
+func (s *testPartitionPruneSuit) TearDownSuite(c *C) {
+	s.dom.Close()
+	s.store.Close()
+}
+
+func (s *testPartitionPruneSuit) TestIssue23622(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("USE test;")
+	tk.MustExec("drop table if exists t2;")
+	tk.MustExec("create table t2 (a int, b int) partition by range (a) (partition p0 values less than (0), partition p1 values less than (5));")
+	tk.MustExec("insert into t2(a) values (-1), (1);")
+	tk.MustQuery("select * from t2 where a > 10 or b is NULL order by a;").Check(testkit.Rows("-1 <nil>", "1 <nil>"))
+}

planner/core/rule_partition_processor.go

@@ -266,6 +266,10 @@ func (or partitionRangeOR) union(x partitionRangeOR) partitionRangeOR {
 }
 
 func (or partitionRangeOR) simplify() partitionRangeOR {
+	// if the length of the `or` is zero. We should return early.
+	if len(or) == 0 {
+		return or
+	}
 	// Make the ranges order by start.
 	sort.Sort(or)
 	sorted := or