parser: apply feature-ids special comments to auto_random (#15412)

executor/show.go

@@ -813,7 +813,7 @@ func ConstructResultOfShowCreateTable(ctx sessionctx.Context, tableInfo *model.T
 			}
 		}
 		if tableInfo.PKIsHandle && tableInfo.ContainsAutoRandomBits() && tableInfo.GetPkName().L == col.Name.L {
-			buf.WriteString(fmt.Sprintf(" /*T!%s AUTO_RANDOM(%d) */", parser.CommentCodeAutoRandom, tableInfo.AutoRandomBits))
+			buf.WriteString(fmt.Sprintf(" /*T![auto_rand] AUTO_RANDOM(%d) */", tableInfo.AutoRandomBits))
 		}
 		if len(col.Comment) > 0 {
 			buf.WriteString(fmt.Sprintf(" COMMENT '%s'", format.OutputFormat(col.Comment)))

executor/show_test.go

@@ -663,7 +663,7 @@ func (s *testAutoRandomSuite) TestShowCreateTableAutoRandom(c *C) {
 	tk.MustQuery("show create table `auto_random_tbl1`").Check(testutil.RowsWithSep("|",
 		""+
 			"auto_random_tbl1 CREATE TABLE `auto_random_tbl1` (\n"+
-			"  `a` bigint(20) NOT NULL /*T!30100 AUTO_RANDOM(3) */,\n"+
+			"  `a` bigint(20) NOT NULL /*T![auto_rand] AUTO_RANDOM(3) */,\n"+
 			"  `b` varchar(255) DEFAULT NULL,\n"+
 			"  PRIMARY KEY (`a`)\n"+
 			") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin",
@@ -674,18 +674,18 @@ func (s *testAutoRandomSuite) TestShowCreateTableAutoRandom(c *C) {
 	tk.MustQuery("show create table auto_random_tbl2").Check(testutil.RowsWithSep("|",
 		""+
 			"auto_random_tbl2 CREATE TABLE `auto_random_tbl2` (\n"+
-			"  `a` bigint(20) NOT NULL /*T!30100 AUTO_RANDOM(5) */,\n"+
+			"  `a` bigint(20) NOT NULL /*T![auto_rand] AUTO_RANDOM(5) */,\n"+
 			"  `b` char(1) DEFAULT NULL,\n"+
 			"  PRIMARY KEY (`a`)\n"+
 			") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin",
 	))
 
 	// Special version comment can be shown in TiDB with new version.
-	tk.MustExec("create table auto_random_tbl3 (a bigint /*T!30100 auto_random */ primary key)")
+	tk.MustExec("create table auto_random_tbl3 (a bigint /*T![auto_rand] auto_random */ primary key)")
 	tk.MustQuery("show create table auto_random_tbl3").Check(testutil.RowsWithSep("|",
 		""+
 			"auto_random_tbl3 CREATE TABLE `auto_random_tbl3` (\n"+
-			"  `a` bigint(20) NOT NULL /*T!30100 AUTO_RANDOM(5) */,\n"+
+			"  `a` bigint(20) NOT NULL /*T![auto_rand] AUTO_RANDOM(5) */,\n"+
 			"  PRIMARY KEY (`a`)\n"+
 			") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin",
 	))

go.mod

@@ -38,7 +38,7 @@ require (
 	github.com/pingcap/goleveldb v0.0.0-20191226122134-f82aafb29989
 	github.com/pingcap/kvproto v0.0.0-20200330093347-98f910b71904
 	github.com/pingcap/log v0.0.0-20200117041106-d28c14d3b1cd
-	github.com/pingcap/parser v0.0.0-20200326020624-68d423641be5
+	github.com/pingcap/parser v0.0.0-20200331080149-8dce7a46a199
 	github.com/pingcap/pd/v4 v4.0.0-beta.1.0.20200305072537-61d9f9cc35d3
 	github.com/pingcap/sysutil v0.0.0-20200309085538-962fd285f3bb
 	github.com/pingcap/tidb-tools v4.0.0-beta.1.0.20200306084441-875bd09aa3d5+incompatible

