*: enable noloopclosure

[hawkingrei]

Signed-off-by: Weizhen Wang wangweizhen@pingcap.com

What problem does this PR solve?

Issue Number: close #xxx

Problem Summary:

What is changed and how it works?

loopclosure will only complain if the captured loop variable is inside of a function closure that preceded by go and defer keyword and is the last statement in the loop's block ([reference][2]).

This linter complain each time it found any captured loop variable inside a function closure. This linter is helpful if you have utilities that abstracts the go behavior, for example:

func main() {
	for i := 0; i < 10; i++ {
		runInGoroutine(func() { fmt.Println(i) })
	}
}

func runInGoroutine(f func()) {
	go f()
}

will pass the go vet's check while fails the noloopclosure check.

It's generally a good idea (unless every bit of performance matters) to extract the function creation part inside your
loop so that you don't accidentally capture the reference and cause unwanted bugs.
For example, code above can be re-written as:

func main() {
	for i := 0; i < 10; i++ {
		runInGoroutine(newIntPrinter(i))
	}
}

func newIntPrinter(i int) func() {
    func() { fmt.Println(i) }
}

func runInGoroutine(f func()) {
	go f()
}

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• Yisaer
• xhebox

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[ti-chi-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/80e7fff0483cafaa3d6e31fb9fe122a2e13efcb4

[hawkingrei]

/run-mysql-test tidb-test=pr/1927

[hawkingrei]

/run-mysql-test tidb-test=pr/1927

[hawkingrei]

/run-mysql-test tidb-test=pr/1927

[hawkingrei]

/run-mysql-test tidb-test=pr/1927

[hawkingrei]

/run-mysql-test tidb-test=pr/1927

[hawkingrei]

/run-mysql-test tidb-test=pr/1927

[hawkingrei]

/run-mysql-test tidb-test=pr/1927

[hawkingrei]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 0599642

[sre-bot]

TiDB MergeCI notify

🔴 Bad News! [2] CI still failing after this pr merged.
These failed integration tests don't seem to be introduced by the current PR.

CI Name	Result	Duration	Compare with Parent commit
idc-jenkins-ci-tidb/common-test	🔴 failed 2, success 9, total 11	16 min	Existing failure
idc-jenkins-ci-tidb/integration-common-test	🔴 failed 2, success 15, total 17	14 min	Existing failure
idc-jenkins-ci/integration-cdc-test	🟢 all 36 tests passed	27 min	Existing passed
idc-jenkins-ci-tidb/integration-ddl-test	🟢 all 6 tests passed	6 min 13 sec	Existing passed
idc-jenkins-ci-tidb/tics-test	🟢 all 1 tests passed	6 min 3 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-2	🟢 all 28 tests passed	5 min 12 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-1	🟢 all 26 tests passed	4 min 23 sec	Existing passed
idc-jenkins-ci-tidb/mybatis-test	🟢 all 1 tests passed	3 min 14 sec	Existing passed
idc-jenkins-ci-tidb/integration-compatibility-test	🟢 all 1 tests passed	2 min 53 sec	Existing passed
idc-jenkins-ci-tidb/plugin-test	🟢 build success, plugin test success	4min	Existing passed