singleflight: fix flaky TestForget

There can be a race condition in current TestForget, that said when
"close(secondCh)" is executed, the second goroutine will be finished
immediately, causing the third "g.Do" is evaluated.

To fix this, we change to use "g.DoChan" for both second and third. In
second, we block to make sure it's still running at the time we call
third. after then we unblock second and verify the result.

Fixes golang/go#42092

Change-Id: I980fdf109a531e2b7a74c8149b4fcaa338775e08
Reviewed-on: https://go-review.googlesource.com/c/sync/+/263877
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
1 file changed
tree: b8d57aa3881802e77fe46c004ca555a73d4437b0
  1. AUTHORS
  2. CONTRIBUTING.md
  3. CONTRIBUTORS
  4. LICENSE
  5. PATENTS
  6. README.md
  7. codereview.cfg
  8. errgroup/
  9. go.mod
  10. semaphore/
  11. singleflight/
  12. syncmap/
README.md

Go Sync

This repository provides Go concurrency primitives in addition to the ones provided by the language and “sync” and “sync/atomic” packages.

Download/Install

The easiest way to install is to run go get -u golang.org/x/sync. You can also manually git clone the repository to $GOPATH/src/golang.org/x/sync.

Report Issues / Send Patches

This repository uses Gerrit for code changes. To learn how to submit changes to this repository, see https://golang.org/doc/contribute.html.

The main issue tracker for the sync repository is located at https://github.com/golang/go/issues. Prefix your issue with “x/sync:” in the subject line, so it is easy to find.