ddl: fix a bug when adding an index to a generated column with an expression error

[zimulala]

…ression error

What problem does this PR solve?

Fix the #9214

What is changed and how it works?

If we encounter a decoding error when adding an index, then we directly return the error of adding this index.

Check List

Tests

• Unit test

Related changes

• Need to cherry-pick to the release branch

[zimulala]

/run-all-tests

[jackysp]

LGTM

[zimulala]

PTAL @winkyao @ciscoxll @crazycs520

[xiekeyi98]

rest,LGTM.

[xiekeyi98]

s/Cant/Cannnot

[zimulala]

MySQL uses it to name the error like 'ErrCantDropFieldOrKey'.

[xiekeyi98]

But in TiDB, I think we use Cannot is better.
F.Y.R:

xiekeyi@ubuntu:~/gopath/src/github.com/pingcap/tidb$ grep -rn "ErrCannot"
匹配到二进制文件 bin/tidb-server
匹配到二进制文件 cmd/explaintest/explain_test
executor/simple_test.go:185:	c.Assert(terror.ErrorEqual(err, executor.ErrCannotUser.GenWithStackByArgs("DROP USER", "")), IsTrue, Commentf("err %v", err))
executor/simple_test.go:194:	c.Assert(terror.ErrorEqual(err, executor.ErrCannotUser.GenWithStackByArgs("DROP USER", "")), IsTrue, Commentf("err %v", err))
executor/simple.go:243:		return ErrCannotUser.GenWithStackByArgs("ALTER USER", strings.Join(failedUsers, ","))
executor/simple.go:302:		return ErrCannotUser.GenWithStackByArgs("DROP USER", strings.Join(failedUsers, ","))
executor/errors.go:43:	ErrCannotUser                  = terror.ClassExecutor.New(mysql.ErrCannotUser, mysql.MySQLErrName[mysql.ErrCannotUser])
executor/errors.go:57:		mysql.ErrCannotUser:                  mysql.ErrCannotUser,
vendor/github.com/pingcap/parser/mysql/errname.go:233:	ErrCannotAddForeign:                         "Cannot add foreign key constraint",
vendor/github.com/pingcap/parser/mysql/errname.go:414:	ErrCannotUser:                               "Operation %s failed for %.256s",
vendor/github.com/pingcap/parser/mysql/errname.go:746:	ErrCannotLoadFromTableV2:                                 "Cannot load from %s.%s. The table is probably corrupted",
vendor/github.com/pingcap/parser/mysql/errcode.go:235:	ErrCannotAddForeign                                             = 1215
vendor/github.com/pingcap/parser/mysql/errcode.go:416:	ErrCannotUser                                                   = 1396
vendor/github.com/pingcap/parser/mysql/errcode.go:748:	ErrCannotLoadFromTableV2                                        = 1728
kv/kv.go:97:	// v must NOT be nil or empty, otherwise it returns ErrCannotSetNilValue.
kv/error.go:55:	// ErrCannotSetNilValue is the error when sets an empty value.
kv/error.go:56:	ErrCannotSetNilValue = terror.ClassKV.New(codeCantSetNilValue, "can not set nil value")
kv/memdb_buffer.go:91:		return errors.Trace(ErrCannotSetNilValue)
infoschema/infoschema.go:39:	// ErrCannotAddForeign returns for foreign key exists.
infoschema/infoschema.go:40:	ErrCannotAddForeign = terror.ClassSchema.New(codeCannotAddForeign, "Cannot add foreign key constraint")
infoschema/infoschema.go:329:		codeCannotAddForeign:    mysql.ErrCannotAddForeign,
util/admin/admin.go:92:			return ErrCannotCancelDDLJob.GenWithStackByArgs(id)
util/admin/admin.go:96:			return ErrCannotCancelDDLJob.GenWithStackByArgs(id)
util/admin/admin.go:102:			return ErrCannotCancelDDLJob.GenWithStackByArgs(id)
util/admin/admin.go:743:	// ErrCannotCancelDDLJob returns when cancel a almost finished ddl job, because cancel in now may cause data inconsistency.
util/admin/admin.go:744:	ErrCannotCancelDDLJob = terror.ClassAdmin.New(codeCannotCancelDDLJob, "This job:%v is almost finished, can't be cancelled now")
ddl/db_test.go:461:			err1 := admin.ErrCannotCancelDDLJob.GenWithStackByArgs(jobID)
ddl/db_test.go:615:			c.Assert(checkErr.Error(), Equals, admin.ErrCannotCancelDDLJob.GenWithStackByArgs(jobID).Error())
ddl/db_test.go:1022:			c.Assert(checkErr.Error(), Equals, admin.ErrCannotCancelDDLJob.GenWithStackByArgs(jobID).Error())
ddl/ddl_worker_test.go:375:		{act: model.ActionDropColumn, jobIDs: []int64{firstID + 13}, cancelRetErrs: []error{admin.ErrCannotCancelDDLJob.GenWithStackByArgs(firstID + 13)}, cancelState: model.StateDeleteOnly, ddlRetErr: err},
ddl/ddl_worker_test.go:376:		{act: model.ActionDropColumn, jobIDs: []int64{firstID + 14}, cancelRetErrs: []error{admin.ErrCannotCancelDDLJob.GenWithStackByArgs(firstID + 14)}, cancelState: model.StateWriteOnly, ddlRetErr: err},
ddl/ddl_worker_test.go:377:		{act: model.ActionDropColumn, jobIDs: []int64{firstID + 15}, cancelRetErrs: []error{admin.ErrCannotCancelDDLJob.GenWithStackByArgs(firstID + 15)}, cancelState: model.StateWriteReorganization, ddlRetErr: err},
匹配到二进制文件 ddl/.ddl_api.go.swp
ddl/ddl_api.go:765:			return infoschema.ErrCannotAddForeign
ddl/ddl_api.go:847:					return nil, infoschema.ErrCannotAddForeign
ddl/ddl_api.go:870:				return nil, infoschema.ErrCannotAddForeign

[xiekeyi98]

Oh,I am sorry for that.
Indeed, cant is more used.

xiekeyi@ubuntu:~/gopath/src/github.com/pingcap/tidb$ grep -rn  "ErrCant" | wc -l
130
xiekeyi@ubuntu:~/gopath/src/github.com/pingcap/tidb$ grep -rn  "ErrCannot" | wc -l
36
xiekeyi@ubuntu:~/gopath/src/github.com/pingcap/tidb$ 
···

[crazycs520]

LGTM

[codecov-io]

Codecov Report

Merging #9216 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #9216      +/-   ##
==========================================
+ Coverage   67.22%   67.23%   +<.01%     
==========================================
  Files         371      371              
  Lines       77271    77271              
==========================================
+ Hits        51948    51952       +4     
+ Misses      20682    20680       -2     
+ Partials     4641     4639       -2

Impacted Files	Coverage Δ
ddl/ddl.go	89.53% <ø> (ø)	⬆️
ddl/index.go	80.45% <100%> (+1.13%)	⬆️
store/tikv/lock_resolver.go	41.7% <0%> (-0.95%)	⬇️
executor/join.go	78.38% <0%> (-0.53%)	⬇️
executor/distsql.go	72.53% <0%> (-0.47%)	⬇️
infoschema/infoschema.go	77.63% <0%> (+1.31%)	⬆️

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[xiekeyi98]

LGTM.