use goleak to autodetect leaks

[szuecs]

replaces #2051 by using https://github.com/AlexanderYastrebov/noleak

One problem I see is uber-go/goleak#83 , so not sure if we want to merge this or better add only fixes for findings and drop the use of goleak. What do you think?

We agreed on that we use only package based tests and I decided to give https://github.com/AlexanderYastrebov/noleak a try since it's simpler than goleak and Uber engineers seem not to be responsive in this project.

Signed-off-by: Sandor Szücs sandor.szuecs@zalando.de

[MustafaSaber]

👍

[AlexanderYastrebov]

not sure if we want to merge this or better add only fixes for findings and drop the use of goleak

Did it discover any leaks actually?

[szuecs]

Yes it does. I was also not able to fix all cases, for example go-redis heartbeat.
Beware of the linked issue, it will find also goroutines spawned by tests that are not part of the test that has the validation enabled. Who knows how this works with Parallel tests.

[AlexanderYastrebov]

One problem I see is uber-go/goleak#83 , so not sure if we want to merge this or better add only fixes for findings and drop the use of goleak. What do you think?

We should definitely include leak fixes!

There is no easy way to fix uber-go/goleak#83 as defer goleak.VerifyNone(t) implementation looks at the snapshot of all goroutines at the test end so it would see goroutines started by other tests.

There is also an older lib https://github.com/fortytw2/leaktest that looks at the diff between goroutine snapshots before test start and after test ends.

Who knows how this works with Parallel tests.

Both libraries provide per-test checks (defer goleak.VerifyNone(t) and defer leaktest.Check(t)()) that would not work well with parallel tests.

go-leak provides goleak.VerifyTestMain(m) to check leaks after package tests (leaktest does not, see fortytw2/leaktest#4) that should work for parallel tests.

I think we should use goleak.VerifyTestMain(m) per package and not pollute tests with defer goleak.VerifyNone(t).
There is also GODEBUG="tracebackancestors=N" flag that simplifies leak debugging, see https://pkg.go.dev/runtime

PS: I was curious how it works and to understand re-implemented it here https://github.com/AlexanderYastrebov/noleak
It compares snapshots before and after test (like leaktest) and also supports TestMain (like go-leak)

[szuecs]

👍

[AlexanderYastrebov]

👍