Plans for supporting t.Parallel

[tsenart]

Hello!

Thanks for this library, it'll definitely come in handy. Would you be able to document the reasons why t.Parallel isn't supported and what ideas you have for addressing the problem?

Thanks

[fortytw2]

Thanks!

So right now, t.Parallel() isn't supported because goroutines from tests that run in parallel tend to show up in the deferred check - making it look like the current test leaks goroutines when it doesn't.

A potential solution I've had in mind is to have a variant of Check() that operates on a *testing.M, which is what the net/http tests do. I haven't had the chance to test it out yet though.

Another idea uses a sort-of context-aware, gross, package global stack-marker, but I don't think that'll pan out the way I'd like.

[tsenart]

Thanks! :-)

[fortytw2]

Can track support for this in #16

Not entirely sure of this solution yet though

[pwaller]

You guys might be interested in the recently implemented golang/go#22289. ("proposal: runtime: support tracking goroutine ancestor tracebacks").

Unfortunately I don't see a way of turning it on at runtime without spawning another process to set the environment variable to turn it on, hmm.

[bwplotka]

Looking forward for this to be done. Can I help anyhow? Any update? (:

[fortytw2]

I haven't worked on this in a long time @bwplotka, you're more than welcome to pick it up!

What I did two years ago was start allowing this via just add a TestMain( helper called CheckMain, that implicitly supports t.Parallel by just checking the entire program. Never got really far / found the need for it in any of my projects or work though, so I stopped using it.

For the last year now, the codebase I work on at $dayjob uses ginkgo, which has a parallel test runner that segments tests into independent binaries during parallel execution, which makes leaktest work as normal (but we don't have a real use case for it).

A solution based on what @pwaller noted last year would probably be the best way forward, feel free to give it a shot! You can message me on gophers slack (same username) if you want to chat about it

[bwplotka]

Awesome, will let know here if I will find time to work on this (: Thanks for tips! 👍