go.sum

@@ -269,8 +269,8 @@ github.com/pingcap/kvproto v0.0.0-20200330093347-98f910b71904/go.mod h1:IOdRDPLy
 github.com/pingcap/log v0.0.0-20191012051959-b742a5d432e9/go.mod h1:4rbK1p9ILyIfb6hU7OG2CiWSqMXnp3JMbiaVJ6mvoY8=
 github.com/pingcap/log v0.0.0-20200117041106-d28c14d3b1cd h1:CV3VsP3Z02MVtdpTMfEgRJ4T9NGgGTxdHpJerent7rM=
 github.com/pingcap/log v0.0.0-20200117041106-d28c14d3b1cd/go.mod h1:4rbK1p9ILyIfb6hU7OG2CiWSqMXnp3JMbiaVJ6mvoY8=
-github.com/pingcap/parser v0.0.0-20200326020624-68d423641be5 h1:fXVqoeYfV+xI8K2he5NNv00c6YksrjeM6+vkNo1ZK2Q=
-github.com/pingcap/parser v0.0.0-20200326020624-68d423641be5/go.mod h1:9v0Edh8IbgjGYW2ArJr19E+bvL8zKahsFp+ixWeId+4=
+github.com/pingcap/parser v0.0.0-20200331080149-8dce7a46a199 h1:ooT7ZSLDA1VkTXppmDxCEmJO3p/nWWIBQG+3pOguSK0=
+github.com/pingcap/parser v0.0.0-20200331080149-8dce7a46a199/go.mod h1:9v0Edh8IbgjGYW2ArJr19E+bvL8zKahsFp+ixWeId+4=
 github.com/pingcap/pd/v4 v4.0.0-beta.1.0.20200305072537-61d9f9cc35d3 h1:Yrp99FnjHAEuDrSBql2l0IqCtJX7KwJbTsD5hIArkvk=
 github.com/pingcap/pd/v4 v4.0.0-beta.1.0.20200305072537-61d9f9cc35d3/go.mod h1:25GfNw6+Jcr9kca5rtmTb4gKCJ4jOpow2zV2S9Dgafs=
 github.com/pingcap/sysutil v0.0.0-20200206130906-2bfa6dc40bcd/go.mod h1:EB/852NMQ+aRKioCpToQ94Wl7fktV+FNnxf3CX/TTXI=

sessionctx/binloginfo/binloginfo.go

@@ -14,7 +14,6 @@
 package binloginfo
 
 import (
-	"fmt"
 	"math"
 	"regexp"
 	"strings"
@@ -23,14 +22,14 @@ import (
 	"time"
 
 	"github.com/pingcap/errors"
-	"github.com/pingcap/parser"
 	"github.com/pingcap/parser/terror"
 	"github.com/pingcap/tidb-tools/tidb-binlog/node"
 	pumpcli "github.com/pingcap/tidb-tools/tidb-binlog/pump_client"
 	"github.com/pingcap/tidb/config"
 	"github.com/pingcap/tidb/kv"
 	"github.com/pingcap/tidb/metrics"
 	"github.com/pingcap/tidb/sessionctx"
+	driver "github.com/pingcap/tidb/types/parser_driver"
 	"github.com/pingcap/tidb/util/logutil"
 	"github.com/pingcap/tipb/go-binlog"
 	"go.uber.org/zap"
@@ -300,16 +299,17 @@ func SetDDLBinlog(client *pumpcli.PumpsClient, txn kv.Transaction, jobID int64,
 }
 
 const specialPrefix = `/*!90000 `
-const specialVersionPrefix = `/*T!%s `
 
 // AddSpecialComment uses to add comment for table option in DDL query.
 // Export for testing.
 func AddSpecialComment(ddlQuery string) string {
-	if strings.Contains(ddlQuery, specialPrefix) || parser.SpecVersionCodePattern.MatchString(ddlQuery) {
+	if strings.Contains(ddlQuery, specialPrefix) || strings.Contains(ddlQuery, driver.SpecialCommentVersionPrefix) {
 		return ddlQuery
 	}
 	ddlQuery = addSpecialCommentByRegexps(ddlQuery, specialPrefix, shardPat, preSplitPat)
-	ddlQuery = addSpecialCommentByRegexps(ddlQuery, fmt.Sprintf(specialVersionPrefix, parser.CommentCodeAutoRandom), autoRandomPat)
+	for featureID, pattern := range driver.FeatureIDPatterns {
+		ddlQuery = addSpecialCommentByRegexps(ddlQuery, driver.BuildSpecialCommentPrefix(featureID), pattern)
+	}
 	return ddlQuery
 }
 

sessionctx/binloginfo/binloginfo_test.go

@@ -549,15 +549,15 @@ func (s *testBinlogSuite) TestAddSpecialComment(c *C) {
 		},
 		{
 			"create table t1 (id int primary key auto_random(2));",
-			"create table t1 (id int primary key /*T!30100 auto_random(2) */ );",
+			"create table t1 (id int primary key /*T![auto_rand] auto_random(2) */ );",
 		},
 		{
 			"create table t1 (id int auto_random ( 4 ) primary key);",
-			"create table t1 (id int /*T!30100 auto_random ( 4 ) */ primary key);",
+			"create table t1 (id int /*T![auto_rand] auto_random ( 4 ) */ primary key);",
 		},
 		{
 			"create table t1 (id int  auto_random  (   4    ) primary key);",
-			"create table t1 (id int  /*T!30100 auto_random  (   4    ) */ primary key);",
+			"create table t1 (id int  /*T![auto_rand] auto_random  (   4    ) */ primary key);",
 		},
 	}
 	for _, ca := range testCase {

types/parser_driver/special_cmt_ctrl.go

@@ -0,0 +1,55 @@
+// Copyright 2020 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 driver
+
+import (
+	"fmt"
+	"regexp"
+
+	"github.com/pingcap/parser"
+)
+
+// To add new features that needs to be downgrade-compatible,
+// 1. Define a featureID below and make sure it is unique.
+//    For example, `const FeatureIDMyFea = "my_fea"`.
+// 2. Register the new featureID in init().
+//    Only the registered parser can parse the comment annotated with `my_fea`.
+//    Now, the parser treats `/*T![my_fea] what_ever */` and `what_ever` equivalent.
+//    In other word, the parser in old-version TiDB will ignores these comments.
+// 3. [optional] Add a pattern into FeatureIDPatterns.
+//    This is only required if the new feature is contained in DDL,
+//    and we want to comment out this part of SQL in binlog.
+func init() {
+	parser.SpecialCommentsController.Register(string(FeatureIDAutoRandom))
+}
+
+// SpecialCommentVersionPrefix is the prefix of TiDB executable comments.
+const SpecialCommentVersionPrefix = `/*T!`
+
+// BuildSpecialCommentPrefix returns the prefix of `featureID` special comment.
+func BuildSpecialCommentPrefix(featureID featureID) string {
+	return fmt.Sprintf("%s[%s]", SpecialCommentVersionPrefix, featureID)
+}
+
+type featureID string
+
+const (
+	// FeatureIDAutoRandom is the `auto_random` feature.
+	FeatureIDAutoRandom featureID = "auto_rand"
+)
+
+// FeatureIDPatterns is used to record special comments patterns.
+var FeatureIDPatterns = map[featureID]*regexp.Regexp{
+	FeatureIDAutoRandom: regexp.MustCompile(`(?i)AUTO_RANDOM\s*(\(\s*\d+\s*\))?\s*`),
+}